Starter motor

[oldchuffer]

I found on disassembly that the field coil wires had become detached and i proceeded to solder them to the terminal, BUT then i checked continuity and discovered the nut on the terminal and the motor body had continuity but I thought the casing should be insulated from the terminal, does that sound right?

IF its a case of the insulation breaking down then i assume i need to remove the terminal and fashion a grommet , again does that sound right?

(but ease of photography i desoldered the join.)

Many thanks for any advice.
Steve [ Guests cannot view attachments ]

[allankelly1]

I would have thought that the motor body provides the earth side of the connection as the motor is fed by one cable so needs an earth connection too

But I guess that you need to know what the resistance was for the field coils to ensure the field coil is not in  short circuit?

No doubt there is an expert here


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[taysidedragon]

I'm sure that the terminal is insulated from the body. When I sorted out my connection the other day I could see some insulation below the outside insulating washer.

[oldchuffer]

Thanks, yes i was thinking the same.

[Bryanj]

Nope it goes via brush to commutator

[allankelly1]

Nope it goes via brush to commutator

Every day is a school day


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[oldchuffer]

OK, so from the terminal to the field coil, then to one of the brushes, through the commutator to the other brush and then to the casing, completing the circuit. Yes?

[McCabe-Thiele (Ted)]

Okay the body of the starter motor when bolted to the crankcase is one side of the connection that must mean to avoid a dead short the bolt that connects the starter cable must be insulated from the motor outer casing.

[Bryanj]

Thats correct. If you look at the brushes one tail(correct name for that wire) is crimp connected to a field winding, which mskes it a bugger to change as you have to cut the existing tail leaving a short bit and solder the new one too it. The other brush bolts on

[oldchuffer]

As a footnote i replaced the terminal bolt, fashioned a new insulator and soldered the field wires back on, all good 
Thanks all for all your help on this query.