25-01-2020, 09:52 PM
Over the last couple of days I've been playing with my dynamo. I rebuilt the dynamo months ago, having dismantled it 29 years ago! I used my best armature and fitted new higher resistance field coils and 2 new brushes, third brush removed.. Intention is to get an electronic regulator and run at 12volts, but I wanted to ensure the dynamo worked first.
Using 3 rectifier diodes out of a 1980s Lucas alternator I wired these to perform as a cutout. Next, powered up the field coils with engine running... increased revs... and yes it was charging! Over 12 amps and over 16 volts, so in danger of melting the armature.
Next I powered the field through a headlight bulb to reduce the current through the field windings. This was better but still too high.
Today I took away the headlight bulb and used a 12v 21 watt stoplight bulb. Yeah it charges about 6 amps. With a switch to turn this on and off, it will do for now as the rebuild continues. All good fun.
Using 3 rectifier diodes out of a 1980s Lucas alternator I wired these to perform as a cutout. Next, powered up the field coils with engine running... increased revs... and yes it was charging! Over 12 amps and over 16 volts, so in danger of melting the armature.
Next I powered the field through a headlight bulb to reduce the current through the field windings. This was better but still too high.
Today I took away the headlight bulb and used a 12v 21 watt stoplight bulb. Yeah it charges about 6 amps. With a switch to turn this on and off, it will do for now as the rebuild continues. All good fun.