Fordean
Senior Member
- Location
- New Jersey
- Occupation
- Electrical Contractor
I have 3 phase 460volt 7.5 HP motor. 480 fed. I have two complete different setups.
#1 Has 5.5, 5.2, 5.6 amps per phase. THis setup is good one.
#2. Has 5.2, 4.3, 3.5 amps. Swapped out motor thinking this was issue but not. This unbalance 3.5 divided by 5.2 it about 35 percent differential. Causing Motor Logic to Trip. Square D says MOtor logics trips anywhere the amperage exceeds 15 or 20 percent indifference.
I finally megger the wires underground. They were deemed bad by megger. I think wires are crushed underground ( but not Direct short) due to the short run and I cant pull the wires out of conduits. from either side (couldnt move a inch) Pipe is 1 in. RGS. 25 feet with only two 90 I believe. Notice RGC is Rotting In other jobsites. that are installed over 35 years in Concrete or underslab.
Why would Pinch cause less amps. If that the case.
I seen this before above ground. Guys tightning clamps to tight not seemingly pierceing insulation. But still Causing trips.
#1 Has 5.5, 5.2, 5.6 amps per phase. THis setup is good one.
#2. Has 5.2, 4.3, 3.5 amps. Swapped out motor thinking this was issue but not. This unbalance 3.5 divided by 5.2 it about 35 percent differential. Causing Motor Logic to Trip. Square D says MOtor logics trips anywhere the amperage exceeds 15 or 20 percent indifference.
I finally megger the wires underground. They were deemed bad by megger. I think wires are crushed underground ( but not Direct short) due to the short run and I cant pull the wires out of conduits. from either side (couldnt move a inch) Pipe is 1 in. RGS. 25 feet with only two 90 I believe. Notice RGC is Rotting In other jobsites. that are installed over 35 years in Concrete or underslab.
Why would Pinch cause less amps. If that the case.
I seen this before above ground. Guys tightning clamps to tight not seemingly pierceing insulation. But still Causing trips.