Hi,  Peter Neilson wrote in 140421 MMDigest:

> Does anyone know if there is a problem in running 110-volt motor
> equipment at 120 volts?  Yes, it's only a 9% overvoltage, but that
> could result (if my estimate is correct) into as much as an 18%
> increase in power consumption, with possible consequent premature
> failure.

Not a problem.  Generally speaking, motors are rated for operating
voltage, not nominal line voltage.  For instance, you won't find a
"120 volt" motor but you'll find 115 volt ones.  I'm referring to
separate motors large than 1/5 HP, not those built into appliances.
The motor only consumes the power it's required to deliver; at the
slightly higher voltage, it'll draw more on startup (and deliver
more torque then), but the run current should be a little lower.
It'll be fine.

The numbers Robbie posted look rational for about 1 horsepower of
not-so-efficient motors, and the starting current is in line with
standard induction motors (peaking at about 2.5 times the run current).

Another thing is temperature rise.  A modern motor might have a
temperature rise rating of 60 deg. C.  That's the maximum temperature
over ambient, which is assumed to be 40 deg. C.  Leaving a lot out
here, the motor at full load is too hot if it's over 100 deg. C. (or
212 deg. F.).  Most people would consider a [modern] motor at 150
degrees F. to be _way_ too hot, but it's really okay.  I can't speak
to antique motors with original windings.  Either way, hot to the
touch is okay, "burn-your-finger" is not!  :)

Also, any discussion of motor currents should include the nameplate
information: voltage, current, HP, speed, etc.

z!
Carl Zwanzig