Stewart Corman
3rd June 2008, 16:30
I am Ohms law challeged , but I pick up enough to be dangerous.
Was talking to my electronics Guru George about a controller scheme for my wind turbine, and he gave me some good ideas. Primarily it was his conclusion that even tho the PM servo gives high voltage 3 phase wild AC, that the best option is to transmit juice to the house using three strands, but immediately convert to DC and go from there. We are looking at using a PWM scheme to keep unloaded until a certain voltage is obtained, then increase the PWM until full load is applied at nominal operating point ...details will follow later, as I have several interested parties evaluating the specifics and I am looking for feedback. But I digress ......
The conversation switched to the 1/3hp AC squirrel blower in my hot air furnace ducting ...George claimed that these AC motors have pitiful efficiency in the range of 30% and to replace with a DC motor would be >2x improvement. I know that the motor is rated at 115v/5.5amp, but admittedly I need to attach the Kill-A-Watt to see what it is really cranking at the pulley rotation currently used. When I burn firewood, this circulation blower is on about 12hr/day.
Once I procure a DC motor, then the PWM scheme above could be a low loss means to drive the DC motor and possibly slow it down as well.
I was planning on measuring the rpm of the current setup and matching that rpm with the DC motor to see the energy benefit as read on the Kill-A-Watt. Then see how much juice is saved at reduced rpm.
Any comments and experience would be appreciated.
Stew Corman from sunny Endicott
Was talking to my electronics Guru George about a controller scheme for my wind turbine, and he gave me some good ideas. Primarily it was his conclusion that even tho the PM servo gives high voltage 3 phase wild AC, that the best option is to transmit juice to the house using three strands, but immediately convert to DC and go from there. We are looking at using a PWM scheme to keep unloaded until a certain voltage is obtained, then increase the PWM until full load is applied at nominal operating point ...details will follow later, as I have several interested parties evaluating the specifics and I am looking for feedback. But I digress ......
The conversation switched to the 1/3hp AC squirrel blower in my hot air furnace ducting ...George claimed that these AC motors have pitiful efficiency in the range of 30% and to replace with a DC motor would be >2x improvement. I know that the motor is rated at 115v/5.5amp, but admittedly I need to attach the Kill-A-Watt to see what it is really cranking at the pulley rotation currently used. When I burn firewood, this circulation blower is on about 12hr/day.
Once I procure a DC motor, then the PWM scheme above could be a low loss means to drive the DC motor and possibly slow it down as well.
I was planning on measuring the rpm of the current setup and matching that rpm with the DC motor to see the energy benefit as read on the Kill-A-Watt. Then see how much juice is saved at reduced rpm.
Any comments and experience would be appreciated.
Stew Corman from sunny Endicott