NEMA Protection

[magneticted]

Hi guys, for IEC motors when considering degrees of protection, it quite clearly defined under IEC60034-5, Degree of protection using IP codes. Is there anything in NEMA standards which is equilavent to. We have come across a list of NEMA enclosure types from 1 to 12, for example NEMA 4 or NEMA 4X,which correspond to IEC 60529 IP codes in this case IP56. and I think the definitins are from NEMA 250-1997.But these NEMA types do the relate to motors or other equipment like terminal boxes / conduit boxes. Only when looking at NEMA manufactured motors there appears to be no reference to NEMA type 4 etc. So is there a IP code described in NEMA standards

 

[Skogsgurra]

There is no direct correspondance that I know about. I think that acronyms like TEFC (Totally Enclosed Forced Ventilation, would probably be an IP54) and similar are being used. I have once seen a list where IP and NEMA was listed but I have to find that again before I can say anything more.

The NEMA 4 and similar is more for cabinets and enclosures, I think.

Gunnar Englund

http://www.gke.org

 

[jraef]

Correct, in NEMA motor designs there is no protection degree system as finite as the IEC system. There are NEMA "standards" that delineate protection designs, but NEMA is not a testing authority, so adherence is voluntary. That said, the competitive marketplace keeps manufacturers in line. If you buy a motor that is rated for "severe duty" and it fails in short order due to water ingress, you, and everyone you know, are going to make sure to never buy that brand again.

Here is a brief synopsis of the NEMA enclosure classifications for motors. Note that NEMA only covers up to 250HP, so there are additional enclosure designations for larger frames, such as WPI and WPII (Weather Proof type I and II).
Engineering Toolbox Link Many individual NEMA mfrs have sub-categories of these classifications as well. Visit their websites and look for their technical data to see what they offer and what it means; i.e. Reliance, US Motors, Baldor, Leeson etc.

If you want to see the full text of the NEMA standards, you need to purchase them, use this link. NEMA link

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