Vfd for well pump

[Ganelmatt]

So tell us what you are trying to do, in more detail.
Why are you using a VFD?
Is the pump motor an existing motor?

I want to convert my current pump to a constant pressure pump with a vfd. I work at a wastewater plant and we have VFDs on everything so I was hoping to do the same to my well pump. I have a basic understanding on how it works, but just unsure of how to wire it up. I bought a Allen Bradley VFD that is for single phase 240v. I want it to work that when the pressure drops the pump comes on and ramps up and down with the demand

 

[Spoon]

What can you tell us about your well pump motor?
Any chance of a pic of the information plate.
Wastewater plants most prob use VFD's as the motors are variable speed. I can't see a plant not having 3 phase.
Depending on your motor you may not need a VFD and just start/stop the motor via a contactor operated by your sensor.
What sensor do you have? (or are looking at)

 

[Ganelmatt]

What can you tell us about your well pump motor?
Any chance of a pic of the information plate.
Wastewater plants most prob use VFD's as the motors are variable speed. I can't see a plant not having 3 phase.
Depending on your motor you may not need a VFD and just start/stop the motor via a contactor operated by your sensor.
What sensor do you have? (or are looking at)

I’m just looking, possible a 4-20 mv sensor

 

[Darkwood]

You can set drives up to search for a optimal feedback voltage/current that is user selectable, I would incorporate a pot' for either trimming and/or setting the pressure value, the VFD will then increase or decrease the speed of the pump until that pressure is realised as it looks for the voltage you set.
Although this can be easily set up as a basic program, you may find it gets more complex as you may need to change a few more complex parameters if the drive has them to ensure you don't end up with the drive going into cyclic hunting which will see the pressure rise and fall like a wave diagram, you can limit this sometimes with the pressure sensor choice (integral delays etc) as well as (if included) making changes to parameters in the drive.

 

[Ganelmatt]

You can set drives up to search for a optimal feedback voltage/current that is user selectable, I would incorporate a pot' for either trimming and/or setting the pressure value, the VFD will then increase or decrease the speed of the pump until that pressure is realised as it looks for the voltage you set.
Although this can be easily set up as a basic program, you may find it gets more complex as you may need to change a few more complex parameters if the drive has them to ensure you don't end up with the drive going into cyclic hunting which will see the pressure rise and fall like a wave diagram, you can limit this sometimes with the pressure sensor choice (integral delays etc) as well as (if included) making changes to parameters in the drive.

What is a “pot”?

 

[snowhead]

Potentiometer / variable resistor.

 

[Bobster]

It could be that you only require to run the motor at a fixed speed to produce your 60psi constant pressure, however, if the process is variable and it needs to tune itself. THe higher end Rockwell drives have built in PID functions that can use the 4-20mA signal from the pressure transmitter to ajust it's own speed accordingly.

 

[Ganelmatt]

It could be that you only require to run the motor at a fixed speed to produce your 60psi constant pressure, however, if the process is variable and it needs to tune itself. THe higher end Rockwell drives have built in PID functions that can use the 4-20mA signal from the pressure transmitter to ajust it's own speed accordingly.
I’m want to use a Allen Bradley 22-A4P2N113 Powerfex

 

[Bobster]

That particular model doesnt have PID capabilities.

I would install it, an using the dial on the front, see if a 60psi constant pressure is feasible without PID control.

If it isnt, then an Allen Bradley 820 plc will be the cheapest way to introduce PID control. An the software for it is free.

 

[Ganelmatt]

That particular model doesnt have PID capabilities.

I would install it, an using the dial on the front, see if a 60psi constant pressure is feasible without PID control.

If it isnt, then an Allen Bradley 820 plc will be the cheapest way to introduce PID control. An the software for it is free.

Ok thanks for all the help. Appreciate it