Content last revised on August 10, 2026
SanRex PE55FG40 Power Thyristor/Diode Module
The SanRex PE55FG40 delivers dependable power conversion for industrial phase-control rectifiers and motor switching systems. Featuring a 400V repetitive peak reverse voltage rating and an average on-state current of 55A, this module combines high surge withstand capability with effective thermal dissipation. Designed with an electrically isolated mounting baseplate, it enables simplified mechanical assembly and robust electrical safety. For 240V AC industrial rectifiers requiring robust 1300A surge handling and low thermal resistance, the SanRex PE55FG40 module is the optimal choice.
Key Specs: 400V | 55A IT(AV) | Rth(j-c) 0.50°C/W
- Surge Resilience: High 1300A non-repetitive surge current rating protects against AC line transients.
- Isolated Substrate: 2500V AC isolation simplifies heat sink mounting and thermal design.
What is the surge current capability of PE55FG40? It handles up to 1300A surge current for reliable transient protection.
Key Parameter Overview
Decoding Electrical Specifications for Industrial Rectification
Engineers evaluating the PE55FG40 can review its critical maximum ratings and operational parameters in the standard reference table below. These specifications define the thermal, voltage, and current boundaries required for safe design execution in industrial power equipment.
| Parameter | Symbol | Conditions / Test State | Rating / Value |
|---|---|---|---|
| Repetitive Peak Reverse Voltage | VRRM | Tj = 25°C to 125°C | 400V |
| Average On-state Current | IT(AV) | Single phase half wave, 180° conduction, Tc = 81°C | 55A |
| R.M.S. On-state Current | IT(RMS) | Tc = 81°C | 86A |
| Surge On-state Current | ITSM | 50Hz/60Hz half sine wave, 1 cycle, peak | 1300A |
| Maximum On-state Voltage Drop | VTM | Tj = 25°C, IT = 165A | 1.6V |
| Gate Trigger Current | IGT | VD = 6V, IT = 1A | 50mA (Max) |
| Critical Rate of Rise of Off-state Voltage | dv/dt | Tj = 125°C, VD = 2/3 VDRM | 1000 V/µs (Min) |
| Thermal Resistance (Junction-to-Case) | Rth(j-c) | Per semiconductor junction | 0.50 °C/W |
| Isolation Breakdown Voltage | VISO | A.C. 1 minute, terminals to base | 2500V |
Download the PE55FG40 datasheet for detailed specifications and performance curves.
Application Scenarios & Value
Mitigating Transient Inrush in Motor Drives and AC Switching
Industrial motor drives and controlled rectifiers operating on low-voltage AC lines frequently face heavy electrical stress during startup. When line contactors energize a three-phase motor or capacitive bank, line voltage spikes and instantaneous surge currents threaten power semiconductor integrity. The 400V rated SanRex PE55FG40 handles these stresses through its 1300A surge rating, absorbing short-duration overcurrent events without degradation.
In resistance heating control and commercial light dimming circuits, phase-angle firing demands precise gate control and high static dv/dt immunity. The PE55FG40 provides a guaranteed minimum dv/dt capability of 1000 V/µs. This prevents spurious turn-on caused by steep voltage transients, ensuring stable power delivery across inductive and resistive loads. System designers can select the appropriate power module configuration by consulting comprehensive power semiconductor selection guide frameworks.
For applications operating on higher line voltages, such as 440V or 690V industrial grids, systems require higher voltage ratings. While the PE55FG40 serves 120V/240V line conversion, related solutions like the SKKH106/16E offer 1600V blocking capability and higher continuous current capacity.
Technical Deep Dive
Thermal Resistance and Package Insulation Dynamics
Thermal management dictates the long-term reliability of power thyristor modules. The PE55FG40 achieves a junction-to-case thermal resistance Rth(j-c) of 0.50 °C/W per element. Think of thermal impedance as a narrow highway during rush-hour traffic; lower thermal resistance broadens the highway lanes, allowing heat generated within the silicon junction to rush out rapidly toward the aluminum heatsink. This prevents localized hotspot accumulation during continuous 55A operation.
Effective heat removal relies heavily on substrate construction. Understanding why Rth matters in power modules enables engineers to calculate precise heatsink dimensions and thermal interface material (TIM) requirements. The electrically isolated baseplate functions as an internal electrical barrier while conducting heat. You can visualize this isolated substrate as a ceramic heat exchanger; it conducts thermal energy outward while completely isolating live high-voltage terminals from the grounded chassis.
This isolation rating of 2500V AC eliminates the need for external mica insulation sheets. Engineers can mount multiple modules onto a single shared heatsink without risking phase-to-phase short circuits. Combined with gate trigger currents under 50mA, the PE55FG40 simplifies driver circuitry while maintaining thermal margin under varying industrial duty cycles. Designers optimizing power density can reference voltage, current, and thermal management selection guides to balance performance targets.
Frequently Asked Questions
How does the 0.50 °C/W thermal impedance of the PE55FG40 impact heatsink sizing?
A lower Rth(j-c) reduces the temperature rise at the semiconductor junction for a given power dissipation. With 0.50 °C/W per junction, heat flows efficiently to the module case, allowing engineers to utilize smaller heatsinks or maintain lower operating temperatures under full 55A continuous loads.
What is the benefit of an electrically isolated mounting baseplate rated at 2500V AC?
The isolated baseplate allows direct mechanical clamping onto grounded heat exchangers without additional insulating pads. This reduces assembly complexity, improves heat transfer efficiency, and meets safety isolation requirements for industrial motor control systems.
Why is the 1000 V/µs dv/dt rating critical for phase-controlled heating systems?
In phase-control applications, rapid voltage steps occur when thyristors trigger mid-cycle. A minimum dv/dt rating of 1000 V/µs ensures that the thyristor will not misfire due to displacement currents across internal junctions, avoiding unfiltered turn-on events.
Can the PE55FG40 be integrated directly into a standard variable frequency drive (VFD) input stage?
Yes, the PE55FG40 is engineered for utility line rectification stages. In 120V or 240V input Variable Frequency Drive (VFD) systems, it provides reliable AC-to-DC conversion ahead of the main DC-bus filter capacitors.
Evaluating power module specifications against system line voltages, thermal dissipation limits, and surge environments ensures long-term operational integrity. Incorporating robust thyristor architecture into power conversion stages protects industrial equipment against grid disturbances while maintaining predictable thermal performance.
