My understanding is motor insulation is rated 200%?? of rated motor voltage. Is this true?
As a hobby to learn and understand motion I am retrofitting the controls on a Thermo CRS F3 robot which has a main power input of 77Vdc. My understanding is 77Vdc*.707 = 54.4Vac motor volts as the motor has no nameplate on it. I have a few Allen Bradley 120Vac 3-1398 and 1-2098 drives I would like to run these motors, but I am very concerned that even with light loading it will burn up the windings. So my simple math says 120/.707=169 Volts DC and if the motor insulation is 77 Volts DC with 200% rating is 154 Volts DC so I would surely burn them up as I have exceeded the insulation by 15 Volts. Is this true or in your opinion can I take the risk?
I have looked at APM-090-06 - COPLEY CONTROLS as it has Tamagawa Absolute serial encoders and Hall Sensors on the motor. I have requested a quote but expect the prices are a bit higher than DMM DYN2 AC Servo Drive which would require changing the encoders as DMM tech support said that would not work with Tamagawa. Is there another low voltage AC Servo drive that is low in price?
Lastly for fun I will tell you the plans. I am a ex Rockwell Engineer and have a L63 Controllogix in the house. I am wanting to control the robot arm with this controller and use RSView ME on a 1700 touch screen HMI. Copley has CANopen which can be interfaced from Ethernet IP using Anybus X-gateway – EtherNet/IP Adapter - CANopen Slave. So the robot can be sequenced through multiple positions and programmed using the most expensive teach pendant known.
The motor windings should be good for 600V+ so I don't think the voltage is going to be a problem as far as punching the insulation .....But, if you apply 170 volts to a motor designed for 70 volts, the current is going go to extreme. However the drive will protect itself from over current by reducing the voltage output or may just fault out. But is still capable of frying the motor due to overcurrent.
One thing that might work is to run the DC bus at 70 volts, but I don't know if the drive will read that as undervoltage and throw an error. It is also possible that the drive is programmable to limit the output voltage. It has been a long time since I have worked with those drives.
77Vdc AC Servo drive and motor Help
Reply with Quote
