9 Tips to Avoid Vertical Multi-Stage Motor Failure


Below are 9 tips to avoid VMS motor failure, written by Franklin Electric’s Steven Ulrich, Senior Portfolio Manager for Large Surface Pumps.

  1. Know your max flow and head requirements, and then properly size your VMS pump according to your application pre-installation.
  2. A VFD does not give your VMS pump supernatural abilities. Overloading can still occur if the pump is not sized properly. Ensure your overloads are set properly to take the pump offline should a problem develop.
  3. When setting up a pump system to be controlled by a VFD, follow the VFD manufacturer's guidelines VFDs - Steve Ulrich Storyconcerning the need for output filtering to reduce damage to the motor insulation system from voltage spikes. Using a motor with a Class F or H insulation system would give the motor a higher temperature rise rating and ensure the insulation holds up better under warmer operating conditions.
  4. Properly set up the throttling valve at pump startup if the transducer and PID feedback are not monitoring the pump’s discharge side.
  5. One option is to install a fixed orifice flow control valve on the pump discharge line to prevent it from going beyond its recommended operating range.
  6. Follow the manufacturer owner's manual closely and test repeatedly.
  7. To achieve results backed by proper testing, partner with one manufacturer (for both the VMS pump and the VFD) that tests the products working together and can prove their performance.
  8. When buying your VMS and VFD, choose a manufacturer with a proven history of on-site product support to ensure future challenges or questions are quickly resolved and maximum performance is continued.
  9. When using a VFD on any pump, including a VMS pump, bearing failure from VFD-induced shaft voltage and the resulting bearing currents can be prevented with the use of ground shaft rings, or it can be reduced significantly with the use of a dv/dt filter.

To read the full article on Tips to Get the Most from VMS Pumps, click here.