28-12-2021, 09:29 AM
Hi Tiger
A common test method is to strap the Field input to the Dynamo output. However, without a battery connected to cap the voltage at 6 to 7 volts, the output can rise to high levels as the dynamo speed is raised. This risks cooking the field coils if you keep going for too long.
As Bob hints, the problem with a bulb-only load is that a cold bulb has a very low resistance compared to when it's burning bright. The dynamo output may never build up and get "off the ground"
An alternative method is to run the field completely independently from a 6 volt battery. It will draw 2 or 3 amps. I suggest the load on the Dynamo output is one or more 6V bulbs in parallel, with a total rated wattage of say 30 to 60 watts. This will give a realistic load for testing.
A common test method is to strap the Field input to the Dynamo output. However, without a battery connected to cap the voltage at 6 to 7 volts, the output can rise to high levels as the dynamo speed is raised. This risks cooking the field coils if you keep going for too long.
As Bob hints, the problem with a bulb-only load is that a cold bulb has a very low resistance compared to when it's burning bright. The dynamo output may never build up and get "off the ground"
An alternative method is to run the field completely independently from a 6 volt battery. It will draw 2 or 3 amps. I suggest the load on the Dynamo output is one or more 6V bulbs in parallel, with a total rated wattage of say 30 to 60 watts. This will give a realistic load for testing.