Testing older style 40 hp generator.

Long time for me too, but try this. A pos jumper wire to the A terminal. Neg wire to a grd on the gen. Then another jumper wire to the F terminal to ground. If this is wrong I'm sure I'll be corrected. No problem.

Careful when you do this.---It is easy to damage the field windings.------------Do not connect anything to the field windings.

Question Racer, if you don't ground the field how does current flow through them ??

Test it the safe way..... Use a volt meter set to DC volts.

Red meter lead to the "A" (armature) terminal of the generator.

Black meter lead to the "F" (field) terminal of the generator.

Also a small jumper from the "F" terminal to a generator ground.

Now, with a pulley bolted to the generator, hold the pulley up against a spinning wire brush of a shop bench grind wheel (the brush, not the grind wheel!... and no, you won't damage the pulley) and be sure to have the pulley turning in the normal direction (clockwise, looking directly down on it).

With that setup, if the generator is any good, it will register the full 12v voltage reading on the meters scale.

I've done this many times, trust me...... it works just fine with no chance of damaging the generator.

Boobie, you were right about hooking up the jumpers the way you said. It turned over just fine, thanks for the help, you certainly win the Boobie Prize for that information!

Ron

Thank you. I hope the prize is Miller Lite LOL.

I would think the gen is already polarized seeing he motorized it with 12 volts pos to the arm terminal.

What could be fatal about it ?? Curious ??

The old starters with the field coils in them ( not magnets ) will spin the same way weither it is neg or pos connected to it. The only way to change rotation is to reposition the armature plate ( brush holder ) and the it will turn opposite.

I reread everything Boobie had to say and see nothing about him saying being okay to run a generator with reverse polarity. He's merely stating the difference between a "starter" that is equipped with wound field coils in them as compared with a starter that is equipped with magnets.

If he was going to make a stupid statement like "It's okay to run a engine's generator with reverse polarity", I'm sure there would be no question about its wording.

kimcrwbr1 said:

You may also need to polarize the generator. Once you get it all wired and the battery connected take a jumper wire and quickly jump between the Batt and Arm on the regulator you should see a little spark. They only put out max 10 amps and start charging around 1200-1500 rpm I take it yours is an electric shift. I put the generator on my 1961 lark III 40hp it keeps the battery charged when motoring between fishing holes and trolling fast for silvers.

Click to expand...

This isn't an electric shift 40, it is a 1965 Big Twin that I am adding the charging system to. Just like the idea of keeping the battery topped off while out cruising around for the weekend.