workshoprat
Plastic
- Joined
- Dec 8, 2012
- Location
- Bois D Arc MO
Hey guys im trying to do a static phase converter for a harrison m400 10 hp lathe motor. I am having great trouble getting this to a usable configuration. Its easy enough to use start and run capacitors to start and run the motor. It is clutched so it starts in freewheel mode not much of a starting load. I can get it where all legs are balanced within about 4 volts of each other when running. I have a magnetic relay and can get it to work as an auto start to kick out the start caps when it gets up to speed with a 600 ohm resistor in line.
First problem. The coil on my relay draws enough current it will blow out a 500 ohm 5 watt resistor in a short amount of time. It has a 120v coil. Im pretty sure i need a 220v coil relay. Its hard as heck to find an affordable 220v coil relay with nc contacts large enough to handle the amp load of the caps and motor draw.
Second problem is that when a load is applied its enough to throw everything out of phase and stall the motor. It seems running free wheel and under load are two different things lol. I can add more run capacitors to where this is lessened but the more i add the worse the leg voltage balance gets and causes other issues.
I have never had a phase converter design fight me this bad. Of course the largest motor i have tried this on up untill now was a 2 hp motor.seems once you get up to the 10hp range everything changes and its a whole different ball game.
Do you think it would make a difference if the motor is wired in a wye or delta pattern for this application?
First problem. The coil on my relay draws enough current it will blow out a 500 ohm 5 watt resistor in a short amount of time. It has a 120v coil. Im pretty sure i need a 220v coil relay. Its hard as heck to find an affordable 220v coil relay with nc contacts large enough to handle the amp load of the caps and motor draw.
Second problem is that when a load is applied its enough to throw everything out of phase and stall the motor. It seems running free wheel and under load are two different things lol. I can add more run capacitors to where this is lessened but the more i add the worse the leg voltage balance gets and causes other issues.
I have never had a phase converter design fight me this bad. Of course the largest motor i have tried this on up untill now was a 2 hp motor.seems once you get up to the 10hp range everything changes and its a whole different ball game.
Do you think it would make a difference if the motor is wired in a wye or delta pattern for this application?