Navigating Heat Treaters’ Most Defining Moments

January 9, 2026 / OP-ED

We like to celebrate the wins for good reason: they inspire us when times get tough. Regardless of where you find yourself in the North American heat treat community, you will face challenges that may redirect your life and prompt you to question your goals or values. Given this universal experience, we asked respected individuals from across the industry to share the hardest decisions of their professional lives. Just as successes inspire resilience, these challenges offer lessons in navigating the toughest moments of your career.

This inspiring piece was first released in Heat Treat Today’s September 2025 Annual People of Heat Treat print edition.

“No Jerks” Rule, with Sarah Jordan

For Sarah Jordan, president and CEO of the cutting-edge casting startup Skuld LLC, hard decisions have paved the path of her career. An earnest visionary — and as down-to-earth as they come — Sarah has made a habit of launching startups for the metal processing industry. Today, she leads a team that has developed a toolless, net-shape casting process and the equipment to perform it, advancing the way parts are formed while minimizing post-processing needs.

It comes to no surprise that her hardest decision came while forging this path. In 2009, Sarah’s first startup, Aesir Metals, faced fall-out from the 2008 economic recession. The impact was most acute when their largest customer informed them that they were unable to pay.

Faced with this reality, Sarah had to make the painful choice to close the company. Just after Christmas that year, every employee was let go. “And that’s awful when everybody’s…you know, they’re counting on you, their families are counting on you.” It was her first time navigating such a challenge, and while it was difficult, it became a formative experience.

Leading her current company, Sarah operates with a “‘no jerks’ rule.” She says culture and people are critical, and the postmortem of Aesir Metals revealed other opportunities for improvement. While mistakes are inevitable — learning requires that — she moves forward, determined not to repeat the same ones.

Upgrade Your Skillset, with Kevin Walters

Kevin Walters
Research & Development Manager
OMG Inc.

Kevin Walters‘s official title is R&D manager at OMG Inc. out in Massachusetts — however, his nickname “Father of Interns” is extremely fitting. With decades of engineering experience, Kevin has dedicated 25 of them (and counting) to mentoring interns, first at Spalding Sports Worldwide and now at OMG. Using his own career for reference, he tells them this story.

Approaching his forties with four boys near or in their teenage years, Kevin began thinking seriously about his career trajectory. He knew that to stay relevant in engineering, he needed to expand his skillset. In this field, the rule is simple: upgrade your abilities or risk becoming obsolete. The question was how.

“I’m a guy who likes to fix stuff — work with my hands,” Kevin told me. The typical career-advancement routes didn’t seem like the right fit: waiting for an opportunity to open up in the company could take too long, a doctorate might pigeonhole him into academia, and an MBA didn’t align with his engineering focus. It took five years of consideration, conversation, and research to find the right path.

That opportunity appeared when he learned about a management degree specifically tailored for engineers. With Spalding’s full “blessing” and tuition reimbursement program, Kevin enrolled at Western New England University, taking two courses per year while balancing his job and his sons’ baseball games. In five years, he had earned his Master’s of Science in Engineering Management.

These kinds of programs have become more widely available, and Kevin encourages his interns to pursue them. “Engineers, if they don’t upgrade their skillset, become obsolete,” he says. “I see too many engineers who graduated with their four-year degree — did great things at the beginning of their career — but because technology is advancing and they’re not learning with it, they are not as useful as they used to be.”

Each summer, Kevin continues mentoring one or two interns, urging them to think strategically about building their résumés and preparing for an industry that never stops moving.

It’s the People, with Dan Bender

Dan Bender
Director of Sales
Control Concepts

As Dan Bender reflects on his 47 years in industry, many as director of sales at Control Concepts, one priority has guided him: bring in business so the people in manufacturing have a job, can feed their families, and keep a roof over their heads.

In the late ’80s and early ’90s, there were a lot of mergers and acquisitions of companies by holding firms. A general attitude that “work is work” within industry started to emerge. He observed that people were being treated as just another factor of direct manufacturing costs.

This inhumane approach was augmented by a larger lack of pride in the business by the leadership. He also perceived that businesses were treated as financial investments; leadership seemed to be just concerned with flipping the company for a profit. Eventually, these factors reached Dan’s workplace.

Desiring more from his employer and wanting to be useful and productive in a place where people mattered, he parted ways. He reflects, “I left a pretty good job and went out to try some other things, realizing I still had a family to support.”

Over the next few years, he explored different roles, leaning on the counsel of friends and mentors from outside the heat treat industry, many of them from his church. Then, in 2008, the recession hit. Dan was working for a European company when it eliminated nearly all North American positions, and for the first time in his career, he was out of a job.

“That was tough,” he commented. “That was a hard, a hard thing…I did some interviews, I had some possibilities, I had some decent things, but I wanted to find somewhere where…people are important.”

His faith was central to that search, and in time, he found the right fit at Control Concepts. While it was not the best offer at the time, it was “what made me feel good, and it [did turn] out to be very financially rewarding for me.”

Choosing to stick with his principles also meant staying in an industry where he had built decades-long relationships. Dan says he looks forward to seeing those connections at tradeshows like Heat Treat 2025 this fall and Furnaces North America next year. “It’s to me, you know…that’s a blessing that I can have conversations with those people and feel a real sense of knowing they are very interested in what you’re doing as well as you being interested in what they’re doing at this stage in their career and your life.” Serving the heat treat industry, and the people in it, is why Dan has no plans to retire anytime soon.

