Intellidrive PID30 slow ramp up

[RandomPotato]

https://imgur.com/a/btbdCMa

My Intellidrive PID has a slow starting ramp-up time. Is there a way to make the soft start more aggressive? I’ve tried tuning the PID parameters, but it hasn’t helped. As a result, I often get a “Cannot Start Motor Fault.” A true jam should be 40A+, but the pump runs fine if the VFD will exceed 30Hz in a few seconds. Often, it fails around the 25-27Hz range on the Running Fixed Press Mode. I have a Franklin 2HP, 1Phase, 3 Wire Motor attached to the PID.

 

[Valveman]

Most likely the thrust bearing in the motor is damaged. The Kingsbury type bearing has no lubrication below 30hz. Any VFD should get the pump to 30hz within 1 second or the thrust bearing will be damaged, which is usually the case when you try to soft start a submersible motor. You would not be having problems with a Cycle Stop Valve instead of the VFD, which is exactly why installers prefer VFD's.

 

[Sponsor]

 

[RandomPotato]

Most likely the thrust bearing in the motor is damaged. The Kingsbury type bearing has no lubrication below 30hz. Any VFD should get the pump to 30hz within 1 second or the thrust bearing will be damaged, which is usually the case when you try to soft start a submersible motor. You would not be having problems with a Cycle Stop Valve instead of the VFD, which is exactly why installers prefer VFD's.

It’s interesting that the pump is only a year old so I would hope its not dying already, and we recently switched to a VFD about a week ago. We haven’t encountered any issues with the traditional pressure switch system. Would checking the ohm resistance provide any information about the pump’s health?

I did just order a CSV for my other pump project, I'm excited to see it in action.

 

[Fitter30]

model number take a pic of it

 

[RandomPotato]

model number take a pic of it

Pentek PID30

https://imgur.com/a/hI0O5NE

 

[Fitter30]

Proportional gain of thTing e pid loop adjusts the speed of the loop. Default is 1500. Wonder if the power needs to be cycled to lock new setting in.

 

[Valveman]

Like I said, there is no film of water between the pads and plate on a Kingbury thrust bearing until the motor is over 30hz or half of full speed. Even if the thrust bearing is not damaged yet, it is still sticking at 27hz because there is no lubrication. You should not even be able to see 27hz. It should basically start at 30hz and slow start from there to 60hz.

You were not having any problems with the traditional pressure switch system. So, why did you switch to a VFD?

 

[RandomPotato]

Like I said, there is no film of water between the pads and plate on a Kingbury thrust bearing until the motor is over 30hz or half of full speed. Even if the thrust bearing is not damaged yet, it is still sticking at 27hz because there is no lubrication. You should not even be able to see 27hz. It should basically start at 30hz and slow start from there to 60hz.

You were not having any problems with the traditional pressure switch system. So, why did you switch to a VFD?

Two years ago, I bought a house with a 67-foot well from the 1970s. A local installer inspected the motor/pump last year and found it faulty. He replaced it with a FE motor and a 15 GPM pump, but the well’s static remained around 60 feet. Since then, the house and irrigation system have been problematic.

This January, we drilled the well to 170 feet, but the 15 GPM pump still caused issues. We swapped it back to a 35 GPM pump, which resolved the problems, but it drew down the well too quickly. (I have a WellWatch 670 on the well) The well produces around 28 GPM, so it was recomended to install a VFD to allow irrigation in the 20s with a bit of wiggle room but not draw things down too qucikly.

 

[Valveman]

Two years ago, I bought a house with a 67-foot well from the 1970s. A local installer inspected the motor/pump last year and found it faulty. He replaced it with a FE motor and a 15 GPM pump, but the well’s static remained around 60 feet. Since then, the house and irrigation system have been problematic.

This January, we drilled the well to 170 feet, but the 15 GPM pump still caused issues. We swapped it back to a 35 GPM pump, which resolved the problems, but it drew down the well too quickly. (I have a WellWatch 670 on the well) The well produces around 28 GPM, so it was recomended to install a VFD to allow irrigation in the 20s with a bit of wiggle room but not draw things down too qucikly.

