300w Charging Set Problems

[James D Teel II]

I have this 1941 dated Charging Set, 300w, Mk 1 that I restored last year. It starts first time, every time, with the pull rope, but won’t start if I hook it up to a battery. It is also now showing that it’s only putting out around .2 or so volts when I test it with my voltmeter. I’ve only run the unit maybe an hour in total since the restoration. I need a place to start looking so that I can troubleshoot this thing. Thanks.

Edited to add a video link to my original output test.
https://youtu.be/tVPG2T4xxJs

[Jordan Baker]

Your problems will be on the generator or control box side, not the engine side of things. I’d check the little switch inside the control box that changes it from generator to starter. Off the top of my head I can’t think of it’s proper name.

[James D Teel II]

Thanks. That’s a good place to start. Do you have a manual for the generator side of the house?

[James D Teel II]

Are you talking about the automatic cutout? Photo courtesy of Jacques Fortin.

[Jordan Baker]

Yes. I’d check that to start. There isn’t much to go wrong in them

[Mike Kelly]

Hi James

Have you tried connecting a load i.e. a car battery or a older 12V Car headlight ?

The cutout contacts might be sticky or dirty.

You can use your multimeter to check the field coils for continuity.

The rheostat ( control knob ) winding might need cleaning as well.

A aerosol can of electrical cleaner sprayed into the cutout and rheostat is a good start. No need to pull things apart to begin with.

[James D Teel II]

Hi Mike. I did try to start it with a good 12v battery. It will barely turn. You’re the second to suggest that it might be a dirty rheostat. It has to be something simple.

[Mike Kelly]

Originally Posted by James D Teel II

Hi Mike. I did try to start it with a good 12v battery. It will barely turn. You’re the second to suggest that it might be a dirty rheostat. It has to be something simple.

Could also be worn brushes or the commutator needs cleaning - or the brushes not seating correctly.

The OM&M made examples are more common here.

The post-war British made BSA manual is on-line http://www.howardengineerium.co.uk/I...t%20Manual.pdf

[James D Teel II]

All good suggestions, and thanks for that manual. It’s slightly different than the one I have.

[James D Teel II]

Anyone have any idea what the resistance value of this filterette is supposed to be? All I’m getting when I try to use a battery to start the set is a spark at the start switch and the set just tries to turn.

Attached link is of me trying to start it before restoration. It wouldn’t start because the magneto was bad amongst other things. As you can see, it’s turning very well here.
https://youtube.com/shorts/b1L97ZSMhms?feature=share

[David Dunlop]

Hi James.

No Filtrette specifications at all in any of my Chorehorse manuals. In 1940 Canadian money, however, it was worth $28.00.

A probable long shot, but did the maker bother to stamp/print the specs anywhere on the Filtrette itself?


David

[Chris Suslowicz]

Originally Posted by James D Teel II

Anyone have any idea what the resistance value of this filterette is supposed to be? All I’m getting when I try to use a battery to start the set is a spark at the start switch and the set just tries to turn.

Attached link is of me trying to start it before restoration. It wouldn’t start because the magneto was bad amongst other things. As you can see, it’s turning very well here.
https://youtube.com/shorts/b1L97ZSMhms?feature=share

The filter resistance should be very low, as the set can charge at 20 amps.

If the output voltage is really low _and_ it won't run as a motor when the start button is pressed with a charged battery connected I'm thinking the stator may have been demagnetised somehow (connecting it up backwards may cause this if you try to start it).

I don't have any manuals for this (even though I have an unissued one in its crate - someone stole the toolbox before I bought it ) so I can't help much on this one.

If there's a section on "Remagnetising the generator" it's probably worth a look.

Best regards,
Chris.

[James D Teel II]

Hi David. There’s nothing I can find on it anywhere that shows any values. As you can see, it doesn’t have much of a value; at least this one doesn’t.

[James D Teel II]

Hi Chris. I have polarized it and it’s still a no go. I was telling Jordan Baker earlier today. When I try to start it using the battery, I get a spark behind the start button. The motor tries to turn, but that’s it. You can see right behind the start button where the spark takes place. There’s s bit of pitting there. Has it been doing it all along? I’ve no idea. I only noticed it when I took off the side plate.

[Mike Kelly]

The sparking might be caused by oxidized contacts somewhere. I guess you have cleaned up the start button contacts and the cut-out contacts. Check the field coils for the correct resistance, there might be a shorted winding.

These are the correct tools for the Chorehorse.

[James D Teel II]

Checking the coils is my next task. I might have shorted one or more when I put it back together.

That’s a lovely NOS tool box. I have one and tools, but I’ve put it together. I’ve been searching for over a year for a proper wrench clip.

[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...


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[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 Kelly]

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 Kelly]

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.