4 replies [Last post]
Luddite's picture
Joined: 10/09/2015
Posts: 18

I was out for a ride last night, first time I've used the lights for a few weeks. On stopping, the generator lamp stayed on. On getting home, off came the cover and I found the reverse current contacts closed and staying closwd with the key out. All of the wiring appears OK, no shorts that I can find. The switch contacts are opening when the key comes out. Does anyone have any suggestions of what mught be causing my rev. flow coil to remain energised with the key out?

wa1nca's picture
VBMWMO #8374
Ashfield Ma.
Joined: 09/27/2012
Posts: 358
Voltage Regulator

With the engine not running it should be open
Defective regulator ?

Doug Rinckes states

Test 4: Reverse Current
Use the same process as for Test 2: Cut-In Voltage - but the ammeter must be able to read negative
currents. If it cannot, reverse its connections.
Increase the engine speed until the circuit breaker closes, then slowly drop the revs. The current from the
battery to the generator will slowly fall to zero, then when the revs drop still further (you may need to
adjust the idle speed), the current will fall indicating a reverse current flowing from the battery to ground.
When this reaches -2 to -7.5 amps the circuit breaker should open and the ammeter should indicate zero
[=yellow]If the reverse current is too high, the circuit breaker points may stick and burn the generator, or drain the



Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

Danedg's picture
Joined: 12/25/2008
Posts: 42

Remove the VR and clean the top and bottom points.


'54 R51/3, '65 R60/2, '69 R60/US, '95 Mystic, 74 MG Eldorado

Luddite's picture
Joined: 10/09/2015
Posts: 18
Back on track, after laid low by injury

‘’If the reverse current is too high, the circuit breaker points may stick and burn the generator’’ I’d like to check this hasn’t happened to mine. I assume this means overheat the field coils, destroying the insulation. So I need to check the resistance, does anyone know the resistance value of the field coil, and how to check it?

Captonzap's picture
Joined: 08/21/2014
Posts: 55
This might help

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