fordson dynamo

philip haynes · Aug 27, 2014

my fordson major which i have just purchased the charging light will not go out.this tractor is positive earth and i have been told i have to have a b5200 b5239 or ab6239 dynamo.the dynamo that is fitted is a 22259k and the only other numbers and letters on the dynamo are c39p2 L1. could any one tell me if this is the right one. can someone help please.

Mike Farmer · Sep 2, 2014

Hi Have you actually checked that the fault is the dynamo that is not charging. it could be the regulator. Mike

richardinnz · Sep 29, 2014

Easy to identify, B5200 is 11amp (sealed ends, no tacho drive) B5239 is 22amp (open ends, no tach drive) B6239 is 22amp (open ends takes the tach drive)
To check a lucas dynamo remove the leads, join the D and F terminals (Big and small) on the back of the dynamo with a jumper lead. Connect a voltmeter between the jumper lead and chassis ground. Start engine at idle, voltmeter should read a voltage, gently increase engine speed, voltmeter should increase beyond 12volts and up to 20 to 30 volts if Dynamo o.k.
Lucas Dynamo is pretty robust, faults usually occur with the voltage regulator mounted on the engine bulkhead in front of the fuel tank.
Hope this helps

fordson dynamo

philip haynes

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Mike Farmer

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richardinnz

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