MauledByBears
Plastic
- Joined
- Apr 27, 2017
Hi,
I recently installed a VFD to convert 110V 1ph to 220V 3ph for a 10" lathe.
I gave it 10% torque compensation at the low end so I can get it started and run at low speeds (20Hz is the minimum), and it starts great and runs with plenty of torque. As I increase the output frequency, I get pretty normal behavior (speed and torque increase) until about 40-45Hz where the motor gets a little louder, the spindle decreases in speed, and I get so little torque I can stall the spindle with my hand. This effect is exacerbated up though 70Hz which is the max frequency I set.
This freaked me out, so I immediately cut power. I didn't want to let it run long enough to trip an error on the VFD and risk burning out the motor. After sleeping on it, I'm guessing that I have a voltage drop at the 110V outlet and that the increased current draw at 40Hz+ is causing a drop in voltage at the input, and a proportional drop at the output, resulting in the poor torque and speed outputs. (The electrician who wired my house was, I'm convinced, actually two children stacked inside a trench-coat with a pair of lineman's pliers).
When I get home I'll be able to test my theory with a DMM across the VFD terminals, but does anyone have any ideas in the meantime for things to check? I'd rather not let the VFD fault to get a diagnosis, I just bought it and the risk of letting out the magic blue smoke is making me wary.
Thanks!
Sam
I recently installed a VFD to convert 110V 1ph to 220V 3ph for a 10" lathe.
I gave it 10% torque compensation at the low end so I can get it started and run at low speeds (20Hz is the minimum), and it starts great and runs with plenty of torque. As I increase the output frequency, I get pretty normal behavior (speed and torque increase) until about 40-45Hz where the motor gets a little louder, the spindle decreases in speed, and I get so little torque I can stall the spindle with my hand. This effect is exacerbated up though 70Hz which is the max frequency I set.
This freaked me out, so I immediately cut power. I didn't want to let it run long enough to trip an error on the VFD and risk burning out the motor. After sleeping on it, I'm guessing that I have a voltage drop at the 110V outlet and that the increased current draw at 40Hz+ is causing a drop in voltage at the input, and a proportional drop at the output, resulting in the poor torque and speed outputs. (The electrician who wired my house was, I'm convinced, actually two children stacked inside a trench-coat with a pair of lineman's pliers).
When I get home I'll be able to test my theory with a DMM across the VFD terminals, but does anyone have any ideas in the meantime for things to check? I'd rather not let the VFD fault to get a diagnosis, I just bought it and the risk of letting out the magic blue smoke is making me wary.
Thanks!
Sam