# Operating a 60 hz Induction motor at 50 hz

If i had an Induction motor that runs on 460 volts ,35 amps , develops a power of 35 hp at a speed of ~1800 RPM ( data acquired from a nameplate )

How is it possible to calculate the same parameters if i wanted to run this motor at 50 hz instead ? what equations should i use ? , all i know is that power would decrease as well as RPM (obviously).

• lower f means higher current and less margin to flux saturation on core resulting excess heat.. – Tony Stewart Sunnyskyguy EE75 Mar 5 '17 at 0:50
• You can do it in most cases, but the power output will drop to about 0.75-0.85 of the plate rating at 60 Hz. This might help you: usmotors.com/TechDocs/ProFacts/50Hz-Operation-60Hz.aspx – Jack Creasey Mar 5 '17 at 0:52
• For sure you can run it at 50 Hz at reduced voltage. You would use 460V * 50 Hz / 60 Hz = 383 V. Power and RPM's would be similarly reduced. Of course you might not have that Voltage handy unless you are using some kind of VFD. I have seen some motors rated for both 60 Hz and 50 Hz. Are you sure the nameplate makes no mention of 50 Hz ratings? Is it a totally enclosed, fan cooled (TEFC) motor? – mkeith Mar 5 '17 at 1:50
• @mkeith: Actual maximum voltage for that motor is more likely to be 480 Vac. That also implies that it is a 3-phase motor. Applying the correction factor of 50/60 leads to an input voltage of 400 Vac. This is mighty close to the 415 Vac available from many European countries. – Dwayne Reid Mar 5 '17 at 4:28
• @DwayneReid very good point. It's a happy accident; we have a heritage of 240 doubled to 480 delta/wye for industrial, while their residential mains power is aimed at 230/leg which works out to 400 wye. Sounds like the reverse would work too; a Euro 400V-50 motor would run ok at 480-60, albeit at higher speed. – Harper Mar 5 '17 at 5:53