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Maytag and GE dynamo

Perhaps it would be a good time to return to engines ;-)

Some months ago "Nick H" wrote :-

Worried about the direction of rotation of the dynamo I mentioned in the Maytag thread, I had a look at it and there appears to be nothing to indicate which way it ought to go. It is a two pole machine with fixed brushes on the neutral axis between the main field poles, on which basis it should be equally happy in either direction. There are however two smaller interpoles in line with the brushes, I believe these assist spark free commutation - does their wiring determine the correct rotation?

"Kim Siddorn" wrote :-

Suck it and see, Nick. Rig it up with your lathe and see what kind of output you get.

"Nick H" wrote :-

I'm over thinking again aren't I :-(

KISS - Keep It Simple, Stupid!

"Brian Bailey" wrote :-

Nick, The interpole magnetomotive force neutralizes that portion of the armature reaction within the zones of commutation and produces the proper flux to generate an EMF in the short-circuited coil that is equal to but opposite to the EMF of self-induction. Thus, little or no sparking occurs at the brushes.

The important thing to remember is that an interpole always has the same magnetic polarity as the adjacent main field pole ahead of it IN THE DIRECTION OF ROTATION. Note: this is for generators only --- DC motors are just the opposite, with the interpole having the magnetic polarity of the main pole BACK of it. So if you can figure out the internal wiring you should be able to figure out the direction of rotation.

............................................................................ ............................................................................ ...

Well, with the engine up and running I though I'd better get around to trying the dynamo. It turned out to be quite resolutely anti-clock with practically no output when driven in the other direction - not what is required for the Maytag at all! Investigating further I found that there were two jumpers in the terminal box and after dibbling about with the AVO for a while I concluded that these connected the rheostat and shunt field to the brush / series field / interpole, circuit. Thus by reversing these connections I should be able to reverse the rotation of the machine. Success, at 1380 rpm on the lathe it lights a 100w 240v light bulb with all the dazzling intensity one would expect from a 125v dynamo running 20% slow! Regulation doesn't seem that good with the voltage rising by about 5v when the load is removed - but I wasn't quite sure what to expect in that respect anyway.

Now how to mount it? The proper Maytag Light wore its dynamo over the engine, supported by plates on the cylinder holding-down bolts, (did anyone save pics of the one on ebay recently, the best I can find at the moment is this

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) but, despite being only

1/4KW, the GE dynamo I have is quite a large and heavy lump and 'showing it' to the engine indicated that the top mounted position would not work. Underneath looked a bit more promising, but would make the dynamo vulnerable to fuel spillage and require a certain amount of gymnastic ability to operate the kick start. Then I noticed that the hole spacing on the dynamo was actually the same as that on the engine and moving it to one side to share holes with the long end of the base, the two suddenly looked like they'd always been together!

Shame I don't rally, it'll make a nice little display ;-)

Reply to
Nick H
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Pictures, pictures!

Regards,

Kim

NH said - snip! - Then I noticed that the hole spacing on the dynamo was actually the same as that on the engine and moving it to one side to share holes with the long end of the base, the two suddenly looked like they'd always been together!

Reply to
Kim Siddorn

"Kim Siddorn" wrote:-

Workshop currently too cramped for photography, may haul it into the daylight at weekend, weather permitting - ie whether I feel like it or not!

Reply to
Nick H

Marginally better pic of Maytag Light plant:-

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Get it while it's hot, don't know how long ebay leave these things up.

Reply to
Nick H

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Also try asking at Smokstak

Reply to
bw

Thanks. That shows the layout perfectly, hope I can get my side-by-side arrangement to look as 'together'.

Reply to
Nick H

A few pictures as requested (end of 'Infernal Combustion' album):-

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Reply to
Nick H

I like the configuration Nick, looks like they belong together.

Regards,

Kim Siddorn.

Reply to
Kim Siddorn

"Kim Siddorn" wrote:-

Cheers.

Hard to believe that great lump of dynamo is only 1/4 Kw isn't it, you can see why copying the original Maytag Light layout was a non-starter.

BTW what year is your '72' and which style of base and kick start does it have?

Reply to
Nick H

Dunno guv - how do I tell?

Regards,

Kim Siddorn.

"Nick H" wrote > Hard to believe that great lump of dynamo is only 1/4 Kw isn't it, you can

Reply to
Kim Siddorn

Should be an engine number stamped on the outside of the flywheel rim. Mine is 107211X which equates to early 1947, also has 3-47 stamped on magneto back plate.

Bases and kick start pedals come in several different flavours depending on application - long base and curly pedal on mine were fitted to engines supplied as replacement on some earlier washing machines originally fitted with single cylinder engine.

Marvins Maytag Shed

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has illustrations of many of the parts and a serial number list.

Reply to
Nick H

"Nick H" wrote (snip):-

Nearly right! Checked at lunch time and backplate is actually stamped 47-0 . I presume this is a date code used by the magneto manufacturer (Eisemann), while the number on the rim was applied by Maytag when they built up the engine. Of course the complete flywheel mag is very easily changed and AFAIK the number does not appear anywhere else on the engine.

Reply to
Nick H

I'll have a look next time I'm in the workshop. Bloody cold out there now, I sprayed up a ST gearbox at lunchtime & whilst it has dried OK, it has gone a rather pleasant satin finish.

Currently rather hors de combat due to stinking cold & runny nose!

Regards,

Kim Siddorn. Mechanical Engineers build weapons, Electronic engineers build radar, Civil Engineers build targets.

Reply to
Kim Siddorn

You clearly haven't reached the same level of anorakism as me, just the sort of detail I HAVE to start investigating as soon as I get an engine ;-)

Reply to
Nick H

It's the pleasure of having Another Place in my life, I can obsess over Saxon matters & play with the engines.

Regards,

Kim Siddorn.

Reply to
Kim Siddorn

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