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+--- Thread: Dynamo Woes (/showthread.php?tid=6156)
Dynamo Woes - Martin Baker - 23-05-2021
I have just rebuilt a dynamo following realisation that the field winding solder joint had failed.
Everything seems to test OK (commutator segments, field winding resiatances etc.) and it runs as a motor. However in the car it fails to charge even after flashing it and reversing field windings.
Admit I am at a loss. Any bright suggestions?
RE: Dynamo Woes - "Slack Alice" Simon - 23-05-2021
Cut out not closing?
RE: Dynamo Woes - Nick Salmon - 23-05-2021
Given my current (no pun intended) tribulations are you sure ammeter is being truthful?
RE: Dynamo Woes - Bill Dixon - 23-05-2021
To check that the dynamo is giving an output remove the leads from the D and F tags , then connect a link across DAnd F tags, take a 12 volt head lamp bulb, and connect it between the link and the dynamo earth. Start the engine slowly increase the revs if the bulb lights up brightly the dynamo is giving an output.
RE: Dynamo Woes - Bob Culver - 23-05-2021
Not sure re what is meant by "reversing the field windings" but literally there is only one correct way. The tiny initial field current must reinforce the magmetism; if it counters will not start to generate whatever the polarity.
RE: Dynamo Woes - Martin Baker - 24-05-2021
Pleased to report problem sorted. On checking with insulation tester, I found a short between armature windings and the shaft.
Swapped with another armature and all sweetness and light! Really strange that it motored without problem??
RE: Dynamo Woes - Dave Mann - 24-05-2021
I've come across a few dynamos which motor but won't generate.