Cut out

[morrisminor]

I've just had my dynamo rebuilt because it was squeaking, the ignition light was staying on and the ammeter was showing discharge . Put it all back together,  still the same.  The cut out points are open when the car is off, when I start it they stay open.  I've read somewhere that the points can be adjusted ?
Any suggestions from you knowledgeable people ?
Thanks all, any ideas please explain in simple terms !!

[Howard Wright]

Hi

I’ve replaced the cutout with a diode.  The Magnetoguys  https://www.themagnetoguys.co.uk/smart-diode-cut-out sell one at a reasonable price and it can be hidden in the cutout box!

Cheers

Howard

[David Stepney]

First thing to do is to check that the dynamo is charging. Connect the D and F terminals together and then connect them to a voltmeter with the other lead earthed. Use an analogue instrument, as the electronic sort don’t like the noise the ignition produces. Start the engine and note the voltage as you rev it up. It should rise to about 8 to 10 volts. If it does, then the problem will be it he cutout.check that the cutout is wired properly and is earthed. There is a recent thread concerning cutouts.

[Tony Griffiths]

Hi Howard. Might you be able to expand on the fitting - the type of cutout fitted and how the diode was wired in?

[Howard Wright]

Hi Howard. Might you be able to expand on the fitting - the type of cutout fitted and how the diode was wired in?

Hi Tony

The website is pretty self explanatory.  I just used a ‘chocolate box’ connector to wire it in.  


Cheers

Howard

[Bob Kneale]

It may be something as simple as the dynamo has lost its residual magnetism. Try 'flashing' the dynamo with the engine running briskly and touch one end of a wire from the battery connection on the starter motor and the other end on the 'F' terminal briefly. you should notice the cutout points closing. Remove the wire and rev the engine a little more and you should be rewarded with a charge showing on the ammeter. The ignition light should then go out. It will take less time to carry this out than it has taken me to type this!
Good luck
Cheers
Bob

[morrisminor]

I've tried flashing the dynamo, no joy, the cut out points didn't close nor the ignition light go out and I've tried running the car putting a wire inbetween d and f using a ammeter one to the d and f and one to earth,  it didn't show a reading ?
What do you guys think ?

[Tiger]

Sounds like no output from the Dynamo
Is it possible to get help from the Dynamo rebuilder ?

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You don’t say your location I am sure if one of the seveners is near we could help!

[andrew34ruby]

I've tried flashing the dynamo, no joy, the cut out points didn't close nor the ignition light go out and I've tried running the car putting a wire inbetween d and f using a ammeter one to the d and f and one to earth,  it didn't show a reading ?
What do you guys think ?

I think you need the help of someone who understands.

Joining D to F on the dynamo sends all the power generated through the feild windings, but they should have enough resistance to cope. But joining an ammeter from D and F to earth is likely to simply destroy the ammeter. An ammeter has very little resistance so you basically introduced a dead short. This might damage the dynamo and/or destroy the ammeter. You should have connected a voltmeter to earth.

[morrisminor]

I meant an analogue volt meter