[TheForge] HP ratings

[theforge@mailman.qth.net]

Commercial motors designed for compressor applications are designed to 
handle the high belt tensions encountered ( as opposed to fan 
application).  Further, motors pull more amperage during startup than 
during normal running.  Since compressors will cycle frequently, purpose 
built motors will account for this in the windings.   I don't know of 
any official definition of "compressor duty" though, and for non 
industrial products think compressors are one of the many places where 
marketeers go crazy on their ratings.   

Dave Brown wrote:

> From discussions past, the details of which are foggy, I understand 
> that the HP ratings of new motors these days is something different 
> than it used to be.  A new 2hp motor isn't the same as an older 2hp 
> motor, right?  So, with our regard to the specifics of how HP ratings 
> are applied/assigned, how much difference is there between, for 
> example, an older (big ol' frame and weight type) 2hp motor and a new 
> 2hp motor?