On Fri, 18 Mar 2005 00:03:52 -0000,
(Robert Bonomi) wrote:

In article ,
LRod wrote:

I don't remember that being claimed, but I can dispense with it
quickly (I thought I already had in my original response). From the
standpoint of the motor windings, it's always running on 120V. Either
the windings are wired in parallel (120V supply) or the windings are
wired in series (240V). Since the motor windings are always seeing
120V it can't possibly have any different life expectancy based on the
input voltage.

Well, things aren't quite that simple. grin

"All else being equal" -- things like distance from the main breaker
panel, gauge of the distribution wire, etc. -- and which I must note
are usually _not_ equal ;

Points I have often made about 120V vs 240V, some in this thread.

The 240v powered motor tends not to 'bog down' as much / as fast as the
120V powered one. This is attributable to the lower 'line losses' upstream
of the motor, resulting in what is effectively a "stiffer" power supply.

"Stiff" being exactly the term I used in this thread when describing
the supply issues.

"Amps drawn" goes up as the load goes up, with the supply voltage remaining
constant.

*IF* the supply voltage does _not_ remain constant, but 'sags', the amps
drawn goes up even *more*, to compensate for the 'sag'.

Which is not stiff...

A result of 'all of the above", plus some other things: voltage sag is
more pronounced and longer duration at 120V than 240V.

Such "parasitic' losses in the motor go up as the *square* of the current.

Yes, I referred to that earlier in this thread. I described it as
voltage drop is four times higher at 120V vs 240V.

This _can_ have an adverse affect on motor longevity.

I didn't connect those dots, but it's also not necessarily a realistic
expectation, either. I can't imagine trying to quantify the
difference.

--
LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

http://www.woodbutcher.net