NEMA WP1 definition 1

[rotormotor]

Hi

Can someone please give me a detailed definition of the NEMA motor enclosure rating WP1. I understand this is "Weather Protected 1" and I also know that there is a higher rating called WP2.

The exact wording as per the NEMA standards would be great or just an accurate description would be most appreciated. Is there a cross reference from the NEMA enclosure rating to an equivalent IP rating?

Thanks
Rotormotor

 

[dpc]

Is there any forum that you didn't post this question on?

WPI: "A weather protected type I machine is an open machine with its ventilating passages so constructed as to minimize the entrance of snow, rain, and air-borne particles to the electric parts and having its ventilating openings so constructed as to prevent the passage of a cylindrical rod 3/4" in diameter."

WPII is a much better enclosure. WPI is the bare minimum for outdoor service.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[rotormotor]

Hi dpc

Only one other forum and I didn't get an answer so I thought I'd try here.

Thanks for your definition. I have an application where we have a WP1 rated motor outdoors, vertically mounted, unprotected in the middle of a paddock only 5km from the sea. This motor has failed four times and seems be getting contamination inside. The VSD that drives it is being blamed for the failures. The motor rewinders are balming it on dv/dt but this isn't the case.

I'm wondering if the WP1 rating isn't high enough. In this part of the world we don't typically use NEMA standards so I really didn't know how WP1 was defined.

Do you have any idea of what the equivalent IP rating is?

Thanks
Rotormotor

 

[dpc]

Seems possible. WP I is just barely more than open-drip-proof with a little weathershielding tacked on. Dirty, dusty environments are not a good application. WP II would generally be much better, and usually has filters, IIRC.

I'm not sure about the cross-reference with IEC. I'm sure US Motors or Toshiba US could tell you.

What's the failure mode? Stator winding faults?

Check this out:

http://web.tampabay.rr.com/oldman/nema_motor_enclosuretypes.htm

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg