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Weland
Guest
Thu Dec 08, 2011 1:03 pm
On 2011-12-07, Michael A. Terrell <mike.terrell_at_earthlink.net> wrote:
Quote:
Weland wrote:
On 2011-12-06, Phil Allison <phil_a_at_tpg.com.au> wrote:
"Phil Allison"
The motors will run 20% faster at 60 Hz - and maybe a tad warmer.
** A 60Hz design motor will run slower and warmer at 50Hz.
Why warmer?
Magnetic saturation of the iron in the rotor and stator. It's the
same as transformer saturation at a lower than design frequency, if you
don't reduce the input voltage.
Ah, indeed. I forgot about this one, all I was thinking was higher frequency
should result in the motor running warmer due to increasing iron losses.
Thanks!
--
weland_at_sdf.org
SDF Public Access UNIX System -
http://sdf.org
% grep me no patterns and I'll tell you no lines
Michael A. Terrell
Guest
Thu Dec 08, 2011 2:33 pm
Weland wrote:
Quote:
On 2011-12-07, Michael A. Terrell <mike.terrell_at_earthlink.net> wrote:
Weland wrote:
On 2011-12-06, Phil Allison <phil_a_at_tpg.com.au> wrote:
"Phil Allison"
The motors will run 20% faster at 60 Hz - and maybe a tad warmer.
** A 60Hz design motor will run slower and warmer at 50Hz.
Why warmer?
Magnetic saturation of the iron in the rotor and stator. It's the
same as transformer saturation at a lower than design frequency, if you
don't reduce the input voltage.
Ah, indeed. I forgot about this one, all I was thinking was higher frequency
should result in the motor running warmer due to increasing iron losses.
Thanks!
You're welcome. :)
--
You can't have a sense of humor, if you have no sense.
Cydrome Leader
Guest
Sat Dec 10, 2011 12:33 am
klem kedidelhopper <captainvideo462009_at_gmail.com> wrote:
Quote:
On Dec 7, 2:23?pm, "Phil Allison" <phi...@tpg.com.au> wrote:
"Cydrome Leader"
Phil Allison
** Synchronous motors will normally be OK at either 50Hz or 60 Hz.
This includes AC fans, turntable motors and workshop motors on bench
drills
etc.
Fans and drills don't use synchronous motors.
** ?OK - ? so they use ?" induction " motors, which spin at a speed
determined by the AC supply frequency but are not synchronised with it.
.... ?Phil
Years ago when I worked on military aircraft electronics we would
sometimes connect the lab clock up to the 115V 400 HZ supply. Who says
time doesn't fly on a Friday afternoon....Lenny
haha.
spamtrap1888
Guest
Sat Dec 10, 2011 1:03 am
On Dec 6, 1:21 pm, "Phil Allison" <phi...@tpg.com.au> wrote:
Quote:
"spamtrap1888"
I'm too tired to reason this out; does anybody know: Can a motor
designed to run off 50 Hz successfully run off 60Hz? I dimly recall
that motors designed for one frequency will operate safely on the
other, but which way can you go?
** Synchronous motors will normally be OK at either 50Hz or 60 Hz.
This includes AC fans, turntable motors and workshop motors on bench drills
etc.
Thing is, 50 Hz equates to 230 volts and 60 Hz equates to 120 volts.
The motors will run 20% faster at 60 Hz - and maybe a tad warmer.
Thanks, Phil and everyone. I was concerned, because while I can get a
2:1 transformer to operate a constant-speed motorized appliance, I
can't easily supply power at a different frequency.
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