Maintenance Man
Member
Hi to all,
Last week we had a frequency drive that runs a conveyor belt keep tripping out with a loss phase fault. The frequency drive is 3 phase for a 480 v motor with a gear box. The problem would occur when the line ran for a while then would trip the frequency drive with a phase loss error. The frequency drive, motor and wires were changed by the other crew in which it did not solve the problem. I changed the transformer used to drop the 480v to 120v for the control circuit. The 3 phase comes off the bus bars in the MCC panel and goes to the main breaker then from the bottom of the main breaker; it goes to the top of the frequency drive in which 2 of the leads goes to the transformer for the control circuit. Because the problem would occur after the belt was running for a while made me think there was a problem with the transformer shorting across the windings when it got heated up causing the frequency drive to think it had lost a phase in which it would shut down with the phase loss error. My question is ,if the way I am thinking about this it correct about the transformer causing the phase loss or was there something else going on with the transformer. All I know is that the problem went away when I had put in the new transformer. Any feedback would be greatly appreciated. Thank you very much for you help.
Sincerely
Maintenance Man
Last week we had a frequency drive that runs a conveyor belt keep tripping out with a loss phase fault. The frequency drive is 3 phase for a 480 v motor with a gear box. The problem would occur when the line ran for a while then would trip the frequency drive with a phase loss error. The frequency drive, motor and wires were changed by the other crew in which it did not solve the problem. I changed the transformer used to drop the 480v to 120v for the control circuit. The 3 phase comes off the bus bars in the MCC panel and goes to the main breaker then from the bottom of the main breaker; it goes to the top of the frequency drive in which 2 of the leads goes to the transformer for the control circuit. Because the problem would occur after the belt was running for a while made me think there was a problem with the transformer shorting across the windings when it got heated up causing the frequency drive to think it had lost a phase in which it would shut down with the phase loss error. My question is ,if the way I am thinking about this it correct about the transformer causing the phase loss or was there something else going on with the transformer. All I know is that the problem went away when I had put in the new transformer. Any feedback would be greatly appreciated. Thank you very much for you help.
Sincerely
Maintenance Man