The three phase SSR switches all three phases simultaneously from a single control signal, replacing a three-pole contactor in heater bank and industrial heating applications where switching frequency would destroy mechanical contacts.
Simultaneous three-phase switching
Three separate single-phase SSRs can switch a three-phase load, but they will never switch at exactly the same instant, and the resulting phase imbalance stresses the load and can trip protection. An integrated three-phase SSR switches all poles together from one control input, keeping the load balanced.
It also simplifies the panel: one device, one control connection, one heatsink assembly instead of three of everything.
Key features
- Simultaneous three-pole switching from a single control input.
- Zero-crossing operation minimising inrush and electrical noise.
- No contact wear — suited to continuous high-frequency cycling.
- Silent — no contactor chatter in the panel.
- Compact compared with three separate relays and their wiring.
- LED status indication.
Technical specifications
| Parameter | Value |
|---|---|
| Type | Three phase solid state relay |
| Load | Three phase AC — resistive heating loads |
| Switching | Zero-crossing, all three poles simultaneously |
| Control input | DC control signal from controller or PLC |
| Mounting | Panel mount on heatsink |
| Cooling | Heatsink required, sized to total load current |
| Status indication | LED |
Typical applications
- Three phase heater banks in ovens, furnaces and dryers.
- Extrusion and injection moulding zone heating.
- Industrial process heating under PID control.
- Any three-phase resistive load with a high switching duty.
How to order
Tell us the sensing gap, the target material, your supply voltage and the output type your controller needs. If you are replacing an existing sensor, a photograph of the body markings is usually enough for us to identify an equivalent. We will confirm the specification and quote — normally the same day.
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Frequently asked questions
Can I use three single-phase SSRs instead?
Electrically you can, but they will not switch at precisely the same instant, which creates a momentary phase imbalance on every cycle. For a balanced three-phase load, the integrated three-phase unit is the better engineering choice and simpler to wire.
How much heat will it dissipate?
Roughly one watt per amp per phase, so a 30 A three-phase load dissipates around 90 W. Size the heatsink and panel ventilation for that total, and check panel ambient temperature in summer conditions.
Need a quote for the Three Phase Solid State Relay?
Send us your application — target material, sensing distance, supply voltage and housing constraint. We will recommend a part, quote it, and ship from Mumbai.