# 1967 Ford 3000 diesel



## mississipiboy (Oct 16, 2016)

How do I tell if my generator is charging?


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## RC Wells (Dec 26, 2008)

Unlike alternators, generators do not charge at idle.

If your battery is good, start the tractor and run at high idle, use a voltmeter to read across the battery terminals. Voltage should be 13.8 to 14.2 volts.

Unfortunately, this only tells you the condition of both the generator and voltage regulator. If the battery is not reading voltage in the charging range the problem could be either the generator or the regulator, or both.

A more complicated test that isolates the generator is as follows: Use a battery hydrometer and make sure that the battery is not less than 1.250 specific gravity. 1. Disconnect the wire from the generator regulator marked batt and connect an ammeter in series with its terminal and the disconnected wire. 2. Then connect a jumper wire between the regulator terminal marked F (Field) and the base plate of the regulator, (this bypasses the voltage regulator so it can not operate to control generator output). 3. Start engine with all the tractor's electrics turned off, slowly increase engine speed until ammeter registers 30 amperes, about 1100 RPMs with generator hot (never exceed 1300 RPMs while "F" terminal is grounded). 4. If 30 amperes can not be reached, the generator does not have proper output.

If this last test shows the generator to be good, but the first test at the battery shows low voltage, the problem is likely the voltage regulator.


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