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SCR Assembly with touch-safe lexan cover.

SCR Assemblies

We design and build Silicon Control Rectifier Assemblies to fit your needs. These assemblies are designed to help control and regulate the output voltage of each individual phase.

Our Capabilities


Power Rating 500 W up to 1 MW
Low/Med. Voltages 120 VAC up to 5 kVAC
High Voltages up to 250 kVAC
  • Input circuit protection
  • Step-start input to limit inrush
  • Current monitor feedback mechanism
  • NRTL to UL 508A, 508C, NFPA79, CE Mark

Power Rating

We can design our SCR Assemblies with power rating from 500W up to 2 MW. This large range for power rating capabilities allows our customers to have a "one-stop-shop" in meeting all of their transformer needs. This convenience allows for time-reduction and efficiency in coordination.

kVA power rating symbol. kVA is the unit of measure.
Frequency sine wave.


Many of our customers have specific requirements that need to be met. Designing a transformer to run at a specific frequency help our customers design solutions that can work as needed. Most commonly, we design 50 Hz and/or 60 Hz units (we can design a single unit that will be able to run at 50 and 60 Hz)1. Furthermore, we can design units to run from 400 Hz upto 500 kHz. This flexibility is enable our customers to design solutions that will work as intended.


We can design and build our SCR Assemblies to either single or three phase configurations. We have built both large and small single phase units to meet our customer's specifications with configurations including Single Phase Three Wire Grounded Midpoint, Single Phase Two Wire Grounded Neutral, and Single Wire Grounded Return. In addition, we can design to numerous three phase configurations, including, but not limited to:

  • Three Phase Wye Four Wire Grounded Neutral
  • Three Phase Wye Three Wire
  • Three Phase Wye Three Wire Grounded Neutral
  • Three Phase Why Four Wire Non-Grounded Neutral
  • Three Phase Delta Three Wire
  • Three Phase Delta Four Wire Grounded Midpoint
  • Three Phase Open Delta Four Wire Grounded Midpoint
  • Three Phase Open Delta Four Wire Grounded Junction
Single-phase transformer schematic symbol.
Custom dimensional drawing of a three phase transformer.

Custom Dimensions

Sometimes the physical and mechanical aspects of your transformer are just as important as the electrical aspects. If a part cannot fit into your system or configuration, an entire design can be rendered useless. We work with our customers on space contraints (i.e., length, width, and height) to ensure designs work flawlessly.


Example 1


Power Rating 5 kW
Frequency 60 Hz
Phases 1
Primary 208/220/240 Vrms @ 5.2 kVA max.
Secondary 0-10/20/30 Vrms @ 0-130 ADC
  • Designed to operate under extreme thermal conditions
  • Solid state relay for inrush
  • SCR firing board
  • Fully-controlled full wave bridge rectifier
  • NRTL to UL 506 and 508A, Canadian and US compliance
  • For use in an industrial water purification system


Width 10.25"
Length 14.00"
Height 8.25"
Weight 125 lbs
Power supply with fan for cooling support. Custom power supply in a rackmount enclosure.

How to Order

What You'll Need

Our engineers are well-versed and knowledgable and will be able to help guide you through the design and spec'ing process. However, even they will need to know a few parameters before they can design your transformer. Below is a list of the things they will need to know in order to design your SCR Assemblies:

  • Power Rating of the transformer (required)
  • Operating frequency (required)
  • Input and output voltages (required)
  • Output current (required)
  • Whether you will be needed an enclosure (required to help attenuate transverse mode noise)
  • Whether or not circuit protection is required
  • Whether or not a saftey EMO swith is needed
  • What attenuation level are you looking for?
  • Termination requirements (i.e., ring-lug compatibility, etc.)

If you do not know how to necessarily spec out a transformer, or need more information, we have many ways of helping you figure it out. To start, check out our Resources Center. If that doesn't help, contact us at the phone number or email address above. One of our Technical Assistants and Engineers will be more than happy to assist you.

How to Contact Us

Quality Transformer and Electronics
963 Ames Avenue
Milpitas, CA 95035
United States

Phone: +1 (408) 263-8444
Fax: +1 (408) 263-8448


Feel free to contact us via the form below. One of our representatives will contact you right away ready to assist you.