Issues with UPS power for motor starter
Issues with UPS power for motor starter
(OP)
One of my collegues has proposed to use designated UPS to feed all low voltage motor control relays, including the control power for the coils. One of major issues is, UPS will hold all the coils even though the main power is lost. Upon the recovery of the main power supply, all the motors will be started simutaneously and will cause excessive voltage dip in the system. This would cause overheating of motors. Any otehr potential issues other than what I described above. Appreciate it for any comments.





RE: Issues with UPS power for motor starter
I would not use a UPS for controls unless special circumstances demanded it. One possible use may be to power an AVR if a generator was being used as a poor man's VFD.
If I found that I had to supply a control scheme from a ups, I would add a power failure relay and a PLC. In the event of a power failure the PLC would drop out the motor starters and restart them in an orderly fashion.
If you are anywhere near Edmonton I will be coming in through Camrose on Monday.
Happy to buy you a coffee if we can connect.
Yours
Bill
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Issues with UPS power for motor starter
Use a sequential restart scheme. These used to be built using pneumatic timing relays, today would likely use a PLC
Use a DC control voltage and feed the motor starters from a tripping & control battery.
----------------------------------
If we learn from our mistakes I'm getting a great education!