Problems with Deep Well Pump and Low Frequency Inverter

[sunsurfer]

EDIT: wow, I just missed your update by minutes while I was typing...

Any update on the well pump? I read through "most" of the post, sorry if I repeat anything.

This is an interesting problem. You can hear a clicking noise when the pump surges and I am wondering if the clicking is from a centrifugal switch going back and forth from the start winding to the running windings then dropping back again? Hard to tell from the video.

How is the start capacitor?

LF inverters are good at dealing with reactive power but they also have real world limits. Could this pump be pushing back towards the batteries from the motor from reactive power overload and causing to much harmonics on the wave form making it surge? You would need an oscilloscope to see it.

I'm also wondering if any air bubbles in those long lines could cause weird motor harmonics. How about check to make sure the lines are full of water?

Keep us posted on how its going.

 

[sunsurfer]

Link to replacement pump.
There's no way that this pump is actually the 1HP rating it claims, as it takes ages to reach 50 psi from the customized cut-in pressure of 30 psi (stock cut on/off pressure is 20/40 psi, respectively) but it does draw about the same running wattage from other pumps in its class. However, for more than half the price of what's on offer at the duopoly, I'm going to buy a spare to spite them.

Yea, a deep well jet pump is not very efficient, standard jet pump is not very good either but they are durable and cheap. They aren't to bad for booster pumps. A submersible "centrifugal" pump will be more efficient then anything else but since you already have the two lines going down the hole, I think you did good just swapping in a new unit to get you going.

 

[1unluckyguy]

EDIT: wow, I just missed your update by minutes while I was typing...

Any update on the well pump? I read through "most" of the post, sorry if I repeat anything.

This is an interesting problem. You can hear a clicking noise when the pump surges and I am wondering if the clicking is from a centrifugal switch going back and forth from the start winding to the running windings then dropping back again? Hard to tell from the video.

How is the start capacitor?

LF inverters are good at dealing with reactive power but they also have real world limits. Could this pump be pushing back towards the batteries from the motor from reactive power overload and causing to much harmonics on the wave form making it surge? You would need an oscilloscope to see it.

I'm also wondering if any air bubbles in those long lines could cause weird motor harmonics. How about check to make sure the lines are full of water?

Keep us posted on how its going.

>Clicking noise
I don't know much about electric motors, so your guess is better than mine. It had to be something like like you mention, because it was a constant 4800 watt draw that would repeat. I have had a similar experience kill a gfci outlet using inverter power due to what I believe to be the higher quality sine wave causing a higher peak voltage than it was used to dealing with.
>Start capacitor
I still have the old pump, when I was triple checking my wiring trying to diagnose the issue, a cursory glance of the capacitor showed no obvious problems.
>Inquiries about reactive power effects
You seem to be much more knowledgeable on this subject than I. Sadly I do not have an oscilloscope to help you with that question, I just want to be able to shower without relying on decaying infrastructure.
>Concern about air in lines
The well isn't deep, and I take care to purge the system of air before using it. As you heard in the latest video, the new pump just starts, then maintains a steady function, so I doubt the existing piping is playing too much of a factor.

Thank God, the situation is now fixed. I hope that I can save someone in the future the multiple month headache that was my trying to fix the problem with everything but a new pump. I wonder if I could run this pump on just 2s1p now. I could lament the extra expense, but having more backup power is its own investment.

Good night!

 

[1unluckyguy]

Yea, a deep well jet pump is not very efficient, standard jet pump is not very good either but they are durable and cheap. They aren't to bad for booster pumps. A submersible "centrifugal" pump will be more efficient then anything else but since you already have the two lines going down the hole, I think you did good just swapping in a new unit to get you going.

Considering how much of a pain in the neck submersible pumps are to replace, and the extra cost, I don't see the appeal outside of the extraordinary situations that demand their application. Especially now that I installed unions, in theory all I would have to do to replace the pump going forward are to: Disconnect the unions, remove the fittings, apply new thread tape, install the fittings and reconnect the unions to get back to enjoying the life preserving qualities of dihydrous oxide.