Inspecting generator field coils

alexiskai

alexiskai

Well-known member
I recently bought a generator from a fellow FB member (thanks Ray!) and I've got it apart to inspect. The field coils are clearly aftermarket. There is some discoloration and I notice they're extremely... sparkly? Is this normal? Is it tiny fragments of the brushes, which I notice are moderately worn?

Contemplating whether I should buy new field coils before reassembly and installation... I have a local alt/gen shop that has Model A experience, so I would be taking it to them.

(I should add, my coupe came with an alternator, so I have no generator for comparison, nor have I ever seen one apart before.)
 

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Why not take it to the experienced generator shop and have the coils tested. If OK use them. If not,then replace them and install new brushes and bearings.
 
Tom Wesenberg has just informed me, based on the rear plate, that this is a '34 generator. Bad news for me since I'm gonna have a hard time finding assembly diagrams and parts.
 

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Should be no harder to find then a Model A, re the diagrams which would be the same. It's the case that is different not the internals.
 
redmodelt said:
It's the case that is different not the internals.
Click to expand...

I don't think this is true. Tom said he didn't have any voltage regulators in stock that would fit this one. The way the third brush ring attaches to the rear plate is clearly different. The brush holders are clearly different from those in the assembly diagrams. I believe the terminal is also different and possibly the location of the spacer at the front bearing.
 
The field windings look good to me. Clean it all up good before re-assembling it.
 
Like others have said, if the field coils do not have any shorts to ground, use them. These generators are not high voltage so chances of arcing is small.
 
sparkley can come from several places it can be solder thrown from the commutator(usually that is a line all around ) it can be grindings from armature rubbing on the field shoes (there will be marks)-wires rubbed, brush holders rubbing wrong places and possibly brushes themselves-originally that style generator would have the field ground wire brought out of the case along with the power wire so it can be used to connect to the regulator part of the oval cutout.
it looks to be cobbled up with regular primary wire, originally it would be a high strand count very flexible wire cloth covered.
many growlers also had a 110 volt 'test light', this was used to test for grounding of windings, if the light lit there was a ground, if there was weakness in the insulation there could be smoke, this gives you a place to look, clean ,shove a piece of insulating paper in
 
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