Old Motor Electrical Connections Encased in Oil ?

33oneill · Jul 26, 2016

I'm not sure where to post this electrical motor question but I will try here first.

I'm putting a new / old electric motor on my lathe. Tonight I was going to wire it up to a VFD but when I opened the electrical connection junction box on the back of the motor a fair amount of oil came out of the junction box.. The connection box cover had a cork gasket that makes me think that the oil was meant to be in there. I can also see the leads coming out of the motor and into the junction box but I don't see any obvious signs of oil coming from the interior itself.

I am hoping that one of you could tell me if that is normal or not and if it is normal should I replace the oil or fill it back up?

Winterfalke · Jul 26, 2016

99.9 percent sure the oil is not supposed to be there. The gasket is to make the junction box weather resistant. I suppose a type of oil could be used to make a connection more waterproof/thermally stable, but that is not a suitable junction box for a submerged connection. Looks like just a normal motor.

blcksmth · Jul 26, 2016

Submersible sump pump motors are filled with oil.

Bob
WB8NQW

Winterfalke · Jul 26, 2016

True, usually for heat dissipation and to eliminate any air gaps that might fill up with water at pressure. But they are usually fully encased in a metal can with a seal and cap at one end. I have never seen one with the j-box on the side.

Fun fact: if you give your rebuild tech your pressure reg set to plumb into one of those submersible motors to pop the seal, and he forgets to dial it back to 2 or 3 psi, you can empty the entire can in under one second. And your tech will go home completely covered in atomized transformer oil.

rons · Jul 27, 2016

Winterfalke said:
99.9 percent sure the oil is not supposed to be there. The gasket is to make the junction box weather resistant. I suppose a type of oil could be used to make a connection more waterproof/thermally stable, but that is not a suitable junction box for a submerged connection. Looks like just a normal motor.

I would hike that up to 100*.

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Old Motor Electrical Connections Encased in Oil ?

33oneill

Plastic

Winterfalke

Stainless

blcksmth

Cast Iron

Winterfalke

Stainless

rons

Diamond

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