Relay winding (with the generator running) is under the rectified phase voltage of the generator. It is equal to about half the voltage of the generator. If the voltage between the clamp "30" generator and mass is 13.8-14.5 V, the rectified phase voltage is 6-7 V.
The relay contacts close the power supply circuit of the control lamp 6 (see fig. 153). When the ignition is switched on, when the engine (and hence the generator) does not work yet, current from the battery flows through the contacts and the lamp lights up.
After starting the engine and when the car is moving, the lamp should go out, since under the action of the rectified phase voltage, the relay armature should be attracted to the core and open the relay contacts. If the control lamp does not go out after starting the engine and when the car is moving, then this indicates a malfunction in the generator system. In this case, it generates too low a voltage, and consumers are powered by the battery. Relay test data:
- Opening/closing voltage at (25±5) °С, V — 5.3±0.4/0.2—1.5
- Winding resistance at 20°С, Ohm — 29