Never Stand Still, with Bill Stuehr

William (Bill) Stuehr
President & CEO
Induction Tooling Inc.

What do you do when an unforeseen market collapse changes the fabric of your business? William (Bill) Stuehr, engineer, founder, and CEO of Induction Tooling Inc., has a clear answer: make a plan and move forward. “I’m a pragmatist,” he says. “I look at things the way they are, then I make decisions and proceed with what has to be done. That’s all.”

In 2005, Bill built a brand-new facility to expand his operations from 14,000 to 30,000 square feet. Business had been picking up for induction heating since the 1980s and ’90s, and manufacturers of driveline components were interested in induction. Induction was becoming more accepted on two fronts: first, as a green energy source; second, as an integrated manufacturing step in cell production, allowing automotive components such as wheel bearings and axle shafts to come out finished at the end of the line. With the expectation to expand to 50 employees by 2015, the city even granted Induction Tooling a tax abatement to encourage expansion and boost the local economy.

The critical moment happened in 2009, beginning on the heels of the 2008 financial crisis. With the housing collapse, people stopped purchasing automobiles, and the automotive industry went reeling. In April and June, General Motors and Chrysler appeared before U.S. Congress after filing for bankruptcy. Bill’s tier 1 automotive manufacturing customers began shutting down operations. “I had never seen it in my career, ever.”

Work was running out. Bill made the hardest decision of his career: “I had to lay off half of my workforce. I went from 28 people to 14 in less than a year.” Some of them had been with him since he started in the late 1970s. “It was out of my control. I tried to keep them on as long as possible without suffering the financial hardship of my own.” Even in hard times, the company covered all employee medical insurance, a practice Bill maintains to this day.

By 2012, the market showed signs of recovery. Bill pivoted the business to focus almost exclusively on CNC automation for rebuilding tooling — a move that met the needs of their tier 1 customers with high production rates and sidestepped the challenges of rehiring or retraining a large workforce.

Commenting on today’s market, Bill revealed it had never truly recovered. “The buyers of the automotive companies had the time to seek outsourcing worldwide.” He continued, explaining that over the course of the four years that followed the crash, there was enough offshoring of driveline components to an enthusiastic, energetic workforce with new facilities and abilities. Reshoring to the U.S. has not gained back the momentum that it had, though perhaps that will change with the priorities of the current U.S. administration.

From those years came a few lasting lessons. First, embrace automation to keep the business profitable, especially when attracting young talent is a struggle. Second, when hard times come, make a plan and commit — but remember that you can’t control time, the weather, or other people. Bill sums it up with gritty simplicity: “You never stand still; you just keep going. ‘What do I have to do and how can I get it done?’ That’s it.”

Bethany Leone
Managing Editor
**Heat Treat Today**
**Contact:** Bethany Leone at bethany@heattreattoday.com

Navigating Heat Treaters’ Most Defining Moments Read More »

Heat Treat Radio #128: Silicon Carbide Without Transformers: How Is That Possible?

December 18, 2025 / CONTROLS TECHNICAL CONTENT, HEAT TREAT RADIO, MANUFACTURING HEAT TREAT TECH

In this episode of Heat Treat Radio, Tony Busch of Control Concepts, Christina Clowes of I Squared R, and Dr. Stephen Feldbauer of Abbott Furnace Company join host Doug Glenn to discuss a new transformer-free approach to electrically heated furnaces. The group walks through how SCR power controllers paired directly with silicon carbide heating elements can reduce system cost, simplify design, and improve control accuracy. They also explore the global adoption of zero-cross technology and its growing relevance in North America.

Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.

Heat Treat Today · Heat Treat Radio 128: Silicon Carbide Without Transformers: How Is That Possible?

The following transcript has been edited for your reading enjoyment.

Introduction (0:45)

Doug Glenn: We’re going to be talking about a relatively new combination of two fairly well-known technologies that will help some people save money. Those two technologies are SCR power controllers and silicon carbide heating elements. It’s actually kind of a little case study. If you’ve got an electrically heated furnace, this would be one you’ll want to stay and hear.

Clockwise from top left: Doug Glenn (host), Christina Clowes of I²R Elements Company, Tony Busch of Control Concepts, and Dr. Stephen Feldbauer of Abbott Furnace Company

Our first guest is Tony Busch from Control Concepts. Tony Busch is the North American sales manager for Control Concepts. Next is Christina Clowes, the vice president over at I²R Elements Company. Our final guest is Dr. Stephen Feldbauer, the director of research and development at Abbott Furnace Company.

A Furnace with a New Configuration (1:45)

Doug Glenn: To get a sense of this furnace that we’re talking about, can you describe the situation and this new configuration of power controls for the heating elements?

Steve Feldbauer: What I can say is that this was a new piece of equipment to replace an old technology for a new facility.

Okay, so they were going to move to a new facility and they said, “Hey, we don’t want this old stuff. Let’s look at just buying a new furnace for this application.”

This is for the casting industry. The molds go into the furnace and traverse through; the furnace preheats them so that operators can then pull them out and fill them with metal. So it’s a continuous furnace for mold preheating application for the casting industry.

It was exciting! We had an electrically heated furnace, and then began talking with Tony and Christina. Control Concepts had this concept, no pun intended: Traditionally, design of an electrically heated furnace above a certain temperature (1850 degrees), we use silicon carbide heating elements and — due to resistance changes over time — we have to put transformers in there that allow us to keep upping the voltage and maintain heating capability. Control Concepts said, “Hey, we can take innovate technology and save some money, make things a little easier, and get rid of the transformers.”

