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Advice needed: hp pump trips breaker

S

soonermajic

Well-known member
Our 3 phase breaker keeps tripping, each time the big 25hp motor kicks on Cat 3535.
Electrician said breaker & motor bad...? Put on new breaker had 25hp motor tested. Said amps, rpms, & ohms all good = motor was good.
Put motor back on, & immediately starts tripping new breaker.

Any advice...?
Possible wire shorting from breaker to motor?
Could 25hp motor actually be bad, due to bad amps from previously bad breaker?
 
Get a clamp-on amperage meter. You'll need one that reads up to at least 400 amps. I carry one that reads to 600, Klein, was $30 at Home Depot.
 
soonermajic said:
Could 25hp motor actually be bad, due to bad amps from previously bad breaker?
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I don’t think a bad breaker would cause a bad motor unless it was not tripping. Since it was tripping, I would think that if your motor was bad, it had a problem on its own, independent of the breaker.
 
Electrician said it was getting bad power forna while, cause water had been dripping inside breaker box. He thinks that is what has damaged the motor (if it in fact is dsmaged).
 
Does the motor spin up at all or does the breaker trip instantly?

Water dripping into breaker box theory doesn't make sense unless it caused a physical problem in the box. Maybe pull the new breaker out and look at the connections behind it.
 
If motor tested good and was not hooked to a pump during test I’d consider looking at the pump end of things. I had a similar issue with a 3535 and it ended up being a failing pump causing to much heat on the motor
 
Pressure set too high? Plugged nozzles causing increase? Nozzle change to smaller ones? Solenoid not opening quick enough, causing pump to deadhead?
 
If it's load related, you should be tripping a overload and not a breaker( if it's set up properly). As mentioned, you need to check your contactor and amperage and possibly find another electrician. Also, weak control voltage to the contactor can cause the contactor to make a weak connection or buzz which can cause heavy inrush currents that can trip a feed breaker.
 
MEP:I don't think it spins @ all, just trips immediately (pretty sure).
MC30: didn't think about it being a 3535.
KarlB: electrician said possibility
IB: no nozzles clogged or deadheading
JG: good advice & think they have looked @,that. Can't get any other electricians, cause building up @ lake is INSANE! 1 of busiest in entire US!
 
Etowah
soonermajic said:
Can't get any other electricians, cause building up @ lake is INSANE! 1 of busiest in entire US!
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You’re electrician needs to be fired. This diagnosis should be fairly simple especially if the condition occurs every time. If it was an occasional trip issue it would be more difficult to diagnose. If the electrician can’t perform this simple test he is notqualified and is stealing your $$.
I agree with others get a clamp on amp meter and check each legs amperage. Check voltage for each leg before continuing.
I’d start by switching the breaker off and disconnecting the wires from the motor contactor to the motor. Switch breaker on. Does the breaker trip? No. Push motor contactor in manually. Does it trip? No. Turn the HP pump on using the control panel on the WW cabinet. Does the breaker trip? No.
turn breaker off. Reconnect wires from contactor to motor. Turn breaker on. Turn HP motor on using the WW control panel. Does it trip? If YES, remover belts and try again. This “should” eliminate anything from the breaker to the motor and push me to investigate a pump issue.
You should also be checking the voltage on each leg at each step to be sure you don’t have a broken wire somewhere.
 
About 15 years ago we had a lose wire on a mark 7 machine with a cat 3535. The issues kept tripping breaker and melted the buss bar in the panel box until it was finally found in a junction box somewhere. After panel replacement electrician wired dryers backwards and they sucked instead of blew for 1 year later.
 
I have to agree with Eris, whoever the electrician you called should be fired or go back to relearn his trade. I’d diagnose the problem just like what Eric has said. If the breaker trips as soon as the blower comes on you've got a dead short somewhere. Also do what Dakota has said and check all the connections going to the blowers.
 
Eric H said:
You’re electrician needs to be fired. This diagnosis should be fairly simple especially if the condition occurs every time. If it was an occasional trip issue it would be more difficult to diagnose. If the electrician can’t perform this simple test he is notqualified and is stealing your $$.
I agree with others get a clamp on amp meter and check each legs amperage. Check voltage for each leg before continuing.
I’d start by switching the breaker off and disconnecting the wires from the motor contactor to the motor. Switch breaker on. Does the breaker trip? No. Push motor contactor in manually. Does it trip? No. Turn the HP pump on using the control panel on the WW cabinet. Does the breaker trip? No.
turn breaker off. Reconnect wires from contactor to motor. Turn breaker on. Turn HP motor on using the WW control panel. Does it trip? If YES, remover belts and try again. This “should” eliminate anything from the breaker to the motor and push me to investigate a pump issue.
You should also be checking the voltage on each leg at each step to be sure you don’t have a broken wire somewhere.
Click to expand...
He is horrible
 
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