What I have gathered so far;
500 HP motor trips out at the soft start with no rhyme or reason.
POCO serves the mill with a 2500kVA pad, 480Y/277 to an 800 amp main. That panel has a breaker feeding an AB soft start. When the soft start does trip out, the only way to get it back on is to kill the circuit and wait 15 minutes. This circuit was built 4 months ago and will run weeks at a time with no problems.
Today we connected a PQA at the soft start with the 500 HP motor running doing his job and recorded for 20 minutes. It did not trip today.
While we were connecting the meter, the drive rattled for a couple seconds like an old contactor failing. Nothing happened and it was just a couple seconds.
The first thing I see in the recording graphs is the currents are not close.
In the currents minimum column, L1-378, L2-464, L3-434.
In the currents maximum column, L1-462, L2-546, L3-514.
Voltage measurements look very good.
In the old days I would lean toward the motor.
Can a soft start do this to the currents? AB has been difficult to work with so far. This is a $20K+ drive.
Looking for a direction.
Thanks,
500 HP motor trips out at the soft start with no rhyme or reason.
POCO serves the mill with a 2500kVA pad, 480Y/277 to an 800 amp main. That panel has a breaker feeding an AB soft start. When the soft start does trip out, the only way to get it back on is to kill the circuit and wait 15 minutes. This circuit was built 4 months ago and will run weeks at a time with no problems.
Today we connected a PQA at the soft start with the 500 HP motor running doing his job and recorded for 20 minutes. It did not trip today.
While we were connecting the meter, the drive rattled for a couple seconds like an old contactor failing. Nothing happened and it was just a couple seconds.
The first thing I see in the recording graphs is the currents are not close.
In the currents minimum column, L1-378, L2-464, L3-434.
In the currents maximum column, L1-462, L2-546, L3-514.
Voltage measurements look very good.
In the old days I would lean toward the motor.
Can a soft start do this to the currents? AB has been difficult to work with so far. This is a $20K+ drive.
Looking for a direction.
Thanks,