50 Hertz vs 60 Hertz

[mgtack]

I was recently asked to hook up a machine that has 50 hertz listed on the name plate. I have seen name plates that state between 50-60 hertz operation. Could this machine be damaged at 60 hertz rather than 50 hertz?

 

[jaggedben]

It probably depends on what kind of a machine it is.

 

[templdl]

There is a greater possibility to run 50hz motors on 60hz but they will run faster. A 4p 50hz motor with a synchronous speed of 1500rpm will run at synchronous 1800rpm at 60hz for example. But the best thing for you to do is to consult with the machine manufacturer.
Please note that it must not be assumed that a 60hz motor can be run at 50hz because the motor will most likely run very hot.

 

[Besoeker]

I was recently asked to hook up a machine that has 50 hertz listed on the name plate. I have seen name plates that state between 50-60 hertz operation. Could this machine be damaged at 60 hertz rather than 50 hertz?

To add to what the others have said, if it is rated for 50Hz, you might also want to check the rated voltage. Where 50Hz in common (Europe), the supply voltage is usually 400V three phase and 230V single phase.

 

[Jraef]

I was recently asked to hook up a machine that has 50 hertz listed on the name plate. I have seen name plates that state between 50-60 hertz operation. Could this machine be damaged at 60 hertz rather than 50 hertz?

Flow chart:
Motors: No? Probably fine. Resistive loads and things with power supplies generally don't care about incoming frequency.
Yes? What kind? DC? Probably fine, but check voltage. DC motors and an AC feed means a rectifier, 99% of them are frequency insensitive.

AC? What voltage?
400V nominal (includes 380, 400 and 415V), go to Load?
230V? Possibly a deal breaker, see V/Hz ratio.

Load? If it's a centrifugal pump, probably a deal breaker. Centrifugal pumps will increase the HP requirement at the cube of the speed increase. So 50-60Hz is 120% speed, the pump will require 1.2x1.2x1.2 = 173% of the original HP. The motor HP will increase 20%, but unless that motor started out being grossly overnsized, it won't work.

V/Hz ratio. Motor torque is based on a designed ratio of voltage and frequency. If you alter that, you change torque and thereby HP. If you maintain the same ratio (within tolerance), no problem other than the load type above, but if the motor is 230V 50Hz and you give it 230V 60Hz, you are lowering the ratio and the motor will actually produce less torque. If the motor load was close to the designed HP, that means there will be less torque, more slip and more heat in the motor, it will overload. If your motor was at least 20% over sized for the load, you might be OK though.

If it is 400V nominal, the V/Hz ratio works out to be roughly the same as a 460V 60Hz motor, so other than the speed change (see Load) then its likely OK.

 

[iwire]

Load? If it's a centrifugal pump, probably a deal breaker. Centrifugal pumps will increase the HP requirement at the cube of the speed increase. So 50-60Hz is 120% speed, the pump will require 1.2x1.2x1.2 = 173% of the original HP. The motor HP will increase 20%, but unless that motor started out being grossly overnsized, it won't work.

How about if you restrict the flow?

 

[Jraef]

How about if you restrict the flow?

That works, but decreases efficiency.

 

[kwired]

if the load is a motor driven by a VFD you can change some paramaters and be good to go in many cases.

 

[Joethemechanic]

Trim the impeller in a lathe. Rule of thumb is to cut it so the velocity of the circumference is the same as when it ran at a slower speed. Although you can very easily end up with a pump with a different curve due to the relationship between the impeller and the volute

 

[Jraef]

if the load is a motor driven by a VFD you can change some paramaters and be good to go in many cases.

Yep, should have put that in the flow chart too.