And we really had a great outcome.

Doug Glenn: This is a foundry industry application, the preheating of molds, and this is a continuous furnace. You guys, Abbott, obviously won that bid to supply that furnace. I’m sure it was a competitive situation, so congratulations.

Traditional SCR and Silicon Carbide Heating Element Configuration (4:40)

Doug Glenn: So Tony, one of the great features of this Abbott furnace that helped them win this order was this relatively new configuration of the power supplies. as Steve was saying. Tell us a little bit more about the SCRs and the silicon carbide heating elements.

Tony Busch: I think it’s important to understand where we came from and where we are now with this new technology.

In the past, at least in North America, silicon carbide heating elements produce a high temperature, a high current. To help that happen and so you do not have a big, thick gauge wires, a transformer would be added to the design very close to the furnace. This reduces the conductor size. That transformer often was a multi-tap transformer. From a SCR power controller standpoint, you would be controlling the power on the primary side of the transformer, let’s say 480 volt stepping down into 60-70, whatever volts are required for the application. To use a transformer with a power controller, you need phase angle power control.

This is how it has been done in the past with phase angle firing varying every half cycle into the primary of a transformer.

The New Setup (06:09)

Example of SCR power controller units attached directly to industrial furnace. Source: Control Concepts

Doug Glenn: What is the new configuration?

Tony Busch: With the new scheme, we are removing the transformer. Now you have an SCR power controller firing directly into the silicon carbide heating elements.

To do this, you will have to have slightly bigger power controllers, but you’re completely eliminating the transformer and you’re going directly into it. To take it a step further, we use a special firing mode called Fast Zero Cross. This mode satisfies the heating elements.

We are maintaining a very smooth watt density output to the heating elements. You can control it and the power feedback if you need to, which is essentially your unit of measure to control the power, which can be in KW versus voltage or current.

Doug Glenn: That’s on the power side. Control side of things. That’s basically the new arrangement: removal of the transformer; direct feed into the heating element, with some advantages. Christina, how about the heating element? Can you tell us a little bit about the heating element in this situation?

Christina Clowes: This is not a unique heating element in this particular case, because the same heating element configuration probably would’ve been used even if you were using a multi-tap transformer based system.

The key to the operation here is the very rapid switching of full sine waves through the heating elements, where you’re proportioning the “on-to-off” cycles, electrical cycles, so rapidly that the heating element does not have time to respond to the very high instantaneous loadings during each “on” cycle.

For example, in the U.S., typically you are looking at a power supply that’s at 60 hertz, 60 cycles per second. One electrical cycle is one 60^th per second, or 16.66 milliseconds. In that case, if you were regulating the outputs from the heating elements to 50%, you would have one cycle on, followed by one cycle off, and that being repeated continually.

The heating element during that one cycle, that 16.66 milliseconds, does not have enough time to respond firmly to that very high loading. As a result, the RMS voltage, the natural average voltage over time, governs the load into the heating elements. So, you can design around systems based on 480 volts but regulate the RMS output on the controller to whatever the heating element needs to generate the amount of power that’s needed by the process.

The control is the key to this operation.

Doug Glenn: Is it possible to use a standard or any type of heating element or do you need a special silicon carbide type?

Christina Clowes: It is not a special silicon carbide. We designed this particular application around the needs of the process, the operating temperature, the specific loading required for the process. But it is a different control methodology that’s really the key.

New Technology for North American (10:22)

Doug Glenn: While this technology is somewhat new in North America, it is actually not new on a global context. Can you address this?

Christina Clowes: In Europe, this kind of zero-cross base system has been commonplace for quite some years; also in Asia. The difference in North America is, I think, tradition, more than anything else. People have been used to using phase angle control for silicon carbide heating elements. That’s kind of where this technology grew out from, and people have stuck with that because it works. But this new technology though gives an opportunity to save money and space, while achieving the same result.

Doug Glenn: So for the North American market, this is somewhat new. But it is a proven technology. It’s not a new technology that we are still trying to get our hands around. It’s been done globally, which is an important point.

Cost Savings for the Customer (11:45)

Doug Glenn: With respect to cost savings for the customer, can you describe the capital expenditures, operating costs, and even maintenance costs?

Steve Feldbauer: We know that by eliminating the transformer, there’s the substantial costings. The SCR is doing the change in the voltage and controlling and eliminating that need for the transformer.

By eliminating that piece of equipment, you’re seeing upwards of anywhere between a 50 to 75% cost savings per heating zone. That’s a big number. There’s a wide range in that cost savings depending on the size of the heating zone, the size of the furnace, and the number of heating zones. That is a substantial saving.

In addition, the customer sees savings in shipping costs. In this case, removing the transformer reduced the size of the furnace by 2,100 pounds. That goes directly into your shipping cost.

Customers also see a lot less downtime because every time that you would want to change the tap in a traditional furnace, you have to power the furnace down, which interrupts production. There’s a knowledge base needed to know when and how to change the tap. But with this new technology, the furnace just continually operates.

There is also space savings. That transformer takes up space, which limits where we can put in things. For example, for the last line on a continuous furnace with a belt, the placement of the belt is dictated by where we put the transformers because the transformers typically go up underneath the hot box. Without the transformer, we now have flexibility and design.

