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#### Eng.Falcon

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I want to purchase a pumper with these specifications:

5.5 Kw - 400 V - Three-Phase (3ph) - 50 Hz

My question is: What should happen, or be changed when I need to change the frequency to ( 60 hz )?

Respects,

#### erics37

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A VFD would be able to run that at its nameplate values just fine and you wouldn't have to even worry about running it at 60 Hz.

#### Eng.Falcon

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While a VFD might work, the company told me that they would be able to change the machine's frequency to 60Hz. However, when inspecting the machine, what voltage or other values should I look for to make sure the machine won't overheat or work in under-performance?

#### metalpats

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since it is an induction motor, the frequecy should be proportionnal to the voltage, so the voltage should be 60/50*(voltage at 50 hz on nameplate)

#### Eng.Falcon

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so, when I apply the
60/50*(voltage at 50 hz on nameplate)
equation to get 480~V, there should not be anything else to be changed in the machine like external and internal wires and so on so fort, right?

#### JRaef

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so, when I apply the equation to get 480~V, there should not be anything else to be changed in the machine like external and internal wires and so on so fort, right?
Yes, technically correct.

However...

You say this is a "pumper". What exactly does that mean? Because if this is a CENTRIFUGAL pump driven by an electric motor, you will potentially have a major problem. In a centrifugal pump, the power that the pump demands from the motor at a new speed is a factor of the CUBE of the speed change. So if the motor was sized for use at 50Hz, and you run it at 60Hz, then the PUMP will be running at 120% of design speed. That means that the pumps will REQUIRE more power from the motor at the CUBE of that, so 1.20 x 1.20 x 1.20, or 173% more power. The motor is ALSO running faster and at a higher voltage, thereby putting out more HP, 120%. But it is not increasing it's power as fast as the pump is demanding it. So your pump is now going to overload that motor by over 50%.

If there is a valve on the piping from or to the pump someplace, you might be able to turn down the flow through the pump in order to decrease the load, and in theory, the flow point would be the same as it was at 50Hz, so you may not actually lose anything here. But without that capability, you will not be able to run it.

If it is NOT a centrifugal pump, this does not apply.

#### Eng.Falcon

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It is indeed a centrifugal pump.