electric motor question

[Daryl]

undefined I need a dust collector in my shop. I only have a 100 amp service to my house so I have to watch the power a bit.I notice on the 2hp motor it draws 12amps @ 110 or 6amp @ 220. Is it logical to asume that on 220 it will use less power than on 110

[Homer]

undefined I need a dust collector in my shop. I only have a 100 amp service to my house so I have to watch the power a bit.I notice on the 2hp motor it draws 12amps @ 110 or 6amp @ 220. Is it logical to asume that on 220 it will use less power than on 110
The power used is the same in both cases, 12x110= 1320VA and 6x220= 1320VA.

What you do achieve by wiring a motor for 220V is it will draw half the current allowing you the potential to use smaller guage conductors. Also, for any given conductor size, the 220V motor will have less voltage drop in the lines (proportional to current) and will therefore give you a higher starting torque (a motor's starting current is very high). Not that it really matters for a dust collector.

In terms of your service you have two HOT legs with a maximum capacity of 100A on each. If you wire the motor as 110V you will draw 12A on one of the legs. If you wire the motor as 220V you will draw 6A on both of the legs.

If you are worried about the size of your service you need to do a demand load calculation. See the green & yellow squares at the top of the page for details.

Homer