converting motors to voltages used outside the US
converting motors to voltages used outside the US
(OP)
I have a 240volt 60HZ motor, I believe it is a 5 horse, however the name plate states it is "Special" and is continuous duty . The motor goes on an air compressor that is in Togo Africa. When I received it the start capacitor was blown and it appeared that the start windings had gotten warm. The power in Togo is 230volt 50hertz. It is my understanding that to keep the motor from overheating one would have to bring the voltage down to 80percent of the nameplate, so this was my first thought. I have not ever dealt with power in other countries and I am not how it is used. I was looking into voltage converters, but when it started to talk about converting from 110/120 to 230/240 I got a bit confused. Here in the US when you are speaking of 240 single phase you are speaking of 2 hot wires. So, when you are speaking of 230 in Togo Africa are you still speaking of 2 wire single phase?





RE: converting motors to voltages used outside the US
Check out the FAQ: FAQ237-1224: Motors: Changing between a 50 and 60Hz supply. which discusses them all.
The biggest problem with an air compressor is starting. You have a reduced starting toque that can dial-up excessive starting times that blitzes the windings and the capacitor. Often your system can't get up to speed so the centrifugal start switch can't transition out of start and this toasts everything - the very first time.
You need a way to reduce the speed at which the switch transitions the start winding out. Not easy to do...
Keith Cress
kcress - http://www.flaminsystems.com
RE: converting motors to voltages used outside the US
RE: converting motors to voltages used outside the US
It's a possibility worth exploring. Carefully.
RE: converting motors to voltages used outside the US
Mike Halloran
Pembroke Pines, FL, USA
RE: converting motors to voltages used outside the US
As itsmoked says, starting may be an issue.
I would try doubling the size of the starting capacitor. I was in a situation where 1/2 HP motors were ordered instead of 3/4 HP motors and the motors stalled instead of starting. The time and place was such that if the 1/2 HP motors could not be used they had little or no value. With nothing to lose we doubled the size of the starting caps and the motors have been starting well for years now.
If the motor doesn't start immediately disconnect it and go to plan B.
Plan B: You may also try reducing the size of the pulley on the motor.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: converting motors to voltages used outside the US
I expect this someone will just install a new 50Hz motor. The compressor will run at 83% speed.
RE: converting motors to voltages used outside the US
Description
5hp 4kw 220-250v Variable Frequency Drive Inverter VFD with Extremely Strong Anti-jamming Capability
http://www.amazon.com/220-250v-Frequency-Extremely...
Inpute Voltage: 220±15% (+/- 33 volts, so 187 to 253 VAC) (We also stock 380±15%, please contact us for item stock)
Output Voltage: 208 to 240VAC (analogous to Input Voltage)
Input Frequency: 48 to 63 Hz
Outpute Frequency: 0 to 400 Hz
Inpute Phase: 1 or 3 phase as you like
Outpute Phase: 3 phase
RE: converting motors to voltages used outside the US
I should expand on what I wrote last time and add that the person could also change the pulley ratio to bring the compressor back to full speed.