So, we save in a number of different areas.

Maintenance of the SCR (14:24)

Doug Glenn: Maintenance wise, are the SCRs easier to maintain?

Steve Feldbauer: There is not much maintenance required for the SCRs. Once you put them in and they are set up, our customers really do not have to touch them unless they have to replace them. As far as tuning them and similar maintenance, there’s really not a lot that goes into them. Especially since now, you’re also not changing voltages. There’s not a lot of variability in the system. It’s set up and it just sits there and controls itself.

Advantages for the Customer (17:45)

Doug Glenn: What are the advantages for the customer?

Steve Feldbauer: There are many advantages in terms of cost, maintenance, and the ease in usage. There’s also less training, because you’re not teaching someone when or how to change a tap. This is a marked change in how you look at electrical furnace control in North America. This is something that is widely used throughout the rest of the world, so it’s not a new technology, but it’s new and innovative to North America. If you can optimize and streamline the process, why wouldn’t you?

Upgraded Features: Digitization and Data (18:58)

Doug Glenn: I also understand there are upgraded features because you’ve moved to an SCR and into a digital world with being able to get data back out of the furnace and understand the operation of the system because of the digitalization of it. Do you want to address that?

Tony Busch: By having a digital SCR power controller, you can connect up to your network, whether it’s Ethernet IP or Modbus TCP. You are able to collect all of that data. From that data, you are able to do things such as monitor the KW per hour. If you’re starting your process, and you want to know how much power was consumed during that particular time period, you can reset your KW per hour. Then you can find out how much you consumed when you are done and evaluate your efficiencies. All of that is recorded within the power controller. It’s essentially an industrial grade power meter built in.

Also, now that you are directly coupled with the silicon carbide heating elements, you have a very accurate load resistance monitoring capability. You are able to analyze the resistance and determine the health of your silicon carbide heating elements.

You can also plot a resistance curve. So you would know that if tolerance drifts 10, 20, 30%, you may be looking at a predictive maintenance situation where you look at your heating elements at some point and monitor the load currents. For a three-phase setup, if you notice that one of the phases is unbalanced, you may want to evaluate and determine the cause. You are able to be alerted without manually getting in there with a multimeter and doing your own research.

Christina Clowes: Compared to phase angle firing, which has been historically the most commonly used in North America, switching to a zero-cross system, a full sine wave based system, the SCRs turn on and off at zero volts potential.

To learn more about how SCR power controllers support tighter control when directly coupled with heating elements, you can click the image above to read this in-depth technical article co-written by Tony Busch.

As a result, that doesn’t produce any transient spikes that create a harmonic overlay, so there’s no electrical noise being generated. Utility companies do penalize their customers for generating electrical noise on their supplies.

In addition, because you have false sine waves, you have unity power factor, essentially. There’s no poor apparent power factor, which you have with a phase angle firing because you’re chopping the sine wave and conducting only part of the sine wave.

When you have purely resistive load, in the case of a Star Bar element, there’s no reactance, inductance, or capacitance. But because of the way that a phase angle SCR fires, it appears that there’s a power factor and people pay for energy that they are not consuming. This is more efficient way of driving an element system with a better handle over the energy that you’re consuming.

Doug Glenn: Is it more difficult to engineer these systems?

Christina Clowes: The exciting or interesting part is introducing new technology to people that actually helps them and provides real benefits. The total cost of the system is simplified and reduced, which makes it far more attractive for Star Bar-based systems to be sold into applications.

Doug Glenn: Right, right. Okay. Tony, how about you? What was interesting and challenging?

Tony Busch: Sure, yes. Christina touched on it a little bit. It would be that power factor in harmonics — being able to show the ability and not be penalized from your utilities for power factor and potential harmonics. Those questions come up, you know, pretty much anytime you’re using an electric furnace and SCR power controllers, but it’s much more easy to demonstrate to customers that you’re not going to see any of those issues. And I’ve seen our electric bill. When you’re running phase angle, you get these big old penalties that come up on there. It’s nice to be to pass that savings onto the customers with this new application.

Doug Glenn: Yeah. Yeah, that’s interesting. And Steve, I saved you for last because you were the ones that really had to interface with the customer. What was interesting or challenging for you guys?

Steve Feldbauer: I’ll tell you what, it was exciting for us to be able to provide new technology — new to North America — that number one makes it simpler for the customer to use.

You know, one of the challenges is always trying to teach people, “when do I need to change a tap or is there really some other problem?” Well, this eliminates that. Now we’re helping them to be able to operate the furnace more efficiently. And, you know, they don’t require all of the training.

We’re also able to pass on some cost savings because we aren’t buying that transformer. We’re able to have some leeway internally for design and construction. So all the way around, it’s a win-win, right? For the customer, for us, and for the industry, in general. Because now we’re able to move the heating technology forward.

Sustainability Benefits of the SCR Power Controller (26:31)

Doug Glenn: Yeah. I probably should have asked this question before, but there’s always a lot of talk about sustainability and greenness. Are there advantages here on this system?

Steve Feldbauer: Tony, you want to talk about it? I’m sure you can address the harmonics and different things that actually help out.

Tony Busch: Most definitely. From a power controller standpoint, the efficiency is right around 99.9%; you’re not really getting any losses through the power controller. And now you’re talking about being full wave firing, so you’re not trimming back that sine wave, you’re eliminating all those other harmonics. You should see a benefit from all of your equipment, if they ever experience that as well as, and your utility bill, not seeing that power factor.

