Omron G3PE-225B DC12-24V — 25 A SSR, 240 VAC, Zero-Cross
SKU: G3PE-225B DC12-24VUSD 19.00
Compact single-phase solid-state relay for heater control, 25 A load current at 40 °C, 100-240 VAC load voltage, 12-24 VDC control input, zero-cross switching, integrated heat sink, DIN rail / screw mount. Built-in varistor for surge absorption.
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Product Overview
The G3PE-225B DC12-24V is the 25 A zero-cross solid-state relay (SSR) in Omron's compact G3PE single-phase family with integrated heat sink. The integrated heat sink eliminates the need to size and mount a separate heatsink — critical for SSRs because the 1.6 W per ampere heat dissipation of the output thyristor (at 25 A × 1.6 V = 40 W heat dissipation) would otherwise require a substantial aluminum heatsink to keep the junction temperature below the 125 °C Tj max. The G3PE-225B's integrated heatsink keeps the SSR compact (100 mm tall × 22.5 mm wide × 100 mm deep) and ready to mount directly on a DIN rail or panel.
Where the G3PE-225B fits in the G3PE single-phase family
The G3PE single-phase family ranges from 15 A to 45 A in 100-240 VAC and 200-480 VAC versions, with zero-cross (B) and non-zero-cross (BL) switching variants. By current rating: G3PE-215B (15 A at 40 °C), G3PE-225B (25 A at 40 °C — this SKU), G3PE-235B (35 A at 25 °C), G3PE-245B (45 A at 25 °C). The 200-480 VAC high-voltage branch uses the same model numbers with a 5 prefix: G3PE-515B (15 A), G3PE-525B (25 A), G3PE-535B (35 A), G3PE-545B (45 A).
Zero-cross switching vs non-zero-cross for heater loads
The G3PE-225B's zero-cross switching turns the output ON only when the AC line voltage is within ±20 V of zero — at 50 Hz this is a 0.8 ms window centered on each zero-crossing (every 10 ms). This eliminates the high di/dt inrush current that occurs when switching at peak voltage (sinusoidal peak is 325 VDC for 230 VAC) into a cold heater element whose resistance is 5-10× lower at room temperature than at operating temperature.
Heat dissipation, derating, and ventilation
The G3PE-225B at 25 A continuous load generates about 1.6 V × 25 A = 40 W of heat (the triac's on-state voltage drop times the load current). The integrated heatsink keeps the SSR's junction temperature below the 125 °C Tj max, but the heatsink's cooling capacity depends on ambient temperature and airflow. At 25 °C ambient the SSR can deliver the full 25 A continuous; at 40 °C ambient (the datasheet's rated condition) it can still deliver 25 A but with reduced margin; at 55 °C ambient the derating curve reduces the maximum current to ~20 A; at 70 °C ambient to ~15 A.
Key Features
- 25 A rated load current at 40 °C ambient
- 100 to 240 VAC rated load voltage
- 12 to 24 VDC control input
- Zero-cross switching
- Integrated heat sink — no separate heatsink required
- Compact slim-profile: 22.5 mm wide, 100 mm tall, 100 mm deep
- DIN rail / screw panel mount
- Built-in varistor for surge absorption
- SKU: G3PE-225B DC12-24V
- Series: G3PE Single-phase Solid State Relays for Heaters
- Voltage: 100 TO 240 VAC
- I/O: 12 I/O
Best-Fit Applications
- Injection-molding machine heater band control — G3PE-225B controlling 6-8 × 230 VAC heating bands via a temperature controller with PID.
- Food-processing oven heater control — G3PE-225B controlling 3 × 5 kW convection heater elements at 230 VAC, PID control via.
- Packaging-machine heat-seal jaw control — G3PE-225B controlling 2 × 1.5 kW heat-seal band heaters at 230 VAC, on/off control via.
- Plastic-extrusion line zone temperature control — multiple G3PE-225B units controlling 200-400 W band heaters at 230 VAC, integrated heatsink allows.
Buying Checklist
- Pick G3PE-225B DC12-24V for 25 A single-phase heater control with integrated heatsink and zero-cross switching
- Pick G3PE-215B DC12-24 for 15 A version
- Pick G3PE-235B DC12-24 for 35 A version
- Pick G3PE-225BL DC12-24 for non-zero-cross variant
- Pick G3PE-525B DC12-24 for 200-480 VAC high-voltage version
- Pick G3PE-325B DC12-24 for 25 A per-phase 3-phase version
Technical Specifications
| Model | G3PE-225B DC12-24 |
|---|---|
| Series | G3PE Single-phase Solid State Relays for Heaters |
| Type | Single-phase zero-cross SSR with integrated heat sink |
| Rated Load Voltage | 100 to 240 VAC |
| Operating Load Voltage Range | 75 to 264 VAC |
| Rated Load Current | 25 A at 40 °C ambient (with derating above 40 °C) |
| Minimum Load Current | 0.5 A |
| Inrush Current Resistance | 250 A peak (1 cycle, 60 Hz) |
| Control Input Voltage | 12 to 24 VDC |
| Control Input Range | 9.6 to 30 VDC |
| Control Input Current | 10 mA max at 24 VDC / 7 mA max at 12 VDC |
| Must-Operate Voltage | 9.6 VDC max |
| Must-Release Voltage | 1.0 VDC max |
| Output ON Voltage Drop | 1.6 V max (at rated current) |
| Leakage Current (OFF state) | 10 mA max (at 200 VAC) |
Resources & Downloads
FAQ for G3PE-225B DC12-24V
What's the difference between G3PE-225B and G3PE-225BL?
Both are 25 A single-phase SSRs with integrated heat sink. The G3PE-225B (this SKU) is zero-cross switching — turns ON only at the next AC line zero-crossing (±20 V of zero) to eliminate inrush current. The G3PE-225BL is non-zero-cross (random-phase) switching — turns ON at any AC phase angle within 1 ms of the control signal.
Why does the G3PE-225B have an integrated heat sink?
An SSR's triac output stage drops about 1.6 V when conducting — at 25 A load current that's 1.6 V × 25 A = 40 W of continuous heat dissipation that must be removed to keep the triac junction below the 125 °C Tj max. Without a heatsink the triac would overheat within seconds and fail.
Can the G3PE-225B switch DC loads?
No — the G3PE-225B is designed for AC load switching only. The output stage uses a triac, which requires an AC line voltage to commutate (turn off) — DC load voltage keeps the triac latched on indefinitely once triggered, even after the control signal is removed.
How do I derate the G3PE-225B at high ambient temperatures?
The G3PE-225B is rated for 25 A continuous load at 40 °C ambient — the datasheet's reference condition. At higher ambient temperatures the maximum continuous load current must be reduced per the derating curve: 25 A at 40 °C, ~23 A at 50 °C, ~20 A at 60 °C, ~17 A at 70 °C, ~13 A at 80 °C.
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