To good to be true

[wildbill hickup]

LIsted on tag. 3 hp , 320volts, 212 amps. Now if I'm correct 1 hp = 720 watts. Well my calculator says that 320 X 212 = 67840.

This is supposed to be a DC motor it doesn't appear to be that big, 67KW at 4000 RPM. That would mean 8+KW at 500RPM. Got really excited until I started to consider the numbers. Considering the size I would say the hp figure is more like it 1hp 720 watts, 3 X 720 = 2160.


Check out listing at "http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=3855596229&ssPageName=STRK:MEWA:IT">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=3855596229&ssPageName=STRK:MEWA:



IT then someone, anyone, tell me what I'm doing wrong please. Did I just pass up the buy of a lifetime?


Totally confused

Wildbill

[wildbill hickup]

Well now I'm more than totally confused. Where did all that come fron and how did it wind up under hydro it's supposed to be under homebrewed. Time to go back to bed.

[RatOmeter]

Here's the link, fixed up:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=3855596229&ssPageName=STRK:MEWA:
%20IT

Well, 1 HP = 746 Watts, so this motor was rated to provide a max of about 2200 Watts output.  That rating is derived from the formula HP = (Torque * RPM) / 5252 so at some sweet-spot along the whole range of speeds this motor can run, the HP peaks out at 3.

The 320 Volt max rating should probably be view seperately from current.  It is probably more a reflection of the insulation class of the windings.  The 212 A current rating is probably a max rating the windings can take (likely to be briefly) before melting.

I'd say that motor would have been a good choice for a gen, though it'd prolly need gearing up for wind apps.  However, you couldn't expect to get more than about 2kW from it (prolly a lot less).

[Chagrin]

Note that it's a BRUSHLESS DC motor.

I could easily be wrong but I don't think it's possible to use these as generators without serious modification.