Doug Glenn: Yeah. So basically I guess that’s it. The simple answer is if you’re reducing your energy bill, then obviously we’re using less energy and that’s probably less of a carbon footprint depending on where your electricity’s coming from. Well guys, thanks very much. This is a very interesting, great partnership between the three companies, obviously for the benefit of customers. Appreciate you working for the benefit of a customer and for spending a little bit of time with us here today.

About the Guests

Tony Busch
North American Sales Manager
Control Concept

Tony Busch is Control Concept’s North American Sales Manager. Currently in his 15th year with Control Concepts, he has experience in assembly, testing, troubleshooting, field service and an expert understanding of application engineering of SCR power controllers. Tony has a bachelor’s degree in electrical construction from Dunwoody College of Technology which he now applies the electrical concepts to power controllers and their related applications.

For more information: Contact Tony at tony.busch@ccipower.com.

Christina Clowes
Corporate Vice President and Director
I Squared R Elements Co., Inc.

Christina Clowes is the Corporate Vice President and a Director of I Squared R Elements Co., Inc., located in Akron, NY. She has been at I Squared R for the past 9 years and a little over 40 years in the thermal processing industry, focusing on new product and application development.

For more information: Contact Christina at christina.clowes@isquaredrelement.com.

Dr. Stephen Feldbauer
Director of Research and Development
Abbott Furnace Company

Dr. Stephen Feldbauer received his Ph.D. in 1995 from Carnegie Mellon University in Materials Science and Engineering. He joined Abbott Furnace Company in 2002 where he is currently the Director of Research and Development. Dr. Feldbauer is also a Senior Adjunct Faculty member in Engineering at the Pennsylvania State University. He is the author of numerous articles, publications, and has been awarded eight patents in both the USA and Europe. He is an active member of the MPIF, the American Welding Society’s C3 Committee on Brazing, and a co-chair of the Markets committee of NAATBatt International.

For more information: Contact Stephen at sfeldbauer@abbottfurnace.com.

Heat Treat Radio #128: Silicon Carbide Without Transformers: How Is That Possible? Read More »

Microprocessor-Based SCR Power Controllers: Making Your Life Easier

December 14, 2021 / CONTROLS TECHNICAL CONTENT, FEATURED NEWS, MANUFACTURING HEAT TREAT, VACUUM FURNACES TECHNICAL CONTENT

Precise temperature regulation is undoubtedly the top variable in the industrial process that influences the quality of the final product. Using intelligent power control and predictive maintenance, silicon controlled rectifiers (SCRs) play a major role in temperature regulation and in improving the industrial heat treating process. What are SCRs and how do they improve the industrial heat treat process?

In this Technical Tuesday feature, written by Tony Busch, sales application engineer at Control Concepts, Inc. and Meredith Barrett, manager of Marketing and Business Development at Weiss Industrial, discover how SCRs can help you improve temperature regulation.

(This article was originally published in Heat Treat Today’s November 2021 Vacuum Furnace print edition.)

Introduction

Meredith Barrett
Marketing and Business Development Manager,
Weiss Industrial

Tony Busch
Sales Application Engineer
Control Concepts, Inc.

In manufacturing metals and in the heat treat industry, temperature regulation is crucial. SCR power controllers regulate the flow of electricity from the grid to a major heating element in a manufacturing process. Usually, the major heating element is a furnace, kiln, or oven, and the SCR is often connected to the heating element directly or to a transformer connected to the heating element.

The ability to calculate resistance in a furnace can provide information on the overall condition of an element. The SCR collects data and communicates it back to the network. Predictive maintenance is knowing when an element has reached its useful life. This article will define what an SCR power controller is, how it functions, and the different firing modes.

Digital Thyristor/SCR Power Controller Overview

“Thyristor” is a Greek-derived word for “door.” The term is a hybrid of the word thyratron and transistor. As defined by ElectricalTechnology.org, a thyratron is a gas-filled tube that works as an SCR. SCR and thyristor are interchangeable terms in describing a device with four semiconductor layers or three PN junctions with a control mechanism. These small machines are known as latching devices. In the context of electrical engineering, a latch is a type of switch where once it’s on, it will remain on after removing the control signal.

The actual power control module is an advanced electronic device with LED indicators and I/O terminals. The main internal components of an SCR power controller include:

• Semiconductor power devices (SCRs and Diodes)
• Microprocessor-based control circuits normally referred to as the firing circuit
• Heat sink (a means to dissipate the heat generated from semiconductor devices)
• Protective circuits (fuses and transient suppressors)

The diagram below is a very basic model showing one leg of an SCR controller. However, in all electrical designs of power controllers, such as the popular Control Concepts MicroFUSION series featured in this article, each controlled leg requires SCRs back-to-back within the power control module because of alternating current.

Figure 2. Basic model of one leg of SCR controller

How are Digital SCR Power Controllers Superior to Their Analog Predecessors?

“Digital” SCR power controllers are basically a concise way of referring to a power controller unit that utilizes a SCR switch (as opposed to a different switching method such as an insulated-gate bipolar transistor (IGBT)) and has all the above components. Additionally, these units contain microprocessors that make them more of a smart device. They are scalable, and easily paired with other digital units, whereas pairing analog power controllers results in potential emitter gain and bias.

