Some of our explosion proof motor in our plant were completely submerged in water for about 15 to 20 hours. The 480 is locked out and they were never powered up while submerged. Should these motors be pulled, disassembled and baked/cleaned before putting back into service?
Submerged Motors
- Thread starter session88
- Start date
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hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Most EP motors a gasketed and pretty much sealed but this doesnt mean they are always water proof, removing one of the bell ends will show if any water has entered the motor, and just heating the motor up will not allow the water to excape without opening up one of the ends. after opening up an end just use a heat gun to allow it to blow through the motor but just don't get it too hot.
SG-1
Senior Member
- Location
- Ware Shoals, South Carolina
You may want to consider a megger test for the windings.
- Occupation
- Licensed Electrician
I agree with Hurk.
We service motors at our shop. If we get one that has been flooded, but has not tried to run wet we open it up, flush it out, and warm it in an oven to make sure it is dry.
Once you have gone that far it is no big deal to change the bearings as well.
We service motors at our shop. If we get one that has been flooded, but has not tried to run wet we open it up, flush it out, and warm it in an oven to make sure it is dry.
Once you have gone that far it is no big deal to change the bearings as well.
ptonsparky
Tom
- Occupation
- EC - retired
Our closest motor rewind shop does not work on explosion proof motors because they are not certified for it. Are you?
kwired
Electron manager
- Location
- NE Nebraska
At what point does one draw the line between needing to be certified or not? Can you connect the motor to the branch circuit if you are not certified? Rewinding or other repairs involving the integrity of the shell of the motor are understandable. Removing the end housings I guess could be damaging to the seal of the motor from the exterior environment.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
The line is drawn by the fact that explosionproof motors are listed and general purpose motors are not.
kwired
Electron manager
- Location
- NE Nebraska
Many things are listed, are we not allowed to service listed items unless certified by some third party?
I can understand a motor shop not wanting to assume liability if they rewind an explosion proof motor if they are not properly trained to do so and retain the explosion proof listing. To change a bearing is a little different. There is a possibility that you must use a specific bearing to maintain listing. I see that as a little like an explosion proof luminiare designed to accept a 100 watt lamp and having someone put in a 150 watt lamp. Directions need to be followed.
- Occupation
- Licensed Electrician
No we are not certified for it. The occasions we have to work on explosion proof motors they are not used in a classified areas.
ptonsparky
Tom
- Occupation
- EC - retired
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Indeed, in its simplest form, that's what 110.3(B) says. And part of those directions for explosionproof motors is that repairs (a logical extension of "...used in accordance with...") are to be done by a qualified shop.
UL maintains a unique category code (PTKQ) for shops certified for "Motors and Generators, Rebuilt for Use in Hazardous Locations" There are a bit more than 400 such shops. A few of my larger or remote refinery clients maintain UL qualified explosionproof motor and generator shops onsite.
- Occupation
- Licensed Electrician
Do you deliver overnight?
Here's a recent example- changed the bearings and pump seal on explosion proof motor owned by a micro-brewery. Owner said he bought it on e-bay. It needed to be a totally enclosed motor, but did not need to be explosion proof.
If an explosion proof motor comes into the shop that is used in an area where it is required to be explosion proof we order a new one.
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