mattsilkwood
Senior Member
- Location
- missouri
About a year ago we installed a big ammonia compressor with a 700hp 480vac motor.
It has three sets of 500mcm running to it about 75' from the drive.
The 500s are going to a tap box right above the peckerhead and makeup to 3 sets of 350 DLO cable.
The DLO then goes to the peckerhead and makes up to the motor leads using polaris taps.
About six months into service it bunrt the leads to B phase.
The drive meters and logs voltage and current among other things, everything looked fine on the log so we chalk it up to a loose connection.
I personally put it all back together, checked and rechecked every connection from the switchgear on down.
A couple months pass and it does the same thing. Same phase.
This time we took the motor off and sent it to the motor shop, they went through it and said it was in perfect condition.
This whole time the maintenance dept has been doing weekly PM which has consisted of shooting all the connections with a thermal gun while it is running and powering down and looking at all the connections for obvious signs of trouble. Everything has always been great.
Last night the drive faulted out because it lost its network connection, this is the first time it has done this.
Today we went in and checked everything and just like always everything looks fine.
We did put our recording meter on thinking the drives metering system isn't reading true.
Does anyone have any ideas about what could be causing this?
Im looking for any and all ideas, at this point we are chasing our tail.
It has three sets of 500mcm running to it about 75' from the drive.
The 500s are going to a tap box right above the peckerhead and makeup to 3 sets of 350 DLO cable.
The DLO then goes to the peckerhead and makes up to the motor leads using polaris taps.
About six months into service it bunrt the leads to B phase.
The drive meters and logs voltage and current among other things, everything looked fine on the log so we chalk it up to a loose connection.
I personally put it all back together, checked and rechecked every connection from the switchgear on down.
A couple months pass and it does the same thing. Same phase.
This time we took the motor off and sent it to the motor shop, they went through it and said it was in perfect condition.
This whole time the maintenance dept has been doing weekly PM which has consisted of shooting all the connections with a thermal gun while it is running and powering down and looking at all the connections for obvious signs of trouble. Everything has always been great.
Last night the drive faulted out because it lost its network connection, this is the first time it has done this.
Today we went in and checked everything and just like always everything looks fine.
We did put our recording meter on thinking the drives metering system isn't reading true.
Does anyone have any ideas about what could be causing this?
Im looking for any and all ideas, at this point we are chasing our tail.
