How do save the motor winding from the ground fault.

Not something I readily admit to, but I had a similar situation and ended up drilling a hole in the lower end of the motor case (missing all windings and other internal parts) so any fluid getting in the motor would drain out the bottom.

In this installation to prevent the leaking fluid from spraying all over the unit I would add a drain tube.

Another thought is to add an oil slinger on the motor shaft that would send any fluid out the slots in the coupling housing. Plus that would give the operator a chance to see the fluid before it collects in the motor, especially if he has to mop it up more than once.

What size hole would be best? Is there no any safety issue?
Thanks.
 
Depending on the viscosity of the fluid.

Water thin would do OK with a 1/4" / 6mm copper tubing coming out, syrup type may need 3/8" / 10mm

I actually like the idea of putting an air fitting and a small,precise regulator and pressurizing the motor, but not too much to blow out the seals or bearings. 1 to 2 PSI at the most.
 
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Her is a link to help explain it

https://www.hecoinc.com/blog/insulating-electric-motors-vpi-or-varnish

I have had more than a few motors done I have even requested on new motors that were going into a harsh environment. I have takes new motors and sent the out to get VPIed before they were installed
it epoxy seals and stabilizes the windings
not all motor shops can do it I have found those that can't do it will try to talk you out of or tell you that its not worth the extra money. But they are just trying to keep you motor work in their shop
it dons extend the life of you motors considerably
 
Are you sure it is something leaking into the motor, or is it condensation forming inside of the motor when you turn it off? You mention butter, so I assume this is a food production area, probably kept cold. When the motor has been running and warm, then you shut down in a cold moist area, as the motor temperature passes through the dew point, condensation will form inside and eventually, the winding insulation will absorb it.


The solution is to not allow the motor to get that cool, keep it warm at above the dew point of your facility (dew points vary by humidity). Some VFDs offer the ability to trickle low voltage DC into one winding as a motor winding heater. If yours does not offer that, you can use heating bands around the motor and a separate circuit to power it whenever the VFD is not running the motor, or use motors that have winding heaters built into them.
 
Are you sure it is something leaking into the motor, or is it condensation forming inside of the motor when you turn it off? You mention butter, so I assume this is a food production area, probably kept cold. When the motor has been running and warm, then you shut down in a cold moist area, as the motor temperature passes through the dew point, condensation will form inside and eventually, the winding insulation will absorb it.


The solution is to not allow the motor to get that cool, keep it warm at above the dew point of your facility (dew points vary by humidity). Some VFDs offer the ability to trickle low voltage DC into one winding as a motor winding heater. If yours does not offer that, you can use heating bands around the motor and a separate circuit to power it whenever the VFD is not running the motor, or use motors that have winding heaters built into them.

Yes, I am sure butter or water insert the motor inside. Throughs sealing damge and sometime clean the tank by high-pressure water.
 
If you really have a problem with a liquid running down the motor shaft and passing through the motor seal and bearing. Something I saw many years ago when I first started in the trade may help.
The old timers . the old timers press mounted a slinger collar between the motor bearing , seal and the coupler. Just a simple disk that is large enough so any liquid that would travel down the shaft redirected to the outer edge of the motor housing. Any liquid that would migrate down the shaft while the motors is running would be thrown clear of the motor. It can get to be a bit messy around the motor while it’s running.
I have not seen anybody use them recently. I guess that the seals n the older motors weren’t as good as they are today. A good machine shop should be able to fix you up with one for your motor
 
If you really have a problem with a liquid running down the motor shaft and passing through the motor seal and bearing. Something I saw many years ago when I first started in the trade may help.
The old timers . the old timers press mounted a slinger collar between the motor bearing , seal and the coupler. Just a simple disk that is large enough so any liquid that would travel down the shaft redirected to the outer edge of the motor housing. Any liquid that would migrate down the shaft while the motors is running would be thrown clear of the motor. It can get to be a bit messy around the motor while it’s running.
I have not seen anybody use them recently. I guess that the seals n the older motors weren’t as good as they are today. A good machine shop should be able to fix you up with one for your motor
I like it. Similar to a drip “skirt” on HV terminations. In fact they make those in heat shrink material, that might be a good way to implement it if you could find one that would shrink down to the motor shaft size.
Heat_Shrink_Moulded_Shapes_rain_shed.jpg



Alternative #2 might be to have better quality shaft seals installed on your motor. If you are buying cheap motors because they fail so often, you might be throwing good money after bad. I have had great success in extreme conditions using high quality shaft seals like Inpro/Seal. The motor mfrs will often use them on their Severe Duty motors (aka IEEE 841 design spec), but you can have the seals retrofitted to standard motors by a good motor shop.
 
You will have always this problem due to condensation of the motor. So you will need to make the motor vaportight, and or heating inside the motor.

when it is product via the shaft, make a cover close to the coupling , so the product can not touch the shaft.
 
If the belt slip because of the environnement, what about a 90 deg gear box to mount the motor horizontally if the above solution isn't working?

You won't solve ground fault by the VFD, it is a fault to detect the problem before everything smoke.

Have you get you motor inspected to make sure it was grounded because of the product ?
If it isn't condensing because the room get cold as explained, it could be because of voltage spikes. Especially if you have long wires to make it worst. A choke at drive output could help this.
 

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