use non VFD deep well water pump with inexpensive VFD drive?

stevehull

I read, earlier this AM (on this forum), of a guy that was tyrying to soft start a deep well pump and all the advice that was offered. One of the things I saw was a VFD drive for just a couple hundred $ that was capable of driving a 1 HP (think BB posted this).

Now I can't find that post!!

Anyway, there is a lot of debate on VFD vs non-VFD pump setups on other water well pumping forums. Most of the old school well drillers do NOT like the VFD drives.

But it seems like this is a perfect marriage to allow the lowest power to provide water power?

Asking for advice/thoughts on doing the above.

Thanks in advance,

Steve

stephendv

Re: use non VFD deep well water pump with inexpensive VFD drive?

The other thread is here: http://forum.solar-electric.com/showthread.php?14464-Soft-start-options-for-a-deep-well-pump&p=144082

In my opinion, VFDs are a good choice for a number of reasons:
- A 3 phase pump is usually a bit cheaper than a single phase
- 3 phase is more reliable
- You can program the VFD to start the pump up extremely slowly, which not only reduces inrush current, it also reduces the stresses on the pump = longer pump life.
- You can choose to operate the pump at different speeds, e.g. half speed for twice the time which could also improve pump life
- VFDs offer some built in protections that aren't there with a hard wired pump, e.g. low water level switch, configurable overcurrent protection.

Blackcherry04

Re: use non VFD deep well water pump with inexpensive VFD drive?

Try this thread also.

http://forum.solar-electric.com/showthread.php?16078-Help-required-to-design-off-grid-system

BB.

Re: use non VFD deep well water pump with inexpensive VFD drive?

I have a machinist friend that has used VFDs on his equipment. I think his feeling is the motors may be a bit less reliable on a VFD. (VFD's may be MSW output--at least for the less expensive versions). If you have a motor running near rated output power--A MSW wave form can increase power draw by ~20%--which is waste heat in the motor.

That is my concern/question.

What have the pumping forum issues been?

-Bill

peakbagger

Re: use non VFD deep well water pump with inexpensive VFD drive?

Its really hard to buy a low horsepower VFD that put out single phase. There are quite few sold that go the other way, single phase in 3 phase out but very few that output single phase.