Testing a Voltage Regulator

[BobT-47P15]

I'm pretty sure this has been discussed previously, but like in school, I didn't have need of the info at that moment, therefore was not paying close attention.

I have a Radio Shack multimeter.....can I use it to test output of the regulator? And if so, which setting do I need (volts or amps), and which places do i need to make contact with the probes? One tab of the regulator to another, or a tab and to a ground or to another item in the system? Thanks for any hints.

Had the generator checked by an auto electric shop not long ago....he declared it OK. Battery seems OK - does not run down. Lights get brighter when engine speeds up from idle.

[bob westphal]

Bob,

Just connect the volt meter, set on 20 volts, across your battery. This will tell you how many volts the system is putting out. Most mutimeters only will read miliamps and won't be able to read amps high enough to check your amperage. It sounds as though your system is working as it should if the battery is staying up. It is normal for the lights to get brighter as revs come up with a generator system. However, if you for some reason suspect that the charging system has a problem it is quite easy to checkout. With the engine at about 1500 rpm with lights and accessories on you should show a charge of at least 7V but not over 8V. To see if the the generator is working, disconnect the field wire(the small one)on the generator and short it out to the frame of the generator. Do this only long enough to check the reading. If you leave the wire shorted for a longer time it will melt the solder in you armature. This should give a very high votage. If it doesn't, the generator is faulty. If it does and you still don't show a proper charge, the regulator either needs replacing or adjustment.

Bob

[greg g]

The manual says to connect the meter from the BAT (or A) terminal to ground. Run the engine till the VR is at operating temp. Connect a variable resistance between the Battery terminals, and with the engine running at RPM aproximating 30 mph road speed (1500/1700 rpm) after the charging has droped from its peak it should provide 7.2 to 7.5 volts