Digital SCR power controllers can provide flexibility unmatched by analog units. This flexibility includes various communication options and the ability to switch through fi ring modes with ease, all without requiring the unit to be changed or rewired. The adaptable nature of digital SCR power controllers allows them to be incorporated into an industrial heat treat process much more effortlessly.

Older analog units are not highly configurable like their digital replacements. Newer SCRs not only have configurable faults and alarms, but also savable configuration files which can easily be loaded onto another unit.

Digital SCR power controllers can obtain accuracy and repeatability previously impossible with analog controllers. Digital units have power regulation capabilities that adjust for both variations from the mains voltage and resistance from the heating element. This form of power regulation is not only the most precise way to regulate temperature, but it also allows for process repeatability.

Synchronization of two units connected to the same power source, firing in zero-cross mode, is not ideal. This means that modules should not sync up so that they are on and off in unison. If this should happen, the process would require a large amount of current to be drawn from the source while the controllers are all on, and none when they are off.

The company’s SYNC-GUARD™ feature, not previously available on older SCR controller modules, reduces the peak current draw required from the source over time by causing each controller to attempt to find a time to turn on when fewer, or no other, controllers are firing. However, it has its limitations. The more controllers that are added to application, the probability of them syncing increases. Once ten or more controllers are utilized in an application, it becomes impossible to not have some sync up despite this feature.

Another key difference is that digital SCR power controllers are always calibrated and will never change. This allows the convenience of being able to “set it and forget it.” Newer models have an option of a digital display which was previously unavailable with analog controllers.

How the Latest SCR Power Controllers Improve Industrial Furnace Operations

SCRs can calculate electrical resistance in a furnace and provide precise power control. Intelligent power control has embedded algorithms which teach functions to calculate data and predict what is likely to happen next in the life of a heating element. This capability can determine partial load loss, resistance change, and complete load loss.

Partial load fault detection is a “watchdog” feature that monitors the system for change in resistance. This is useful for detecting an element failure for loads with multiple parallel elements. The feature monitors a user-set tolerance value that determines the drift from the target resistance in the system.

Therefore, an operator can enter the resistance manually or use the innovative “teach function” with a digital SCR controller. This is a form of artificial intelligence that will allow the SCR to learn the heating element through algorithms. The teach function auto-ramps and intelligently saves different resistance values at various setpoints in a process, eliminating guess work.

SCR power controller units attached to
industrial furnace

Heater bakeout is an aspect of industrial furnace operations where digital SCRs offer a great amount of control. Industrial furnaces, kilns, and ovens are often lined with some sort of refractory or ceramic material that allows them to withstand extremely high temperatures. Typically, this material can get stressed and crack if heated too quickly, particularly in some submersion heaters where moisture can be present.

Modern SCR power controllers have an actual heater bakeout mode that will increase the temperature to the heating element gradually, allowing the furnace to slowly equalize in temperature. If any moisture is present in the heating element, it is baked away, and either way, slowly ramping up the temperature prevents damage to the refractory. This can prevent both costly furnace repairs and downtime.

Another major advantage of digital SCR controllers is tap change indication that informs the operator when to change voltage taps. Some loads, even if they remain the same, still can influence and change the element resistance over a period of time. Because this affects the power factor, a transformer with multiple voltage taps can be used.

Additionally, digital SCR controllers can also be utilized to achieve a constant output power. The tap change indication feature signals the operator when to adjust the voltage taps to a higher or lower setting on a digital display or digitally via the alarm monitor panel.

Predictive vs. Preventative Maintenance

Predictive maintenance has become a popular buzz word related to “Industry 4.0” as we now enter what is known as the fourth industrial revolution, or digitization of a manufacturing process utilizing an interconnected network of smart devices. The goal of both predictive maintenance and preventative maintenance is to increase the reliability of assets, such as an industrial furnace, oven, or kiln used in the heat treat manufacturing process. This not only avoids costly downtime but increases the life of an asset resulting in substantial savings in maintenance costs.

The main difference between the two is preventative maintenance is simply regularly scheduled upkeep, such as a temperature uniformity survey (TUS) on an industrial furnace. Think, for example, of how you have the oil changed every 3,000 miles in your vehicle because it is common practice for extending the life of your engine: that’s preventative maintenance.

Predictive maintenance is more condition monitoring or intelligence gathering on the health of an asset. It is based on present time and continuous data monitoring from smart devices on an industrial network. Predictive maintenance is knowing when an element needs to be fixed or has reached its useful life and needs to be replaced. Knowing the life of the element allows for a structured shut down preventing expensive unscheduled downtime.

How Do SCRs Achieve Intelligent Power Control?

In the instance of intelligent power control, the SCR acts similarly to a dimmer switch on a lighting fixture. It regulates the amount of electricity going into the furnace, just like the dimmer controls the amount of brightness going into the light bulb. The purpose of regulating the electricity to the heating element is to maintain the desired temperature and prevent damage to the asset from power surges or voltage inrush.

“Resistance” is an electrical engineering term that relates to the amount of current that can flow through a heating element of a furnace, machine, or other electronic device that heats up. Technically, this can be something as simple as your household toaster. When the heating element is cold, the resistance to electricity is lower, allowing more current to pass through. When it is hot, its resistance is higher, blocking the incoming current.

Figure 3. AC supply (left) and load voltage (right)

Both variations in the electricity coming from the grid (the mains voltage) and furnace resistance can cause temperature fluctuations. SCR power controllers accommodate for both variations from the mains voltage and furnace resistance by regulating output current utilizing different firing modes.

Firing Modes of SCRs: Phase-Angle & Zero-Cross Explained

What technically is a “firing mode” when it comes to SCRs? As noted in the SCR diagram, the topology of an SCR includes a control circuit also known as a “firing circuit.” The SCR has feedback and logic to determine how it is going to fire the electric sine wave. Thyristors, as SCRs are more commonly known outside of the U.S., have two basic control modes: phase-angle and zero-cross.

Phase-Angle

When a SCR power controller adjusts the voltage using the firing angle, it is known as phase-angle mode. This is analogous to a dimmer switch on a light fixture. The SCR is acting as a dimmer switch on an industrial furnace. Using phase-angle control, each SCR in a back-to-back pair is turned on for a variable portion of the half-cycle that it conducts. This trims every single half sine wave, giving a very smooth output, hence getting the correct kilowatts to the needed load.

In a heat treat application where the SCR is firing directly into the transformer, phase-angle mode will need to be employed. This protects the transformer from saturation. (See Figure 3.)

Zero-Cross

In zero-cross firing mode, the power controller adjusts the duty cycle to regulate the voltage. Each SCR is turned on or off only when the instantaneous sinusoidal waveform is zero. In zero-cross operation, power is applied for several continuous half-cycles, and then removed for a few half cycles, to achieve the desired load power.

In other words, zero-cross is best described as a blinking on and off. You’re firing a certain amount of full wave cycles, then it is going to turn off for a period of time, and then return to the on mode. An average is taken of the cycles that fire versus do not fire, which gives you control.

The on and off nature of zero-cross is beneficial for power factor, and the overall cost is lower than running SCRs in phase-angle applications. Simply stated, running SCR power controllers in zero-cross mode versus phase-angle mode consumes less energy and saves money on the electric bill. Zero-cross also produces little to no harmonics. As illustrated below in Figure 4, you can run SCRs in two-phase versus three-phase mode using zero-cross. If the resistance is varying less than 10%, zero-cross can be applied to the heat treat process.

SCR Power Controller Configurations

Single-Phase

In a single-phase configuration, SCRs are running back-to-back to the load, which is looping back up to L1 and L2. This is the most basic SCR set up.

Three-Phase/3-Leg (6SCR)

Three-phase is wired in a delta or wye and involves three SCR modules connected in a circuit. This is great for phase-angle control where the SCR is firing into transformers. The topology is beneficial for direct firing as well. Three-phase is effective in high inrush current loads that require a current limit, and it also enables the system to phase without blinking on and off.

Three-Phase/2-Leg (4SCR) Zero-Cross Only

This configuration involves two SCR modules controlling two of the legs, and the third leg is connected to the delta or wye but going directly back to supply voltage. This can be more cost effective for an application since it is run in zero-cross mode.

Figure 6. Three-phase/2-leg (4SCR), zero cross mode

Inside Delta

Inside delta configuration is double the wiring. However, it reduces the size of the SCRs needed. Where the SCRs are placed in the circuit in the inside delta configuration will draw less current at the point. This is a more uncommon configuration, and it is found infrequently in the field.

What SCR Is Right For Your Application?

Weiss Industrial, a manufacturer’s representative company, chose to partner with one of the top OEMs to help provide their customers with uninterrupted and efficient plant operations. They teamed up with Control Concepts Inc. (CCI) on their MicroFUSION Power Controllers because they found their product to be the most reliable and their customer service superior. The company’s power controllers are manufactured in the USA in their 54,000 square foot, company-owned facility in Chanhassen, MN.

Tony Busch, sales application engineer, notes that one of the bigger factors to consider in selecting the right SCR power controller is the load type. Some loads require zero-cross fi ring modes, others phase angle only, and in certain cases it does not matter. It can be either zero-cross or phase angle.

The main rule of thumb is to never use zero-cross on fast responding loads, such as infrared lamps and low mass heaters. In this instance, zero-cross will cause too much of an inrush current and can burst lamps and/or fuses down the line. On the other hand, loads in which the resistance changes are less than 10%, such as nickel and iron chromium, zero-cross must be used. Operators also prefer zero-cross in instances where low harmonics are required, as it produces less harmonics than phase-angle firing mode.

Conclusion

In conclusion, SCRs help achieve an integral part of an industrial network that improves the modern heat treat manufacturing process by providing precise and intelligent power control. They also achieve predictive maintenance previously impossible with their analog predecessors. Their advantages are numerous in improving industrial furnace operations and the heat treat manufacturing process.

Other major advantages of SCRs are their high reliability. Since they are solid-state devices, there is no inherent wear-out mode that can be associated with other industrial mechanical machinery that has gears or moving parts. This means little to no maintenance of the SCR power controller.

They have infinite resolution, which means if there is an incoming supply voltage of 480 volts, sequentially, 480 volts will be returned out of the SCR when it is turned on fully. There is no trim back or load loss involved. You can go from zero to 100% if you want to control your voltage, power, or current.

SCRs also have an extremely fast response time, which allows the operator to turn the device on and off very quickly. In North America, voltage is mostly running on 60hz at 120 half cycles per second. SCRs allow you to target a particular half cycle and turn it on and off very quickly. This is a great feature for loads that have high inrush current, acting as a soft starter, to keep from saturating the heating element.

Want to learn more?

