Can anyone confirm the basic testing of a dynamo on the bench?
I have bridged the two terminals and connected the wires to the Positive side of a battery. By touching the Neg from the battery to the case the dynamo will motor in the correct direction.
But by driving the dynamo with my electric drill, and with a bulb connected by the bridged wires and earthed against the case....I get no illumination???? Ron
Your electric drill probably wasn't going fast enough! I can test the armature with a growler FOC if you like, but on the whole if the armature dosen't appear damaged in any way, and dosen't smell burnt out they will usually go again. If it appears a bit poor at motoring it could be a brush problem (ie not making a very good connection on the commutator) They don't motor too well as the windings are designed for working as a dynamo, not an electric motor. You could try putting the gear on the end and try putting it up to something that revolves faster, sometimes I test mine on my polisher, by just putting the gear against the polishing mop
Even so, if you bridge the 2 terminals with a bulb holder and bulb and spin it fast enough it should light it up. Just as a rough guide the field coil should have a resistance of about 3 ohms, most of the manuals presume you don't have an AVO meter at home as they were printed in the days when they were quite hard to get hold of. Try disconnecting the wires on the field coil and check it isn't earthed out. I'd have thought the problem lies with the MCR1 if it lights or motors
The dynamo does not need voltage flowing through the field windings to start it charging, there is always a small amount of magnetisim in the pole piece that the field windings are attached too.This enables the dynamo to produce enough current to activate the cutout in the regulator and so put current (regulated) through the field windings and so produce more voltage. if you are testing the dynamo by joining D&F together on the side of a bulb use a 12 volt bulb as a 6 volt dynamo will produce about 18 volts before the solder throws off of the commutator if you spin it fast enough.
