300w Charging Set Problems

[David Dunlop]

James.

I just discovered an oddity in my Chorehorse manuals.

In one OMC publication the Start Procedure with battery advised turning the Rheostat Output Control full Left and adjusting the choke before pressing the Start Button. The other OMC manual states the Rheostat Output Control must be turned full Right. No date codes I can see on either manual to know which instruction is newer and no ‘Errata’ red flags either. Might not hurt to try the procedure both ways.

Also, I found a reference that the four coils should test close to 6 Ohms average, in series, if that helps in your trouble shooting.


David

[James D Teel II]

That does help. Thanks. I’ll test the coils over the next couple of days and will also try adjusting the rheostat. I’ll report back once all this is done.

[James D Teel II]

Tested this morning at 6 Ohms on the dot. I’m waiting for a new ammeter to arrive on Saturday before I reassemble and try again.

[Chris Suslowicz]

I think at this point we've reached the "take the covers off the generator and have a poke around with a meter" stage.

Is there continuity (from the ammeter - the lead that goes into the generator) to the negative (chassis) connection? That should show the resistance of the generator rotor windings (maybe with the field windings in parallel). If it's very high I'd suspect one of the brushes is not making contact with the commutator, or else there's something (a layer of dirt) in the way.

I'll see about downloading the manual later and see what I can come up with to check.

Best regards,
Chris.

[charlie fitton]

You mentioned the rheostat .....have you tried turning it from one direction to the other while cranking?

Have you tried 24v through it?

Not trying to insult, but I always start with the basics...


f

[James D Teel II]

Chris. The cover is off. What I’ve found is that I have only 1/2 contact on two brushes (I can see light between half of the brush and the commutator), and full contact on the other two. It must just be a coincidence that it measured 6 ohms in total. They’re worn enough that I can’t coax the two into making full contact. Now, I’m searching for either NOS brushes, or a suitable modern substitute that measures out. Yes. I should have replaced them when I originally had it apart. They’re held in place by what appears to be a bent wire affair that looks like a set of staples. It seems that to take them out, I must straighten the wire, pull the brushes, replace them, and then bend the “staples” back into place. I’ve replaced more than a few brushes and this appears to be the most complicated. I’m looking for part number 54-102. Ideally, I’d like to find a set of four and a few spares.

Charlie. I seem to recall I have tried to start the set with the rheostat in the full off position, as is indicated in my manual, and in the full on position, but I’m not 100% certain I’ve tried it in the full on position. Also, why would I apply 24v to a 12v genset? Please advise what you’re thinking. Thanks much.

[charlie fitton]

Firstly, I'm thinking that there may be dead spots in the rheostat, and secondly - 24 v is not going to ham this, if the cranking speed jumps remarkably, it may tell you more about what's going on.


f

[James D Teel II]

Im tracking with what you’re thinking. Thanks for breaking it down.

[James D Teel II]

Originally Posted by David Dunlop

James.

I just discovered an oddity in my Chorehorse manuals.

In one OMC publication the Start Procedure with battery advised turning the Rheostat Output Control full Left and adjusting the choke before pressing the Start Button. The other OMC manual states the Rheostat Output Control must be turned full Right. No date codes I can see on either manual to know which instruction is newer and no ‘Errata’ red flags either. Might not hurt to try the procedure both ways.

Also, I found a reference that the four coils should test close to 6 Ohms average, in series, if that helps in your trouble shooting.


David

This is from a 1961 manual that I found online. It mentions turning the rheostat to high when starting from a battery.

[James D Teel II]

So. I’m at a complete loss. Everything seems to check out okay. All the connections are clean. I’ve removed the brushes and have sanded them to where they make total contact with the commutator. I then reinstalled them. When I took the ammeter out the other day, it actually fell apart, so I ordered a replacement that’s a very good facsimile. I installed that this evening and put everything back together. It won’t start on the battery. The only thing I can think of that to me makes sense is that I’ve put the control box together wrong.

I need an exploded parts diagram or a few, good, detailed photos so I can make sure I have this thing right.

[Mike K]

Originally Posted by James D Teel II

So. I’m at a complete loss. Everything seems to check out okay. All the connections are clean. I’ve removed the brushes and have sanded them to where they make total contact with the commutator. I then reinstalled them. When I took the ammeter out the other day, it actually fell apart, so I ordered a replacement that’s a very good facsimile. I installed that this evening and put everything back together. It won’t start on the battery. The only thing I can think of that to me makes sense is that I’ve put the control box together wrong.

I need an exploded parts diagram or a few, good, detailed photos so I can make sure I have this thing right.

Seems like something is not wired up correctly or a component is U/S. If all else fails I would try to by-pass the ammeter and the cut out . I mean: try to connect your + battery lead directly to the + side of the circuit , you may have to remove the control box cover to try this.

You could have a dud rheostat. Does it check out OK with your multimeter ?

[James D Teel II]

The rheostat is rated at 10 ohms. It tests out at 11 ohms with no breaks anywhere in the circuit.

[James D Teel II]

Okay. It’s repaired. I told you it would be something simple. Take a look at these two photos. In the second photo. See the Bakelite piece going up instead of hanging down in the first photo? That, combined with not putting the rheostat in the full on position with the battery caused it to not start.

Thank you all for your help in working me through this. That Bakelite piece caused the start button to ground out just enough against the case that it couldn’t overcome the resistance, especially if the rheostat was in the wrong position.

[Mike K]

That was a difficult fault to track down.

I had trouble with the shielded ignition lead on my chorehorse. The in-line suppressor resistor in the lead caused a weak spark. That resistor problem took me a long time to to find.