Melted motor terminal post?

-Matt · Mar 17, 2019

Customer has this 110KW (converted to 55KW) motor powered via a generator.

They had a problem with the generator cutting out on startup showing overload fault.

Having investigated this issue, along with the motor overload having been bypassed!! (will be rectifying this!)

when I took the cover off the motor I noticed the nylock nut had melted its plastic with signs of overheating.

whilst removing the link bar to test the coils, I found the whole terminal post had melted out of the insulating section. and pretty corroded terminals.

My assessment is a poor connection on the terminal posts .

The coils seem ok.

Im trying to get a motor expert to come out and give his opinion and repair option. however having trouble getting someone out quickly, and customer needs this running ASAP.

Can anyone think of a temporary or permanent, safe fix?
I guess it really needs new terminal block and posts?

What do you guys think?

[ElectriciansForums.net] Melted motor terminal post?

westward10 · Mar 17, 2019

Looks like they have all been overheating.

telectrix · Mar 17, 2019

gorilla ~~snot~~ glue.

Wilko · Mar 17, 2019

Hmm - someone has troubled themselves to bypass the thermal overload and now terminal plate has melted. Is the motor running overloaded or am I reading too much into this?

westward10 · Mar 17, 2019

You may expect one post to fail for some reason but to me they are all showing signs of overheating. Get a specialist to look at it and don't attempt an ad hoc repair.

snowhead · Mar 17, 2019

Ulimately a new block.
They're fairly standard, has the customer got an old / spare motor around?

But, you'll need a new crimp on the ends coming from the windings (or clean the existing up).

As W10 above, they all look to have damage, so clean up all the ring crimps from the windings and nuts /screws.
And the supply cables.

Then new ring crimp onto the supply cable, use a new /clean screw / nuts and washers to the damaged one.
Heat shrink over the joint if you've got any big enough (put on firts of course) tie wrap the joint away from the block so it doesn't bounce around.

Silly Sausage · Mar 17, 2019

westward10 said:
Looks like they have all been overheating.

Have you noticed the fire extinguisher sitting near by?

snowhead · Mar 17, 2019

Wilko said:
Hmm - someone has troubled themselves to bypass the thermal overload and now terminal plate has melted. Is the motor running overloaded or am I reading too much into this?

It's O.K they've left a Fire exstinguisher by the Motor.

Silly Sausage · Mar 17, 2019

snowhead said:
It's O.K they've left a Fire exstinguisher by the Motor.

At least two of us have got good observational skills around here

westward10 · Mar 17, 2019

I would want to know why they have ended up like that, yes a new block can be fitted but long term do you end up in the same situation or worse.

westward10 · Mar 17, 2019

How has it been converted to 55kw.

-Matt · Mar 17, 2019

Wilko said:
Hmm - someone has troubled themselves to bypass the thermal overload and now terminal plate has melted. Is the motor running overloaded or am I reading too much into this?

I suspect it was a temporary bodge that was never rectified, its been like that any least a year.

I actually measured the running currents of this motor a few weeks ago (with aim of getting onto grid supply) and it varied from around 50-100A, which FLC of 97A for a 55KW motor seemed ok.

westward10 said:
You may expect one post to fail for some reason but to me they are all showing signs of overheating. Get a specialist to look at it and don't attempt an ad hoc repair.

Hopefully a specialist will get out tomorrow.

westward10 said:
How has it been converted to 55kw.

That is a question I asked, but they don't know was the answer...

snowhead · Mar 17, 2019

-Matt said:
westward10 said:

How has it been converted to 55kw.

Click to expand...

That is a question I asked, but they don't know was the answer...

There isn't a Variable speed drive somewhere is there?

ipf · Mar 17, 2019

If they were solid connections, I find it difficult to understand why a terminal would burn out like that before a winding going down.
Looks like a complete rewind and terminal block, who knows the internal damage done. How do the windings read?