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Motor overload troubles

Motor overload troubles

Motor overload troubles

(OP)
I am having troubles with three overloads tripping. Two of them are trim saws and the other one is a hydraulic power pack. The have nothing to do with each the only thing they have in common is that they are on the same vertical bus bars. They all trip out at the same time. I moved the tub for the hydraulic power pack and now it is not tripping out but the trim saws continue to trip out even when the are not trimming the wood. Is this a bus bar issue or bad overloads? The overloads are siemens ESP 100. Can anyone help please.

RE: Motor overload troubles

Have you measured the current at which they're tripping?

Give us lots more data.  It could be a wide variety of issues.

Good on ya,

Goober Dave

RE: Motor overload troubles

Measure system voltage at the point where your loads are connected too.
  

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If we learn from our mistakes I'm getting a great education!
 

RE: Motor overload troubles

(OP)
I had my clamp on amp meter on them and the current dropped right off and then came back and then went low and did this for about five seconds and then they both tripped. I put my meter on a another phase to see if that one was drawing high current but it didn't. I thought maybe I had a phase loss driving the other two up causing the overloads to trip. I think i will move one tub at a time to a new set of vertical bus bars and go from there.

Thanks

RE: Motor overload troubles

While you have the starter out on the bench have a good look over it: inspect the main disconnects, the contactor pole faces, and all connections. Your sense of smell is often a good guide when screwy stuff starts happening.
  

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If we learn from our mistakes I'm getting a great education!
 

RE: Motor overload troubles

(OP)
I found the problem. The main bus bar on the MCC was loose and started to heat up adn melt. It was loose so I was having voltage drop problems

RE: Motor overload troubles

Beat me to it, good job. The big clue was when you said you moved the bucket and the problem went away.

You should now do a very thorough inspection of all of the stab assemblies in each bucket that was stabbed onto that offending bus bar (if it was the vertical). If it was the main horizontal bus, inspect every stab assembly fed from that main bus and any bolt-on connections for signs of thermal stress. If the stabs over heat from LV like that, the springs can lose their tension and the failures start happening more rapidly.

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RE: Motor overload troubles

Good that you found it... could've been worse I imagine.

Thanks for sharing your results.

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(2B)+(2B)'  ?

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