There was a short on phase A to B on one set of parrallel motor leads and and short on B to C on the 2nd set of motor leads. We are sending the motor to a repair shop to investigate what exactly happened in the motor.
This is what was recorded in the field:
First set of parallel wires.
A...
Attached is a picture of welded contacts with phase C on the right burnt up on West 480V LVMCC.
Prior to finding this, the West LVMCC main breaker tripped and the MCC lights went out (lights are on the MCC with these contacts). The East 480V LVMCC main breaker tripped as a result of...
I have attached another picture of the contactors. These are the same contactors used when we had undersized cable to the contactor and motor. The metal seems to be still melting when we have the 2 runs of 350 MCM run to the motor. Is this wear typical of contactors of this size or do you...
We did have breaker trips. The vendor set the magnetic trip on its highest setting which is 6300 amps which is out of the 13 x FLA range early on in the startup. I having the electrician reduce the trip setting to 5400 amps which is the 2nd highest setting and will be within the 13 x FLA range.
There is no binding.
We will clean the arc chutes. The client thinks that the contactor appearance looks abnormal. A Siemens tech was on site today and mentioned that the contactors looked pretty bad. I believe the motors that were run the most when we had only one run of 350 MCM would...
I have attached a picture of the contacts. Do these look normal? http://files.engineering.com/getfile.aspx?folder=083564d1-bc78-4925-b804-58584810f4c8&file=image009.jpg
Since we added the second run of 350 MCM, we have not experienced any welding.
The disconnect was opened before the contacts were pulled apart.
The vendor only supplied the Motor starters and contactors. The one run of 350 MCM was due to a distribution error when the drawings where sent to...
We have a motor control center (MCC) that has 8 - 480V Nema size 6 starters (FVNR). These starters control 8 - 400 HP motors with a KVA code of 'G' and is high efficiency rated. The motors are started Across-the-line (480V). The Full Load Current (FLA) for a motor is 418 amps and has a locked...
