Compressor Start Relay Manufacturer,Supplier and Exporter in India
Product Code : EL-RACLE-12848
Jlab Export is a leading Compressor Start Relay Manufacturer,and suppliers in India
This start relay is the current type, with four terminals. Its coil carries the compressor run-winding current. The high current at switch-on pulls the contacts closed and brings in the start winding. As the motor speeds up, the current falls and the contacts drop open again.
Specifications
| Relay type | Current relay |
| Terminals | Four |
| Pin quantity | 4 |
| Minimum order quantity | 10 units |
| Dispatch time | Usually 4–6 working days |
| Manufacturer | JLab (Jain Laboratory Instruments Pvt Ltd), Ambala, India |
Practicals on the Compressor Starting Circuit
A bench exercise comes first. Students hold the relay upright, as it sits on the compressor, and check with a Digital Multimeter that the start contacts are open. Turned upside down, the armature drops and the meter shows continuity. The coil itself reads close to zero ohms.
Next they wire a starting circuit on a domestic compressor such as the 1/6 hp Compressor, which normally starts through a PTC relay. The circuit takes the current relay, the Compressor Protection Overload and the supply. Once the relay has dropped out, they read the running current on the 400A Clamp Meter Compact and compare the start with the PTC method.
Frequently Asked Questions
Does the mounting position of a current relay matter?
Yes. The armature falls open by its own weight, so the relay must sit upright, the way it is made to be mounted. Fitted at an angle it may hold the start winding in, which overheats the winding and trips the overload.
How is a current relay different from a PTC starter?
A PTC starter is a thermistor that heats up and cuts the start winding after a moment. It must cool down again before the next start. A current relay switches on the motor current itself and is ready to restart at once.
Does the relay have to match the compressor?
Yes. A current relay is wound for a band of motor current. If its coil is too insensitive, the contacts may not close and the compressor will not start. If it is too sensitive, the contacts may not drop out and the start winding stays in.
What are the signs of a failed start relay?
The compressor hums, does not start and trips on the overload after a few seconds, and the overload then clicks every few minutes. Blackened terminals or a burnt smell point to the relay, but check the windings and capacitor too.
How do I find the common, start and run pins?
Measure the resistance between each pair of compressor pins with the power off. The highest reading is between start and run. The lowest is between common and run, and the remaining pair is common and start. The two lower readings add up to the highest. Wire the relay only after the pins are known.
Other Starting Circuit Parts
- Hard Start Kit
- Capacitors Start 80 (start capacitor)
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Last updated: 5 November 2026
