VFD For Submersible Pump

One of the possibilities is a mismatch between the selection of the VFD and the motor it is supposed to be driving.

Switch back to reduced voltage auto-transformer starting, perhaps?

Reported : Spam

* Is the motor rated for VFD duty?

* Pumps with high static head requirements, such as submersible well pumps, are often not good candidates for variable speed installation in the first place.

Get rid of the VFD and match the pump to the system requirements.

One of the possibilities is that the fluid being pumped forms part of the cooling arrangements for the VFD, and the speed of the pump is insufficient to deliver the correct flow. Then, no-one here can see the installation other than the original poster...

The pump is a 50hp the starter used is reduced voltage auto-xformer and when we replaced by VFD the vfd is turning hot always what cause this? Your Message: Hello. You don't need a VFD for that pump. Based on the data you provided, the load was designed to run via a reduced voltage auto-transformer circuit. Then, get a soft starter. The soft starter solves that problem for you. It will help in regulating the voltage RAMP without altering the stipulated supply frequency. Follow the wiring instructions carefully. Surely the challenge you are having will be overcome.

Dear Mr.jhunair,

The data given by you is not sufficient to understand the problem. Pl. post the following information .

1. What is the need for VFD for submersible pump.? Whether it is 6 Pulse or 12 Pulse.?

2. Is there Harmonic Filter installed.?

3. What is the detail for earthing.?

4. Whether the Motor is suitable for VFD application, such as Bearing Insulation or Insulated Bearing.?

5. Whether De-Rating Factor is considered as applicable.?

6. What is the distance between the Drive and the Motor i.e the cable length.? Whether the cable is grounded.?

7. Whether the Blower inside the VFD installed has adequate capacity.?

Once these details or known we can think of a solution.

DHAYANANDHAN.S

Additionally, submersible pumps have lower efficiency than conventional motor-pump groups (stator windings work under water, thicker wire insulation, aspect ratio not ideal). So 50 hp means higher electrical power. Check measured kW and amps vs. VFD spec.

Also the hydrodynamic bearings are not designed for lower rpm, so a soft starter suits best your application.

Sorry, what I mentioned above for the bearings vs. rpm applies to vertical well pumps, not for submersibles.

Hi,

The RVAT is for starting purposes and nothing else. VFD is for those system that needs variation in speeds and torques.. So, what is your requirement? If for starting only then you need a soft starter..

Hello Sirs,

Thank you very much for your inputs, we put back again the RVAT starter because the vfd causes us problems we need full speeds since the demand of water is large.