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h2045
05-19-2005, 01:43 PM
Years ago I recall there being a reason there are never any, fan,pump, or compressor motors at 3600 RPM. Something about harmonics or some other jazz like that. Does anyone else know of this and be kind enough to repeat it for me.

Thanks
John
Wild Leg
05-19-2005, 01:49 PM
Quite a few compressor motors are 2 pole, therefore 3600 nominal.
A fan would be awfully loud.
Pump motors?
I don't know, probably more likely to cavitate.
tpa-fl
05-19-2005, 02:04 PM
I don't see why anything couldn't run at 3600 RPM... many generators run at this exact RPM with no ill effects.
freonrick
05-19-2005, 03:59 PM
i have worked on lots of pumps that is 3600 rpm.
snipe70e
05-19-2005, 06:54 PM
Most motors are some form of inductin motor. an induction motor has "slip". That is it turns slightly slower than Synchronous speed. that is why the speed of 3550 rpm is common.

A Synchronous motor is a special type of motor. An for a high hp motor the most common is induction start synchronous run and they require an source of external DC excitation.
ozone drone
05-20-2005, 07:20 AM
I have 2 Munters air handlers that have 1.5 hp 3600 rpm supply fans at my bldg.
hvacpope
05-20-2005, 06:34 PM
[QUOTE]Originally posted by tpa-fl
[B]I don't see why anything couldn't run at 3600 RPM... many generators run at this exact RPM with no ill effects.

Its the evil flux effect, I blame it on the dark side.
ga1279
05-20-2005, 06:48 PM
In general when working around centrifugals they employ a 2pole motor or 3450 rpm when you allow for slip. Some compressors are geared up (higher impeller speed) but all manufactures warn not to use pumps of the same speed as it sets up a ressonant harmonic vibration and sounds through out the piping. For this reason chill water and condenser water pumps are limited to 1750 rpm.
freonrick
05-20-2005, 08:59 PM
there is chilled and condenser water pumps in industrial applications that is rated at 3600 rpm.
snipe70e
05-20-2005, 10:37 PM
Originally posted by tpa-fl
I don't see why anything couldn't run at 3600 RPM... many generators run at this exact RPM with no ill effects.

Most generators are synchronous and do run at 3600 or 1800 RPM
snipe70e
05-20-2005, 10:40 PM
Originally posted by freonrick
there is chilled and condenser water pumps in industrial applications that is rated at 3600 rpm.

I think you will find that they have either soft start or are 3450 to 3550 RPM