50hz-60hz

[jamcool]

Guys.
what are the pros or cons(if any) if say a 50 HZ (cycle) compressor is run on a 60 HZ (cycle) system and vice versa? with the comp. being rated for only one cycle and not both?:)

[Peter_1]

It will give +/- 20 % cooling capacity, it will pull more current, it will wear faster, it will make more noise.

I think almost any 50 HZ compressor can run on 50 Hz. This will give no serious problems als long as you stay under max allowable current.

[frank]

We fitted some 60hz fans some years ago (240V) and they burnt out in a very short time.

We also had some York condensing units imported to the UK, via France, where the wiring was "upgraded" to comply with CE certification. We had enormous problems with these units as the cam timers continually burnt out as they were 60 hz. Even the replacements supplied by York were 60 hz so the problems just went on and on.

It appears that 60 hz equipment causes the motor to run faster creating more heat which eventualy destroys the motor.

If you apply the formula for motor speed (RPM = 60*hz/pole pairs - friction factor) then for a 50 hz supply we get 60 x 50 /2 (for a 4 pole motor) - 4% = 1440 RPM

If you apply the same motor to a 60hz supply you get 1728RPM - an increase of 20.16%.

Hope this helps.

[Peter_1]

With compressors, you have an increased massflow, so the compressor will cool enough.

[nico sonico]

hi!
i have also tha same problem, we have a water chiller design 400v, 50hz: but our supply here is 440v, 60hz so we have to change the primary transformer and the pump motor that will fit in 440v 60hz, is it will couse problem with the whole unit, how thus affect the cooling system of the chiller,,

thanks
nico sonico

[Robearbam]

Hey guys, here in the US the 50 hz thing is a problem with motors. We had a machine quite a few years back that was from Italy I believe. Most of the motors we had to have rewound. The only 50 hz motors that were successful thoughout the machine's existence were the ones that did not run constantly....they were pulsed for short periods of time. It was a very long ordeal with the motorshop and a lot of heartache. Interesting what Peter had mentioned about the cooling effect. I have done that with large transformers....keep them cool and the capacity can be increased.

[frank]

keep them cool and the capacity can be increased.

A little bit like cooling a CPU then and increasing the computing speed? :)

[US Iceman]

...keep them cool and the capacity can be increased

The same thing happens to fan motors in cold storage. The motor amps increase due to the higher air density, so in effect you are getting higher output from the motors. The cold air provides sufficient cooling from cooking the motors.