1942 - 1947 Chevrolet Shop Manual



	12-11

	the field lead on the field terminal of the regulator. (b) Remove the regulator cover and depress the voltage regulator armature manually to open the points. If the output now drops off, the voltage regulator unit has been failing to reduce the output as the battery came up to charge and voltage regulator adjustment is indicated. (Instructions for adjusting the regulator are covered under the heading "Voltage Regulator Adjustment.") (c) If separating the voltage regulator contacts does not cause the output to drop off, the field circuit within the regulator is shorted and the regulator should be replaced. 3. WITH A LOW BATTERY AND A LOW OR NO CHARGING RATE check the circuit for loose connections, corroded battery terminals, loose or corroded ground strap, and frayed or damaged wires. The high resistance resulting from these conditions will prevent normal charge from reaching the battery. If the entire charging circuit is in good condition, then either the regulator or generator is at fault. (a) With a jumper wire ground the field terminal of the regulator to the engine block or other good ground. Increase the generator speed to determine which unit needs attention. Use care to avoid excessive speed since under these conditions the generator may produce a dangerously high output. (b) If the output does not increase, the regulator needs attention. Check for dirty or oxidized contact points or a low voltage setting. (c) If the generator output remains at a few amperes with the field terminal grounded, the generator is at fault and should be checked further. (d) If the generator does not show any output at all. either with or without the field terminal grounded, very quickly disconnect the generator lead from the generator (GEN) terminal of the regulator and strike it against a convenient ground with the generator operating at a medium speed. If a spark does not occur, the trouble has now been definitely isolated in the generator and it should be removed and repaired. If a spark does occur, likely the generator can build up but the circuit breaker is not operating to permit the current to flow to the battery due to burnt points, points not	closing, open voltage winding, grounded circuit breaker, or too high voltage setting. NOTE—Do not operate the generator with the generator lead disconnected for any length of time since this is open circuit operation and the units will be damaged* A burned regulator resistance unit, regulator winding, or fused contacts can result only from an open circuit operation or extreme resistance in the charging circuit. With these conditions check wiring before reinstalling regulator. DO NOT RUN OR TEST GENERATOR ON OPEN CIRCUIT. TO DO SO MAY DESTROY REGULATOR OR GENERATOR. CHECKS AND ADJUSTMENTS When checking and adjusting current and voltage regulator units, it is essential that reliable instruments be used. A volt ammeter with 1/4 ohm

		Fig. 21-Volt Ammeter Connections for Checking Circuit Breaker variable resistance in series with the ammeter is required for checking and adjusting voltage regulators. CIRCUIT BREAKER (Cut-Out Relay) Disconnect the battery wire from the battery (BAT) terminal of the regulator. Connect the positive lead of the ammeter to the battery terminal of the regulator and the negative lead to the battery wire. Connect the positive lead of the voltmeter to the generator terminal of the regulator and the negative lead to ground, Fig. 21. Gradually increase the engine speed, noting the voltage at which the circuit breaker points close. This should