Hi,

I am trying to power a vacuum pump with a VFD (see attached photo). The pump was previously connected to a heater and should be powered by three phases. When running at 220 V and 50 Hz, it consumes about 660 W. On the pump, there is a plate that indicate power consumption of 370 W. Moreover, it turns quite slowly. The wiring was made according to the VFD manufacturer, although there may be a mistake because I had to guess which wire is which since there is no label. It should be wired in delta mode, since there is around 50 Ohm in between U,V and W and open between U,V,W and the neutral. Is the motor faulty? Where did I make a mistake?

Do not hesitate to ask if more info is needed,

Best,

DD

 

Please send a picture of the motor nameplate, information about the motor protection setting, mains voltage and pump data. Is there a vacuum valve to prevent overloading.

 

I linked a picture of the motor nameplate and the switch on top. I do not know anything about the protection settings unfortunately...
The mains voltage is 230V at 50Hz. After the VFD, there is 230V between each U,V and W.
The pump is an Alcatel 2005.
Best,
DD

 

How are you using the 3ph Hager contactor unit?

 

Well I am just making sure it is ON... I recovered this pump from a dumpster and have no experience with three phases (and just basic electricity knowledge). The pump was attached to a broken diffusion pump. Two cables come out of the switching box on top of the rotary vane pump. One cable with a 3 wire connector wass connected to the heater of the diffusion pump. Another cable has 5 wires, and I connected this one to the VFD with U,V,W,N,GND.

 

Motor is probably connected in star. You can change to delta by connecting:
Hager-1: Motor-U1
Hager-3: Motor-V1
Hager-5: Motor-W1
Hager-2: Motor-W2 and VFD-U
Hager-4: Motor-U2 and VFD-V
Hager-6: Motor-V2 and VFD-W

VFD has no N, just 3 phases and ground.
Do not use the Hager motor protection as pump start/stop, use control inputs on the VFD instead. There are probably also settings in the VFD that need to be done.

 

Here is a scheme of the wiring. I wrongly connected the neutral to the unconnected pin on the 5 pins connector. Also, there is another hager unit, which seems to just connect 14 to 13 when the motor is connected.
That means that, for the motor, the wiring is already like the one you suggested. It still uses 660W instead of 370W and spins slowly. I hope this scheme help clarify the wiring...

 

It is not the same wiring, your motor should have 6 wires that you can connect Hager, see attached.
370W is the motor output. Calculated from the rating plate, the full load consumption will be 530W. Better look at current consumption, max 1.9A

 

I agree with BVSM that the motor is probably wired in star configuration (400 volts phase to phase. )
Your VFD will be supplying 230 volts phase to phase so you need to re configure the windings in delta.
But I would not use the M506 for overcurrent protection, I would configure the VFD to provide this protection.
The M520 is not part of the motor control so it is not needed.

Les.

 

Indeed there was three wire tucked behind the contactor, all linked together. After wiring them as you suggested it runs fine at 1.3A. Thank you all for your help!