transition from Genset to Utility
transition from Genset to Utility
(OP)
Like to hear some ideas, if ya got em.
3phase 480v 200 hp well motor, operated via soft start controller. During the monthly back up genset test, when the transfer switch changes from generator back to utility, the motor shuts off. It then goes into a pre-set lock out at the plc, so that the motor shaft can "backspin"..with out damage.After 2 minutes, the motor starts again.
I've seen this happen on other back up systems, with big motors. The transition is "seamless" to computers and other machines, but with big motors they turn off and have to be reset.
Would changing the delay from genset to utility solve this?..or can it be?
At another well site, 1 well motor same size as above, along with 2 " booster pumps", are backed up via the same type of system. Same brand transfer switch, same programming on the plc.
BUT...the starters are VERY old, Clark Controllers. ( i'd say about 50 years old) And when they retransfer, none of the motors, even the 200hp motor gets bumped offline. I think the starters on the old system are not sensitive to the voltage fluctuation.
Im in the process of trying to dig up info on the soft start Westinghouse controllers, to see what can be done.
HP
3phase 480v 200 hp well motor, operated via soft start controller. During the monthly back up genset test, when the transfer switch changes from generator back to utility, the motor shuts off. It then goes into a pre-set lock out at the plc, so that the motor shaft can "backspin"..with out damage.After 2 minutes, the motor starts again.
I've seen this happen on other back up systems, with big motors. The transition is "seamless" to computers and other machines, but with big motors they turn off and have to be reset.
Would changing the delay from genset to utility solve this?..or can it be?
At another well site, 1 well motor same size as above, along with 2 " booster pumps", are backed up via the same type of system. Same brand transfer switch, same programming on the plc.
BUT...the starters are VERY old, Clark Controllers. ( i'd say about 50 years old) And when they retransfer, none of the motors, even the 200hp motor gets bumped offline. I think the starters on the old system are not sensitive to the voltage fluctuation.
Im in the process of trying to dig up info on the soft start Westinghouse controllers, to see what can be done.
HP






RE: transition from Genset to Utility
Mike
RE: transition from Genset to Utility
HP
RE: transition from Genset to Utility
Mike
RE: transition from Genset to Utility
HP
RE: transition from Genset to Utility
Mike
RE: transition from Genset to Utility
RE: transition from Genset to Utility
Without a closed transition system, it is impossible to synchronize the sources, correct?
HP
RE: transition from Genset to Utility
As you know, if you have an open transition, there's no need to synchronize between sources. I don't believe you can correct the issue if your system is such that you have standby gen's, and you transition from utility to gen. However, you could have closed transition from gen. back to utility, although, you'd have to see if your bracing/AIC ratings are such that you can parallel both utility and gen. and provide a sync. circuit (which should be available via the ATS).
Mike
RE: transition from Genset to Utility
From and ASCO manual:
INPHASE MONITOR FOR MOTOR LOAD TRANSFER
Inphase monitoring logic controls transfer and retransfer
of motor loads, so that inrush currents do not exceed
normal starting currents. It avoids nuisance tripping of
circuit breakers and mechanical damage to motor
couplings.
RE: transition from Genset to Utility
So it would seem that an adjustment in the delay to neutral setting should take care of this problem.
HP