Testing Motor Overloads
Testing Motor Overloads
(OP)
Hi Sparkies,
This may be a stupid question, but how would you test an overload device on 60 HP motor? Unless you substituted the existing load with a load that draws more Amps, I don't see how you would confirm your new OL picks up on overload. It seems to me that you'd set your overload device based on your calculations, and hope that it does its job.
Regards,
CE
This may be a stupid question, but how would you test an overload device on 60 HP motor? Unless you substituted the existing load with a load that draws more Amps, I don't see how you would confirm your new OL picks up on overload. It seems to me that you'd set your overload device based on your calculations, and hope that it does its job.
Regards,
CE





RE: Testing Motor Overloads
You don't test with a load at line voltage. An overload relay responds to current and so is tested with a calibrated current at a low voltage.
Bill
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"Why not the best?"
Jimmy Carter
RE: Testing Motor Overloads
RE: Testing Motor Overloads
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Testing Motor Overloads
https://us.megger.com/products/relay-and-protectio...
Why are you asking? Do you have a particular instance that is making you suspect that your OLs are not tripping correctly? Current injection testers are very expensive and require training because they can be dangerous, typically bought and used by people doing this a lot such as electrical testing companies. If yours is a one-off thing, I suggest calling one. If you are in North America, look for a local NETA (National Electrical Testing Assoc.) provider.
" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden
RE: Testing Motor Overloads
If you search for breaker test set you can find other similar test sets from other manufacturers.
RE: Testing Motor Overloads
Care to explain the reasoning for the testing?
Maybe this is a Planned maintenance issue?
RE: Testing Motor Overloads
if you do not have any of the power sources and the requirement to test the overcurrent relay, you can reduce relay setting and expect a switch off breaker at the rated current of the motor. Most over-load relays work with double current in range between 50 and 100 seconds. Pay attention because motor exclusion may cause some problems in process.
RE: Testing Motor Overloads
Thanks!
RE: Testing Motor Overloads