Arlen Angell
New Member
I recently put in a new 3Hp 3 phase pump and a Pentek PID30.
The pump is set at about 380 feet, well is bored and cased down to 560 feet.
The static water level is 320 ish feet.
Drop pipe is 1.25 schedule 40 steel
Pressure tank is 60 gallon charged to 47psi
Pump is a Webtrol WT1030-L
The well contractor installed everything but the VFD. Drives and automation are my field of expertise, and the contractor told me it would work good with the defaults. It does for the most part.
I have a few questions/observation that I’m hoping some of you can help me out with.
1) The service factor amps for the motor is 10.1, however the pump running at 60hz will move about 15gpm at a pressure of about 20 psi at the surface. This seems to fit with the pump curves. Problem is the motor will run at 12 amps! The contractor told me I would get 14-15 GPM, but I assumed that I wouldn’t have to over amp the motor to get it
I have set the max freq in the drive to 55 hz. This gets me about 12 gpm, and puts the amps at about 9.5
Question: Is that the best way to handle it? Should a different pump have been selected?
2) What is the proper way to determine the proper minimum freq? Default is 30hz, but the pump doesn’t seem to move water at 45hz and below (it doesn’t build pressure with no water flowing)
3) The pumped seemed to react a little too quick (maybe because of the large pressure tank), so I lowered the prop band to 1000 in the pid setup. It seems to run better.
Question: Any advice on setting the integration and derivative ?
4) When I have a faucet running...maybe 1 or 2 gpm, the drive will slow down to 47 hz and hold 60psi perfectly. I would expect that it would run like this forever. However after awhile, I suppose when the wake delay expires, the drive will go into the pressure boost mode, then go to sleep. Then it drops down to the 55 psi mark, and the whole process starts again. That seems to diminish the value of having a drive. The pump actually probably cycles more with the VFD than with the single speed system.
Question: Is this a necessary evil, or can that behavior be adjusted out?
That should be enough to get a conversation going
The pump is set at about 380 feet, well is bored and cased down to 560 feet.
The static water level is 320 ish feet.
Drop pipe is 1.25 schedule 40 steel
Pressure tank is 60 gallon charged to 47psi
Pump is a Webtrol WT1030-L
The well contractor installed everything but the VFD. Drives and automation are my field of expertise, and the contractor told me it would work good with the defaults. It does for the most part.
I have a few questions/observation that I’m hoping some of you can help me out with.
1) The service factor amps for the motor is 10.1, however the pump running at 60hz will move about 15gpm at a pressure of about 20 psi at the surface. This seems to fit with the pump curves. Problem is the motor will run at 12 amps! The contractor told me I would get 14-15 GPM, but I assumed that I wouldn’t have to over amp the motor to get it
I have set the max freq in the drive to 55 hz. This gets me about 12 gpm, and puts the amps at about 9.5
Question: Is that the best way to handle it? Should a different pump have been selected?
2) What is the proper way to determine the proper minimum freq? Default is 30hz, but the pump doesn’t seem to move water at 45hz and below (it doesn’t build pressure with no water flowing)
3) The pumped seemed to react a little too quick (maybe because of the large pressure tank), so I lowered the prop band to 1000 in the pid setup. It seems to run better.
Question: Any advice on setting the integration and derivative ?
4) When I have a faucet running...maybe 1 or 2 gpm, the drive will slow down to 47 hz and hold 60psi perfectly. I would expect that it would run like this forever. However after awhile, I suppose when the wake delay expires, the drive will go into the pressure boost mode, then go to sleep. Then it drops down to the 55 psi mark, and the whole process starts again. That seems to diminish the value of having a drive. The pump actually probably cycles more with the VFD than with the single speed system.
Question: Is this a necessary evil, or can that behavior be adjusted out?
That should be enough to get a conversation going
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