Zero-Fired Power Supplies

Zero-Fired Power Supplies

MSI Zero Fire Power SupplyZero-Fired Power Supplies are similar in operation to the phase angle-controlled SCR power supply. Zero fired power supplies use SCRs to vary the power to the load. However, instead of varying the firing angle to reduce the RMS voltage, zero fire supplies use a time basis to vary power. Since the waveform is always fully sinusoidal the resultant power factor is much higher. Due to advances in SCR controller technology, these power supplies may be transformer coupled.


  • Up to 600V input
  • Single zone, two zone (3 to 2 phase output), or multiple zones in one enclosure
  • Output command via analog 4-20mA, 1-5V, or other custom signal to meet your control needs
  • Microprocessor SCR gating for precise power delivery improves process quality
  • Microprocessor operating supervision monitors operating conditions for problems caused by faulty loads and power irregularities
  • Easy fault and alarm diagnosis via Internet browser based configuration. No extra software needed to communicate to the power supply. Just a computer and an Ethernet cable!
  • Load matching transformers conservatively designed for long lifespan, even at full power
  • Up to 50°C ambient temperature
  • NEMA 1 enclosure, ANSI 61 gray powder coat is standard; additional colors optional



  • Air conditioned control cabinet for ambient temperatures exceeding 50°C
  • Current limiting available for loads that have low resistance at start up
  • Output voltage and current feedback
  • Touchscreen mounted to control cabinet for diagnostics and monitoring of operating conditions.
  • UL Recognized insulation system (Primary must be 600V or less). MSI UL Insulation systems are available in 130°, 180° and 220°C ratings
  • Final Test Reports with optional Certificate of Compliance


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