50Hz to 60Hz

[conmgt]

I've been asked to install an Italian CNC lathe for a customer who makes custom baseball bats.

The spec sheet says "34.81Kw - 400V - 50Hz - 71.1A"

In my quick conversion to 208V I'm going simply with the 34.81Kw and coming up with 96.6A on my ElectriCalc which is much less than my guess of it being twice the 71A since 208 is about 1/2 of 400V.

If I try 34.81Kw at 400V I get 50A on my ElectriCalc. 400V, 71.1A gets me 49.25Kw and 49.25Kw at 208V gets me 136.7A...closer to my guess.

I asked the US rep for this machine what the power requirements would be and he said that it would still be the 71.1A ???? He said he would be putting in a transformer to allow an input of 208V and that the A wouldn't change.

What effect on calcs does the 50Hz have?

 

[Jraef]

There is no generalized answer to that question. It depends on a lot of things.

Wiring systems used in IEC countries are different than what we tend to use. For example they may often expect the line voltage to be Y connected, so they will look for 400Y230V and sometimes the single phase voltages they use internally will be line-to-neutral to get 230V, something you will need to address in the transformer selection even before dealing with frequency issues. You will have to get hold of a detailed wiring diagram and evaluate each component individually, based on the specs of that component only.

For example, 400V 50Hz AC motors can usually tolerate having 480V 60Hz applied to them because the V/Hz ratio is close enough to provide the rated torque, but the motors will spin 20% faster. But if the motors are on VFDs, it may make no difference whatsoever, the VFD will output the same thing regardless of the higher input voltage and frequency. If there are servo and/or stepper motors, you have to look at the input power requirements of the amplifiers. Most of them rectify the input anyway, just like on a VFD, so input frequency may be irrelevant there too. Same thing for DC motors and controllers. 24VDC Power Supplies for any electronic controls may also be frequency independent and many of them are also input voltage switchable. But AC controls may be a problem, some older AC coils on contactors and relays may not operate correctly (or for long) if the frequency is different.

 

[Besoeker]

I've been asked to install an Italian CNC lathe for a customer who makes custom baseball bats.

The spec sheet says "34.81Kw - 400V - 50Hz - 71.1A"

71.1A gets me 49.25Kw

It gets you 49.25 kVA which is not the same as 49.25 kW.
The figures from the specification indicate a power factor of about 0.71.

The 50Hz/60Hz doesn't change the calculation of power - for three phase it is still sqrt(3)*VL*IL*cos(phi).

But, as Jraef has pointed out, you need to look at each part of the machine to determine whether the difference in frequency could present a problem.