# Variable Speed Conrol- Pump



## MTW (Aug 28, 2013)

Not in my area, though I did hook one up early in the summer. My area has a short pool season so the payback would be pretty long for a VFD pump. Now Florida on the other hand..

That being said, I have heard they are mandated in some states because of energy codes, and surely California requires them by now.


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## dronai (Apr 11, 2011)

MTW said:


> Not in my area, though I did hook one up early in the summer. My area has a short pool season so the payback would be pretty long for a VFD pump. Now Florida on the other hand..
> 
> That being said, I have heard they are mandated in some states because of energy codes, and surely California requires them by now.


You hooked up an all in one variable pool pump, or a vfd controller to control the pump ?


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## splatz (May 23, 2015)

Do pool pumps run at variable speeds / loads? I am having a hard time seeing a drive being necessary to get optimum efficiency if the load is constant.


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## Forge Boyz (Nov 7, 2014)

I just talked to a guy from pentair today and he said that depending on what you are doing with the pump it will run different speeds. We didn't get into what those different things were, but I'm assuming its things like filtering, while you are in the pool and maybe like a sleep cycle or something. Just my assumptions. The pump nameplate speed said from 430-3540 (I think).

Sent from my SM-G970U1 using Tapatalk


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## MTW (Aug 28, 2013)

dronai said:


> You hooked up an all in one variable pool pump, or a vfd controller to control the pump ?


It was an all in one unit. I thought it was a waste of money, but the pool contractor sold it to the homeowner.


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## dronai (Apr 11, 2011)

splatz said:


> Do pool pumps run at variable speeds / loads? I am having a hard time seeing a drive being necessary to get optimum efficiency if the load is constant.



It's kind of a newer thing. You pump at 100% for a few hours to filter the pool, 
and 1/2 the power for the remaining time to just circulate the water. All of this to save money on electricity consumpsion.



https://www.poolsupplyunlimited.com...MIuo3wyufb5QIVx0XVCh3x_ARfEAQYASABEgKFBvD_BwE


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## dronai (Apr 11, 2011)

Forge Boyz said:


> I just talked to a guy from pentair today and he said that depending on what you are doing with the pump it will run different speeds. We didn't get into what those different things were, but I'm assuming its things like filtering, while you are in the pool and maybe like a sleep cycle or something. Just my assumptions. The pump nameplate speed said from 430-3540 (I think).
> 
> Sent from my SM-G970U1 using Tapatalk


Filtering, and just circulating water at 50%


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## gpop (May 14, 2018)

dronai said:


> Has anyone tried to use a VFD on their pool pump motor ?
> 
> I have a VFD, I might give it a go, and measure the output.
> 
> ...



The vfd is converting single phase to 3 phase. 

Alot of people think a vfd only controls the speed but it also controls the output voltage, power factor and wave form shape. Amps (output) are more of a result and do not really tell you how much power the motor is using. 

Measuring the input amps can give you a better idea of the power being used as the voltage is constant. Compare that against a standard pump amp draw for the same HP and you will see a difference.


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## varmit (Apr 19, 2009)

If you have a single phase pump motor, a VFD will not work. If you have a single phase service you could supply a properly down rated VFD with single phase and run a three phase pump motor.


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## NoBot (Oct 12, 2019)

The variable speed pool pumps I've wired have been controlled by a Hayward OmniLogic system control. It controls filter pump speed, lighting, PH, chlorine, filtration, hot tubs, salt, etc.
It can also be controlled by a phone or tablet.


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## dronai (Apr 11, 2011)

varmit said:


> If you have a single phase pump motor, a VFD will not work. If you have a single phase service you could supply a properly down rated VFD with single phase and run a three phase pump motor.


I have a powerflex 40, but I've only used it from a single phase supply, out to a 3 phase motor. 

So it won't work ?


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## varmit (Apr 19, 2009)

A VFD will only work on a 3 phase motor.


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## paulengr (Oct 8, 2017)

A Hayward variable speed pump is a 3 phase pump with a VFD on the back of it. Quick and simple.


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## dronai (Apr 11, 2011)

paulengr said:


> A Hayward variable speed pump is a 3 phase pump with a VFD on the back of it. Quick and simple.


Yeah, looks like that would be the way to go. But the return on investment is a lot of years :biggrin:


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## paulengr (Oct 8, 2017)

dronai said:


> Yeah, looks like that would be the way to go. But the return on investment is a lot of years :biggrin:



That’s true of all VFDs when they are optional.


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## dronai (Apr 11, 2011)

Most residental pool pumps are single phase. I wonder if this guy tried it on a single phase motor, and that's why he had Amperage loss.

http://https://www.instructables.com/id/Save-Money-with-thisInverter-variable-speed-mod-t/


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## JRaef (Mar 23, 2009)

Running a pump on a VFD takes advantage of the "affinity law" of pump speed, meaning that power (HP or kW) _*required *_by the pump varies at the _*CUBE *_of the speed change. So for example at half speed, the pump requires .5^3 (.5 x .5 x .5) of the power; 50% speed requires only 12.5% power. Now mind you SPEED and FLOW are not the same thing; flow change is usually lower than the speed change because of head pressure changes. So 50% FLOW may actually equate to a higher speed , i.e. 70% pump speed (it varies for each installation). But the energy savings are for real and in pools, spas etc., the issue is that MOST of the time they can run at lower speeds, only needing the high speed for sweeping applications or when the heater is running.


You can actually run a single phase motor from a VFD, until one of them dies on you, and it's a race to see which one. Most of the single phase motors have starting capacitors, which to the VFD look like a short circuit, potentially damaging the transistors. From the motor side, the harmonics created by the VFD get absorbed by the capacitors, over heating them. Plus there is the issue of the centrifugal switch, because if you don't get to the speed at which the switch opens or you slow it down to below that speed, the starting caps stay in the circuit too long so the demise of one or the other happens even faster. In addition, many VFDs, because they are designed for 3 phase output, will trip on output phase loss if you connect them to a single phase motor.


There ARE companies that make VFDs that operate single phase motors, but they warn you to ONLY use them on PSC (Permanent Split Capacitor) type motors (because the capacitors are in series with a winding, but in parallel and there is no centrifugal switch) or on Shaded Pole motors, neither of which are used on pool pumps.


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## oliquir (Jan 13, 2011)

i prefer dual speed pumps, i have one for my pool and it is perfect and cheap to buy, i run it at full speed in day and low at night


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## JRaef (Mar 23, 2009)

oliquir said:


> i prefer dual speed pumps, i have one for my pool and it is perfect and cheap to buy, i run it at full speed in day and low at night


That's what I have on mine. It's worked flawlessly for almost 20 years now. I personally love VFDs, but sometimes simpler is better.


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## MikeFL (Apr 16, 2016)

JRaef said:


> ... I personally love VFDs, but ...


You dream about VFD's in your sleep!


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## dronai (Apr 11, 2011)

oliquir said:


> i prefer dual speed pumps, i have one for my pool and it is perfect and cheap to buy, i run it at full speed in day and low at night





JRaef said:


> That's what I have on mine. It's worked flawlessly for almost 20 years now. I personally love VFDs, but sometimes simpler is better.



Maybe this is the way to go. 

So that should be (2) sets of load connections to the timeclock, high speed, and load speed 240V outputs

Thanks for the input guys :vs_bulb:


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