Hello everyone,
Glycol pump, 7.5 kW, SINAMICS G120 with a CU240E 2 PN, run from TIA. Motor died Tuesday night and I put a new one in this afternoon, same frame, same nameplate numbers.
Drive runs and the current looks normal at about 12 A, but the flow is almost nothing and the return line is barely warm. I checked the motor data in the drive against the new nameplate and it matches, then I ran it from the BOP instead of the PLC and got the same, no flow.
One of the lads says the parameters get lost when you disconnect a motor, which I'm not sure about at all. Night shift, so there's nobody about to ask till morning. Is there anything on a straight motor swap I could have got wrong that still lets the drive pull a normal 12 A?
Did you look at the shaft? Which way against the arrow?
Didn't check. Pump coupling is under a bolted guard and it's a two person job, so I'm stuck till someone's about to hold the light.
The drive does not know which way the motor turns. It outputs U, V, W in the same sequence it always did. If the leads in the new motor's terminal box are landed differently from the old one, the motor turns the other way with the same current. Parameters are not lost by disconnecting a motor. Check rotation against the arrow.
If reversed: lock out at the supply, wait for the bus to discharge and prove the terminals dead before the box comes off, then swap any two of the three at the motor. Or set p1821 to 1 and the drive reverses without touching the wiring. I prefer the wiring, nobody finds a hidden parameter later.
Got the guard off first thing with a second pair of hands. Backwards, against the arrow.
Locked out, swapped U and V at the motor terminal box. Flow back, return line hot in ten minutes. The new motor's leads aren't numbered the way the old one's were, so the same three phases out of the drive turned it the other way. Two wires swapped and that was the whole job.
What bothers me is nothing on the drive said a word about it, no low flow alarm, and we've got no flow switch on that loop. Should have one. Thanks gunther, ed.
A bolted guard is why nobody checks rotation. Ours is the same, two people and a torch.