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ok just added a dynamo off a ford zephyr to my flathead , its a nos one that works fine as it should but i cannot get it to charge through the regulator box .

i have tried three different regs all known to be working and even tried a dynamo that again is known to be working off an anglia but same problem .

i have tried re polarising and i just cannot get it to charge or put out the charge light ?

tried two different style regs and wired them as diagrams below on seperate wiring same problem .

what am i missing guys ?



 

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First thing is that reg boxes are rated by amperage to match the dynamo so you need the correct one for the job. Next was dynamo known to be working before ? I unknown quantity could be something as simple as worn brushes on the dynamo. Have you run it up with an avo direct to the dynamo to check for any output at all?
 

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Here you go, this is a good guide

http://mgaguru.com/mgtech/books/pdf/Lucas_Generator_and_Control_Box_Tests.pdf

You need to check but I think the Zephyr uses an RB340 ( 25 amp) rather than the smaller RB 108 ( 11 amp).

EDIT , also just remembered reg box itself needs earthing as well as seperate earth terminal on box . However lack of one normally results in unregulated charge rather than no charge. I remember making a battery almost round once when learned this the hard way ! lOL
 

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I'm Not Jed Clampett
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iI you want to check your dynamo's output without the reg in circuit, try pulling the D and F wires off at the dynamo end, wire the D and F tabs on the dynamo together with baling wire or similar. When you start the start the car, you should see 20+ volts with a voltmeter from the D + F pair to earth when you rev the car a bit -don't jazz the motor or the dynamo voltage could run away. If that test comes up OK, there's some kind of fault with the reg or reg wiring -this is usually earthing as the voltage cut out coil (the one with the normally open contact) needs a good earth to operate as Kev says.
 
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