- Joined
- Feb 10, 2009
- Messages
- 2,978
With both the DC shunting regulator and the AC shunting regulator (which you are calling “shorting”), there is an AC current flowing through a circuit.
The AC shorting regulator can avoid some of the heat buildup in the reg/rec box, because the current does not have to pass through the rectifier. Rectifiers have resistance and voltage drop, so they get warm when they pass current.
The DC shunting regulator requires the AC current to pass through the rectifier as well as the regulator transistor. That could generate more heat in the reg/rec box than the AC shorting type.
I used a lot of “can” and “could” because it must depend on circuit design and component specs.
If the AC shorting type has less resistance to the AC current than the DC shorting type, then it could allow the AC current to be greater. That current goes through the stator coils, so there could be more heat.
The above may show no disagreement with what Gtiller said. On the other hand, my 12 A stator shows a resistance value so low that I can’t easily see it on a digital meter. It’s a sort of erratic 0.1 ohm.
Using Ohm’s Law (V=IR), voltage drop across the stator is 12 x 0.1 = 1.2 volts.
Power is W=IV. 12 x 1.2 = 14.4 W.
14.4 watts is less power than a brake light bulb.
Is there physics that says my 0.1 ohm is not valid once magnets start spinning past coils? I wouldn’t be all that surprised. Where’s Milly Henry when you need her!
I found it interesting that the measured AC current on my own bike was the same (reading an analogue meter) whether the lights were on or off.
The AC shorting regulator can avoid some of the heat buildup in the reg/rec box, because the current does not have to pass through the rectifier. Rectifiers have resistance and voltage drop, so they get warm when they pass current.
The DC shunting regulator requires the AC current to pass through the rectifier as well as the regulator transistor. That could generate more heat in the reg/rec box than the AC shorting type.
I used a lot of “can” and “could” because it must depend on circuit design and component specs.
If the AC shorting type has less resistance to the AC current than the DC shorting type, then it could allow the AC current to be greater. That current goes through the stator coils, so there could be more heat.
The above may show no disagreement with what Gtiller said. On the other hand, my 12 A stator shows a resistance value so low that I can’t easily see it on a digital meter. It’s a sort of erratic 0.1 ohm.
Using Ohm’s Law (V=IR), voltage drop across the stator is 12 x 0.1 = 1.2 volts.
Power is W=IV. 12 x 1.2 = 14.4 W.
14.4 watts is less power than a brake light bulb.
Is there physics that says my 0.1 ohm is not valid once magnets start spinning past coils? I wouldn’t be all that surprised. Where’s Milly Henry when you need her!
I found it interesting that the measured AC current on my own bike was the same (reading an analogue meter) whether the lights were on or off.