Yet still another starter ?? Question ??

[BILL WZOREK]

This is a bit a follow up or continuation of Johns ( oldford2 ) 6V / 12V starter Question.

Me and Electricty don't always see eye to eye so please bear with me.

Does a ohm meter measure the restance of a wire?
If so can it be used to test the field wires on a assembles starter by putting one lead wire from the ohm guage to the starter case & the other lead wire from the ohm guage to the copper lug coming out of the starter.
To determan which field is in the starter 6V would be one reading & 12V would be another reading.

Or does it not work this way?

[Dec211975]

Bill,

That is correct there would be a difference in resistance from a 12 volt field winding to a 6 volt field winding. However it may not indicate a short to ground old Growlers had a 120 volt light bulb on them and you would check continuity and you would also check to ground; that would usually find the problem. Other test methods would be to use a High pot tester and or Meg-ohm meter that could apply from 1200 volts to 6000 volts across the windings to check the integrity of the windings (If I remember correctly Under Writers Laboratory recommends 1200 volts for 30 seconds to check for insulation integrity on a low voltage DC motor) too much voltage when testing can compromise the varnise "insulation".

Regards,

Brian

[BILL WZOREK]

Brian:THANKS
BUT
What I am trying to ask is / is a starter sitting on the shelf 6V or 12V or in a car for that fact.
The Question has been asked before / How to tell witch it is & I don't know if this method has be talked about.

[rotorwrench]

High torque motors have larger wire in the windings than say a generator. A 12-volt motor draws less amps at the same torque level as a 6-volt so it wouldn't need as large a diameter cross section of wire in it but it still needs large wire for the torque. The resistance might be a bit higher on a 12-volt but I don't know the difference since a person could only compare an early 6-volt to say a 1956 Ford 12-volt starter. My 49 thu 51 Mercury Overhaul Manual doesn't list the resistance factors for the starter field windings. They only have a check for continuity and short to ground.

[old Tom]

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Ho




R, 01-03-2014 07:25:36
Theoretically your idea would work.
HOWEVER both 6 and 12 volt starter resistance values are so low (a few hundredths of an ohm) only a lab grade instruments can measure the difference. It is way beyond the capabilities of your typical VOM/DVMM.

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Incidentally most 6 volt starters do fine on 12 volts. My first ever 12 volt conversion (a '53 Super M) retained the OEM 6 volt starter. 35+ years later the original starter is still working fine.




Re: 12V vs 6V starter in reply to Henryv11, 01-03-2014 07:25:36
In theory yes you could check resistance to figure out if it is a 6 or 12 volt but the common cheap home meter is not going to do that since you would need a very accurate meter that would read down into the very low ohm scale like maybe 10 ohms max. A 6 volt starter will work for decades on 12 volts but if you have a 12 volt starter and try it on 6 volts it will spin very slowly and not likely to start the engine
[


R

The resistance