UL REPAIR SHOPS

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hawkeye23

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stanton
Do motor rewinds have to be made by a listed motor shop ? I have read that in a classified area rewinds need to be done by ul shops. If this is true how are hid lighting repairs handled ? Are they abled to be repaired by the plant maintenance people or just replaced with new? Where does one get the correct T - Rating for the fixtures ? Seems like a touchy area for repairs.
Thanks to anyone who might be able to help.
 
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rbalex

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Location
Mission Viejo, CA
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Professional Electrical Engineer
Only explosionproof motors require repair at a UL shop. The problem isn't the rewind but the care required diassembling/reassembling enclosures because of the machined surfaces and bearing alignments.

Most, but not all, explosionproof luminaires use threaded interfaces. If relamping/rebalasting is the only issue, it can be done in the field. Damage may need replacement - contact the factory, especially if there is damage to machined surfaces (even what appears to be "minor" scratches) or threads. Actual "cracks" or deformation will definitely require replacement. The "T-Code" is part of the required information on the labels in classified locations. See Sections 500.8 in general and 500.8(B)(1), 500.8(C) and 501.130(A)[especially 501.130(A)(1)] for more specifics.
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
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EE (Field - as little design as possible)
Only explosionproof motors require repair at a UL shop. ...
Bob -
I've heard that plenty of times. But other than, "The AHJ said so" - I've not seen a regulation that mandates a UL listed motor shop do repairs on expf motors.

Can you point me to the applicable regulation?

ice
 

rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Bob -
I've heard that plenty of times. But other than, "The AHJ said so" - I've not seen a regulation that mandates a UL listed motor shop do repairs on expf motors.

Can you point me to the applicable regulation?

ice
Basically, only a UL motor repair shop can "recertify" a repaired UL explosionproof motor. There are about 400 such shops.

As I mentioned before, rewinding isn't the real issue; it's the demonstrating the skill necessary to disassemble/reassemble the enclosure that is necessary. The smallest scratch on a machined surface can destroy an enclosure.

I guess theoretically UL doesn't have to be the NRTL involved but, to my knowledge, no other NRTL certifies explosionproof motor repairs.
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
Basically, only a UL motor repair shop can "recertify" a repaired UL explosionproof motor. ...
So Motors for haz location sare White book PTDR, which says for rebuilt motors use PTKQ. And the shop has to be able to apply a Listing Mark which means they have to be a "UL" shop. And the rebuild is investigated per UL674. This applies to only motors built to UL674.

Do I have that right so far?

... As I mentioned before, rewinding isn't the real issue; it's the demonstrating the skill necessary to disassemble/reassemble the enclosure that is necessary. The smallest scratch on a machined surface can destroy an enclosure. ...
Maybe. I looked at the white book PZRA, Motors for Zone classified Haz locations. There is no similar requirement for rebuilt motors. I looked at IFUX, Luminaires for use in Haz location. There is no similar requirement.

Apparently one can do field rebuilds of zone classified motors or Haz location luminaires and be just fine. If it is a case of disassembly/assembly skills wouldn't one think that would apply to these as well?

Without additional information, this appears foolish or political.

ice
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
So Motors for haz location sare White book PTDR, which says for rebuilt motors use PTKQ. And the shop has to be able to apply a Listing Mark which means they have to be a "UL" shop. And the rebuild is investigated per UL674. This applies to only motors built to UL674.

Do I have that right so far?


Maybe. I looked at the white book PZRA, Motors for Zone classified Haz locations. There is no similar requirement for rebuilt motors. I looked at IFUX, Luminaires for use in Haz location. There is no similar requirement.

Apparently one can do field rebuilds of zone classified motors or Haz location luminaires and be just fine. If it is a case of disassembly/assembly skills wouldn't one think that would apply to these as well?

Without additional information, this appears foolish or political.

ice
It would not surprise me at all that UL would list them this way to encourage shops to become UL listed repair shops. It may not be to your liking, but some times things just are the way they are.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
So Motors for haz location sare White book PTDR, which says for rebuilt motors use PTKQ. And the shop has to be able to apply a Listing Mark which means they have to be a "UL" shop. And the rebuild is investigated per UL674. This applies to only motors built to UL674.

Do I have that right so far?
So far

Maybe. I looked at the white book PZRA, Motors for Zone classified Haz locations. There is no similar requirement for rebuilt motors. I looked at IFUX, Luminaires for use in Haz location. There is no similar requirement.

Apparently one can do field rebuilds of zone classified motors or Haz location luminaires and be just fine. If it is a case of disassembly/assembly skills wouldn't one think that would apply to these as well?

Without additional information, this appears foolish or political.

ice
Actually the Category Code for Zone marked motors is "PRZA". Now if you can just find a PRZA manufacturer. (Click "View Listings" in the upper left hand corner)

Also note a few other things. You would either need to be using a "Zone" (Art 505) rather than a "Class" (Arts 501 or 502) classification system OR a valid Zone to Class equipment substitution per 501.5 or 502.6 - good luck with that.

Dispite any claims that Division 1 includes both Zone 0 and Zone 1, any one familiar with the IEC version knows Zone 1 is actually a glorified Division 2. US domestic Zones were "force fit" into the Divisions - which is why you can't find US domestic Zone [AEx - 505.9(C)] marked motors (there's no design for them)
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
Only explosionproof motors require repair at a UL shop. The problem isn't the rewind but the care required diassembling/reassembling enclosures because of the machined surfaces and bearing alignments.

... If relamping/rebalasting is the only issue, it can be done in the field. Damage may need replacement - contact the factory, especially if there is damage to machined surfaces (even what appears to be "minor" scratches) or threads. Actual "cracks" or deformation will definitely require replacement. ....
...Actually the Category Code for Zone marked motors is "PRZA".

...Now if you can just find a ... PRZA manufacturer...

Also note a few other things. ...
Thanks for fixing my spelling. And this is all very interesting.

However, my point is still valid. One can do any field maintenance one wants on classified luminaires. If this "care required diassembling/reassembling enclosures because of the machined surfaces and bearing alignments" is the reason for requiring maintenance by a UL motor shop, then why doesn't apply to the classified luminaires?

I also question the concept of "bearing alignment" in a motor. For all I have ever done - the bearing gets heated and slid on the shaft, bearing cools and grabs the shaft. Not sure where this bearing alignment comes in.

Although you didn't mention it, I believe a non-ul motor shop is just as likely to put in the correct bearings as a UL shop. They are both going to pop out a grease shield if they have the right bearing other than that. Neither will special order a bearing.

I still contend it is fool ...... ah well no use repeating.

ice
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
So Motors for haz locations are White book PTDR, ...

... Without additional information, this appears foolish or political.
It would not surprise me at all that UL would list them this way to encourage shops to become UL listed repair shops. It may not be to your liking, but some times things just are the way they are.
Your absolutely correct. Except it really has nothing to do with my liking or not liking. I am mostly concerned that a knowledgable person contends that it actually matters.

Bob did a great job in getting me to read the White book (my 2008 version) and look up UL 674 and down loaded a new copy of the White Book (2011). I now know the regulatory issues. I didn't before.

I have not personaly rebuilt an exp-proof motor in over 40 years - well, except for the one on the fuel tank out at my property. (Amazingly the new bearings lined up just fine. And I even could buy a new centrifugal switch for it.) But I have not done one for hire and I can't think of a reason where I would - because, as you say - "things just are the way they are" :happysad:

ice
 
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