Alternator on MH44

[Charles TX]

Converted MH44 to 3-Wire 10SI 63 amp alternator used generator pulley, which is 4.5 inch diameter. Having problems getting the alternator to excite. My current method to get the the thing to charge is to push the governer linkage past full thottle. I have read that the generator pulley will work and if a 3-wire is used it will excite at low rpm. Any ideas or suggestions. I really don"t want to change the set-up without knowing the best solution. Thanks

 

[Bob]

At startup, before it excites, what are the voltages at the #1 and #2 terminals on the alternator?

 

[Jeff Z.]

You can put in this kit and change it to a single wire which will excite at lower speed.
Single Wire Kit

 

[Bob]

NO WAY will a "single wire alternator" excite at a lower speed than a properly-functioning (and properly connected) "3-wire alternator".

 

[Anonymous-0]

What kind of idiot light did you use? You need a relatively low resistance light to provide enough current to the alternator to get it to start charging. A commonly recommended solution is a 194 side marker lamp. The one I usually use is Radio Shack 12VDC Lamp Assembly 272-332.

If you use an LED or other high resistance lamp as your idiot light, (easy to do given their prevalence at the auto parts store) you will get the behavior you are experiencing. The light will come on with the ignition switch, but won't go out (if at all) until you spin the alternator really fast. Not enough current flows through the high resistance lamp to power up the voltage regulator inside the alternator, you have to wait for the auxiliary diode trio in the alternator to provide power to the regulator.

You can add a 100 ohm resistor in parallel to a high resistance lamp to "fix" the problem with the wrong lamp, or as a test to see if that helps.

 

[Charles TX]

David, You were correct, the idiot light wasn't supplying enought juice to the alternator. Replaced with a diode and it starts charging slightly above idle. Not bad since I have a big pulley on the aternator. Thanks to all for the help.

 

[Charles TX]

Bob, Thanks it was the idiot light.