Weiss Industrial has partnered with Control Concepts Inc. to produce a PDF document entitled A Guide to Intelligent Power Control & Temperature Regulation Utilizing SCR Technology, which you can obtain by contacting Meredith Barrett, Marketing and Business Development manager at Weiss Industrial: meredith.barrett@weissindustrial.com.

About the Authors:

Tony Busch, a graduate of Dunwoody College of Technology with a degree in Electrical Construction, began his career at Control Concepts, Inc.’s headquarters in Chanhassen, MN as a test technician, quickly transitioning to field service and repairs. In 2014, he began his current position as a sales application engineer and became Bussmann SCCR training certified. Contact Tony at tony.busch@ccipower.com

Meredith Barrett has a Communications degree from Penn State University and over twenty years of experience in sales, corporate communications, marketing, and business development. While her journey into the industrial and manufacturing sector began in 2014 with Siemens Industry, Meredith joined Weiss Industrial in January of 2020 as the Marketing and Business Development manager to assist in building a new marketing department and lead generation program, while also supporting business development. Contact Meredith at meredith.barrett@weissindustrial.com.

Microprocessor-Based SCR Power Controllers: Making Your Life Easier Read More »

The Clean and Pure: 8 Heat Treat Tips

August 27, 2021 / FEATURED NEWS, INSTRUMENTATION TECHNICAL CONTENT, MANUFACTURING HEAT TREAT, QUENCHING TECHNICAL CONTENT

Want a free tip? Check out this read of some of the top 101 Heat Treat Tips that heat treating professionals submitted over the last three years. These handy technical words of wisdom will keep your furnaces in optimum operation and keep you in compliance. If you want more, search for “101 heat treat tips” on the website! This selection features 8 tips to make sure your operations are clean and pure.

Also, in this year’s show issue, Heat Treat Today will be sharing Heat Treat Resources you can use when you’re at the plant or on the road. Look for the digital edition of the magazine on September 13, 2021 to check it out yourself!

Oil and Water Don’t Mix

Keep water out of your oil quench. A few pounds of water at the bottom of an IQ quench tank can cause a major fire. Be hyper-vigilant that no one attempts to recycle fluids that collect on the charge car.

(Combustion Innovations)

Dirt In, Dirt Out!

Parts going into the furnace should be as clean as possible. Avoid placing parts in the furnace that contain foreign object debris (FOD). FOD on work surfaces going into the furnace will contaminate the furnace and the parts themselves. Dirty work in, dirty work out. FOD comes in many forms. Most common: oil, grease, sand in castings or grit blasting operations, and metal chips that generally originate from the manufacturing process before the parts are heat treated. It could also be FOD from the shipping process such as wood or plastic containers used to ship the parts.

(Solar Manufacturing)

Remove Particulates

Adding a strong magnetic filter in line after the main filtration system is an effective way to remove fine, metallic particulates in an aqueous quench system.

(Contour Hardening, Inc.)

Seal Away Dirt or Dusty Environments

Use a sealed enclosure or alternative cooled power controllers for dirty and dusty environments. For heavy dirt or dusty environments, a sealed cabinet with air conditioning or filters is recommended. Alternatively, select a SCR manufacturer that offers external mount or liquid cooled heatsinks to allow you to maintain a sealed environment in order to obtain maximum product life.

(Control Concepts)

Copper as a Leak Check

If maintaining dew point is a problem, and it’s suspected that either an air or water leak is causing the problem, run a piece of copper through the furnace. Air will discolor the copper; water will not.

(Super Systems, Inc.)

Oxygen Contamination Sources

A common source of oxygen contamination to vacuum furnace systems is in the inert gas delivery system. After installation of the delivery lines, as a minimum, the lines should be pressurized and then soap-bubble tested for leaks. But even better for critical applications is to attach a vacuum pump and helium leak detector to these lines with all valves securely closed, pull a good vacuum, and helium leak check the delivery line system. Helium is a much smaller molecule than oxygen and a helium-tight line is an air-tight line. Also, NEVER use quick disconnect fittings on your inert gas delivery system to pull off inert gas for other applications unless you first install tight shut-off valves before the quick disconnect. When the quick disconnect is not in use, these valves should be kept closed at all times. (Though the line is under pressure, when you open a back-fill valve to a large chamber, the line can briefly go negative pressure and pull in air through a one-way sealing quick disconnect valve.)

(Grammer Vacuum Technologies)

Container Clarity Counts!

Assure that container label wording (specifically for identifying chemical contents) matches the corresponding safety data sheets (SDS). Obvious? I have seen situations where the label wording was legible and accurate and there was a matching safety data sheet for the contents, but there was still a problem. The SDS could not be readily located, as it was filed under a chemical synonym, or it was filed under a chemical name, whereas the container displayed a brand name. A few companies label each container with (for instance) a bold number that is set within a large, colored dot. The number refers to the exact corresponding SDS.

(Rick Kaletsky, Safety Consultant)

Discolored Part—Who’s to Blame?

If your parts are coming out of the quench oil with discoloration and you are unsure if it is from the prewash, furnace, or oil quench, you can rule out the quench if the discoloration cannot be rubbed off. Check this before the part is post-washed and tempered.

Other possible causes:

Can be burnt oils as parts go through the quench door flame screen
Poor prewash
Furnace atmosphere inlet (particularly if it is drip methanol)

(AFC-Holcroft)

Check out these magazines to see where these tips were first featured:

The Clean and Pure: 8 Heat Treat Tips Read More »

control concepts