How Do I Select The Proper Surge Suppressor?

I would contact the manufacture of the valve assembly for their recommendations.

I would also contact the power company and find out why they have spikes in their supply and what they are going to do about it.

Contact a consultant or supplier of SPD to inspect the installation and recommend.

Hi there, would a 3-phase constant voltage transformer not cure these issues

I'd have a "whole house" type of surge protector installed. Not one on each load. Protect ALL your electronics not just the motors electronics if you have known spikes in your service.

Is the motor failing or the controls for it?

GW,

The answer is both. 1st time - the motor failed along with the controls. The 2nd time - just the controls failed. I originally thought that the heat from the motor failure caused the problem with the controls, but, motor was O.K. the 2nd time it happened.

Thanks.

What is your control?

VFD?

Contactors?

Frequency of operation?

Damage that occurred?

Do you have any pictures?

I would definitely get the utilities involved with this and maybe have them compensate you for the lost motor and controls, that's just not right at all. Maybe you guys should pay your utility bills with negative spikes??

It may be hard to prove it was a voltage spike. It may be an assumption right now. It would take a power quality monitor to prove that.

I have seen standard controls using just contactors single phase because the contactor did not pull in square and subsequently burn up a mess of hardware. That was even with protection to code requirements.

We have available in our country both IEC contactors and NEMA rated contactors. The NEMA contactors are 2 or 3 times larger, but appear to run for ever compared to the IEC that seem to burn up at the most awkward moments.