Induction Heating & Furnace Transformers
Rectifier and multi-tap transformers, water-cooled reactors and chokes for induction power supplies, vacuum and resistance furnaces, and SCR thermal controls.
Heavy, Harmonic-Rich Loads That Need Purpose-Built Magnetics
Induction power supplies and SCR-controlled furnaces combine high current, rectifier harmonics and, often, water cooling. Their magnetics are usually custom: rectifier transformers with phase-shifted secondaries, multi-tap transformers that follow heating elements as they age, and reactors built for DC or medium-frequency current.
We help furnace builders, induction equipment OEMs and plant engineers put the right data in front of the right plant. See the furnace & rectifier multi-tap transformers product page for detail.
Where These Magnetics Are Used
- ■ Induction melting & heating power supplies: Rectifier transformers (6 or 12-pulse) and DC link reactors.
- ■ Medium-frequency inverters: Water-cooled inverter reactors and matching transformers.
- ■ Vacuum & atmosphere furnaces: Multi-tap or low-voltage, high-current transformers fed by SCR power controllers.
- ■ Silicon carbide & MoSi2 elements: Tapped transformers that let voltage rise as element resistance changes.
- ■ Plant supply: Harmonic mitigation for large rectifier loads at the point of common coupling.
Furnace & Induction Magnetics at a Glance
| Component | Typical role | What to specify |
|---|---|---|
| Rectifier transformer | Feeds the induction power supply rectifier | kVA, primary voltage, secondary voltage(s), pulse number, phase shift |
| Multi-tap furnace transformer | Matches voltage to heating element resistance | Element type, cold/hot resistance, voltage range, number of taps |
| Low-voltage, high-current transformer | Direct resistance or element heating | Secondary current, voltage, duty, bus connections, cooling |
| DC link / smoothing reactor | Smooths rectified current | DC current, inductance, ripple, water or air cooling |
| Water-cooled inverter reactor | Medium-frequency tank and series reactors | Frequency, current, inductance, water flow and pressure |
What to send for a fast, accurate quote
- Equipment type and power rating
- Supply voltage and frequency
- Secondary voltage and current, or element data (type, resistance, count, wiring)
- Rectifier or SCR controller type and pulse number
- Cooling: air or water (flow, pressure, inlet temperature)
- Duty cycle and ambient temperature
Replacing or Designing Furnace Magnetics?
Send the nameplate of the existing unit or the element and controller data for a new design.
Build a transformer spec sheet Contact usInduction heating and furnace transformers: common questions
Why do silicon carbide heating elements need a multi-tap transformer?
Silicon carbide elements increase in resistance as they age. To keep delivering the same power, the supply voltage has to rise over the element life. A multi-tap transformer, or one with a wide voltage range, lets maintenance move up a tap instead of replacing elements early.
What is different about MoSi2 element supplies?
Molybdenum disilicide elements have very low resistance when cold and much higher resistance when hot, so cold-start current can be several times the running current. The transformer and SCR controller are normally sized with current limiting in mind, and the element maker’s data sets the voltage and current range.
Why use a 12-pulse rectifier transformer on an induction power supply?
Two secondaries phase-shifted by 30 degrees feed two 6-pulse rectifiers, which cancels the 5th and 7th harmonic currents at the primary. That lowers the harmonic load on the plant supply compared with a single 6-pulse rectifier of the same rating.
Can you match a water-cooled reactor from an old nameplate?
Often, yes. Send photos of the nameplate and the coil, the frequency and current, and the cooling water connections. Missing data such as inductance can sometimes be measured on site or recovered from the equipment documentation.