Making a 35 GPM pump produce less than 35 GPM without cycling the pump on/off should be the perfect application for a VFD. I thought the same thing about 1990 and started using VFD's. However, things that work on paper don't always work in real life. If every well had a 3HP, 35 GPM pump set at 67' with a static of 10' and needing to produce 50 PSI constant, a VFD could be built and programed to work properly. But every pump system is different. They have different horsepower motors, different GPM pump ends, set at different depths with different static water levels, and require different pressures for different applications. Every VFD would have to be programed for each particular application. Those are very complicated settings and pump guys don't even know how to do that. So, they make VFD's like the PID that don't really vary the pump speed. If I remember correctly the Pentair PID shuts the pump off anytime it has run at the same speed for 60 seconds. If the pressure drops, it knows you are still using water and ramps the pump up again. If the pressure stays the same, it knows you are no longer using water and doesn't turn the pump back on. When water is being used this causes the pressure to drop rapidly every 60 seconds. Then the pump is started and causes a pressure spike trying to catch up again.

Because of all the problems I was having I came up with the Cycle Stop Valve to replace VFD's. Since 1993 there have been many thousands of VFD's replaced with a CSV, and all the problems go away.

It would be best to remove the VFD and use a normal 3HP control box and let a Cycle Stop Valve vary the flow and deliver constant pressure. However, the CSV will even work WITH a VFD. Just put the set of the VFD 10 PSI higher than the set point of the CSV. With the CSV set to hold 60 PSI, the system will never get to the 70 PSI set point of the VFD, and the pump will just run at normal speed. When no water is being used, a small amount will pass through the CSV to fill the pressure tank to 70 PSI, where the VFD can ramp the pump down and shut it off and it will stay off.

 

[Bannerman]

You should not even be able to see 27hz. It should basically start at 30hz and slow start from there to 60hz.

The VFD rating plate seems to confirm the 30hz design minimum as it it lists the output as 0-230 volts (30-80 Hz) when using a 3 phase motor, 0-230 volts (30-60 Hz) for a 1 phase, 2-wire motor, or 0-290 volts (30-60 Hz), for a 1 phase, 3-wire motor.

Perhaps your VFD controller is defective, or as Valveman suspects, a damaged thrust bearing in the pump is causing excessive drag which is resulting in the system attempting to operate outside the design parameters.

Since your VFD is only a week old, perhaps you will be able to return it for the reason of possible defect or incompatibility with your pump. I would then suggest for simplicity and reliability, equipping your system with a CSV controlled by a standard pressure switch.

 

[RandomPotato]

(sorry for the late reply, looks like my previous message didn't post)
So I'm gonna swap out the Pentair with a Fraklin as suggested by another installer and see how that goes, as for adding a CSV how does the pump function when the CSV reduces the flow? If the pump is rated for 35GPM but the CSV only allows 1 GPM won't the pump continue to build pressure until it can no longer pump? Won't that damage thigns?

 

[Fitter30]

Doesn't matter how high a vfd's HZ can go to can't over amp a motor name plate amps. Have talked to the vfd manufacturer tech line? Every vfd will have a service setting to get into factory setting. 3 phase motor can run in either direction. Vfd can be programmed to run in either.

 

[Valveman]

(sorry for the late reply, looks like my previous message didn't post)
So I'm gonna swap out the Pentair with a Fraklin as suggested by another installer and see how that goes, as for adding a CSV how does the pump function when the CSV reduces the flow? If the pump is rated for 35GPM but the CSV only allows 1 GPM won't the pump continue to build pressure until it can no longer pump? Won't that damage thigns?

The CSV needed for a 35 gpm pump will have a minimum flow of about 3 gpm because that size pump needs 3 gpm to remain cool. But at 1 or 3 gpm the motor is drawing lower amps and running cooler than at high flow. Back pressure is good for pumps. Back pressure reduces amps and eliminates cycling, which are what destroys pumps. The back pressure from a CSV will greatly extend the life of the pump.