Install the generator on the stand and make the connections as shown in fig. 7-5. Turn on the electric motor of the stand, set the generator output voltage to 13 V with rheostat 4 and bring the rotor speed to 5000 min-1. Let the generator run in this mode for at least 10 minutes, and then measure the recoil current. For a working generator, it should be at least 55 A.
Pic. 7-5. Connection diagram for testing the generator on the stand:
1 - control lamp 12 V, 3 W; 2 - generator; 3 - voltmeter; 4 - rheostat; 5 - ammeter; 6 - switch; 7 - battery.
If the measured value of the recoil current is less, then this indicates a malfunction in the stator and rotor windings or damage to the valves. In this case, a thorough inspection of the windings and valves is necessary to determine the location of the fault.
The voltage at the generator output is checked at a rotor speed of 5000 min-1. Using rheostat 4, set the output current to 15 A and measure the voltage at the generator output, which should be (14,1 ±0,5) At ambient temperature and generator (25±10) °C.
If the voltage is not within the specified limits, replace the voltage regulator with a new known-good voltage regulator and recheck. If the voltage is normal, then the old voltage regulator is damaged and needs to be replaced. And if the voltage still does not fit within the above limits, then it is necessary to check the windings and generator valves.