High bus voltage trip. Line voltage remains constant at 479, 480, 481. During operation bus voltage remains steady about 645vdc. It trips at start up. It seems as the scr's are charging the capacitors too fast during pre charge, but i have nothing to prove it. Any suggestions?
“VSD – HIGH DC BUS VOLTAGE”
The VSD’s DC link voltage is continuously monitored
and if the level exceeds 745VDC, a Bus Over-Voltage
shutdown is initiated. If this shutdown occurs, it will be
necessary to look at the level of the 460VAC applied to
the drive. The specified voltage range is 414 to 508VAC.
If the incoming voltage is in excess of 508VAC, steps
should be taken to reduce the voltage to within the
All detailed info. would be helpful like a full M/N & S/N
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Does it reset and start after having already charged the capacitor bank?
It would reset and make it through the pre-charge and start. It would not trip all the time. It has not tripped in two days. I am thinking a bad connection in one of the plugs, because after disconnecting and reconnecting every plug in the vsd it has not had any problems. The only troubleshooting steps in the manuals I have said the same thing about the incoming voltage which was steady and the harmonic filter dc bus voltage was not high.
I had the problem your describing and it ended up being that the wires that land on tb1 tb2 and tb3 on the trigger board were crossed up when the board was changed. On a YK i think it should be 67a-t1 68a-t2 and 69a-t3 not looking at a diagram. The reason it starts after recycling is because it doesnt have to go through precharge sense it already is charged and didnt have sufficeint time to discharge. Be very careful that speed drive is dangerous to an unqualified or untrained person
Thanks for the input and the note on safety.
Have you checked the Bleed off resistors on the bottom of the drive, they should be 2.4k ohms, it says on it what it is suppose to be. These resistors are not just for bleeding the capacitors down, they also balance the dc bus voltage. If the resistors are bad it could cause this alarm.