Mainswitch fuse overheating

Bobster · Aug 21, 2019

Agree with that it looks like a termination issue.

Loading issue would warm up the entire cable length, although I can't tell the differential between the 100deg measurement and the cooler section behind.

Very doubtful it's harmonics causing this issue, not with this amount of loading.

Skin effect isn't that prevalent at low loading, especially with parallel cables. An you have no neutral, this is where harmonics generally become a real problem in these smaller installations.

JSSE · Aug 21, 2019

You have not lost a core on one of the parallel supply's have you

timbobelfast · Aug 21, 2019

Could be possible that the magnets have lost some of their magnetism? Does it run at normal temperature at lower speeds? Has the VFD frequency been changed or adjusted? Does the compressor get regular mechanical servicing?

Eire79 · Sep 14, 2019

Strima said:
That appears to be hotter where the cable terminates into the ring crimp on L3, have you tried re-terminating?

Yes we re terminated and it still existed then moved it to spare 630 a Sw beside and it still followed.
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JSSE said:
You have not lost a core on one of the parallel supply's have you

No all intact
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timbobelfast said:
Could be possible that the magnets have lost some of their magnetism? Does it run at normal temperature at lower speeds? Has the VFD frequency been changed or adjusted? Does the compressor get regular mechanical servicing?

The vsd varies automatically to set point on compressor but we since found a mechanical issue, the on load offload valve was faulty so compressor was flat out trying to reach a set point but dumping half it's air. Since this has been fixed the compressor is now running probably at 75 % capacity and loading on cables has reduced. Also we got a power quality audit done and I'm waiting for the report although it appears there was aprox 18% current harmonics on it . I'll let u know the outcome.