How to Test a 6-Volt Generator

by Stephen Benham
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Generators convert rotating mechanical energy into electrical energy. They were fitted to cars until the late sixties, when alternators began replacing them. Generators are powered by external forces, such as a car's engine, which uses a generator belt connected around the crankshaft and the generator pulley to rotate the generator's armature at speed. The rotational speed creates electricity that flows down the cables to your battery and other electrical devices. To test if your 6-volt generator is producing the correct voltage, the rotor inside the generator needs to be turning, and then you simply use a multimeter to measure the output.

Step 1

Access your car's battery. It's the simplest way to test if your 6-volt generator is producing the correct voltage.

Step 2

Turn on your car's engine so the 6-volt generator operates. Increase the engine speed a little above idling speed; 1,500 rpm is fine. It may be easier if you have a helper sit in your car to maintain the engine speed while you perform the test.

Step 3

Turn the dial on your multimeter to measure voltage. If it's a digital meter, input the setting to measure volts. If your meter allows you to set a voltage range, then set it between 0 and 10 volts. This will give you a very accurate reading.

Step 4

Place the metal rods on the ends of the two wires from the meter on the battery terminals. The wires are color-coded: red is positive, black is negative. The battery terminals are labeled "Pos" and "Neg," or they may have "+" and "-" stamped on them.

Step 5

Read the meter display panel to find out if your 6-volt generator is producing the correct voltage. If it reads between 7 and 8 volts, it's working correctly. The reading is higher, as generators produce slightly more electricity than labeled to allow for resistance in the cables. If the reading is between 6 and 7 volts, you should get the generator checked out, because if the voltage falls much more, it won't charge your battery properly. If the reading is less than 6 volts, you need to get it checked out quickly because the generator won't be able to charge your battery.

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