# VFD w/ single phase motors



## Ray Cyr (Nov 21, 2007)

Empowered said:


> It's been awhile since I toyed around with VFD's in school so I'm a bit foggy on the subject. Here's the problem. My friend lives on an acreage and has pond water. He is buying a new water softening system and Culligan is telling him he needs to buy their $2500 aeration pump so that it is compatible with their VFD. Is this true or will his current single phase pump work regardless?


I don't have enough information to answer your question but I will say that your friend needs to proceed with caution. Not doing what Culligan says needs to be done "may" void their warranty.


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## Empowered (Apr 12, 2010)

I agree that it 'could' void his warranty, but realistically wouldn't the only thing that could be damaged is the old pump motor?


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## wildleg (Apr 12, 2009)

not enough information


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## Empowered (Apr 12, 2010)

Ray Cyr said:


> I don't have enough information to answer your question but I will say that your friend needs to proceed with caution. Not doing what Culligan says needs to be done "may" void their warranty.





wildleg said:


> not enough information



What kind of info would help you guys?


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## MDShunk (Jan 7, 2007)

My 2 cents on Culligan is to kick them to the curb. I've had several bad experiences with them. There is no special hocus-pocus in their brand equipment, and you can get the same result for cheaper by going with a local water conditioning company. This will also give you the advantage of having a system built of fairly generic parts, should any piece of it require replacement. 

Probably the only benefit to going with Culligan is the ability to make monthly installments on the system.


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## electro916 (Jan 16, 2009)

You cannot speed control a capacitor start motor. So If the motor in question is capacitor start you will not be able to use it with the VFD.


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## Wingnut (Jan 31, 2010)

we put in couple temporary conveyors that had to have drive rated motors 

1 HP and it required 18 amp per drive


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## Wingnut (Jan 31, 2010)

what is "their" VFD


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## John Valdes (May 17, 2007)

Does he have three phase or single phase? You cannot use a VFD on a single phase motor.


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## JohnR (Apr 12, 2010)

I would take a second opinion on your water situation. 

I bought my dad's house he was using the service you named and always was somewhat dissatisfied with the quality. I installed my own and am completely satisfied with the clarity of the water. 

I second the kick them to the curb idea.


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## MDShunk (Jan 7, 2007)

One of the major problems with Culligan, in my opinion, is that whatever their latest and greatest technology is, that's what everyone suddenly needs. Sometimes a simple approach offers the best solution. That approach doesn't always need to have Culligan's name on it.


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## Mr.C (Dec 20, 2009)

Most likely they are supplying your friend with a three phase motor which can be driven by a single phase supply if you use a vfd to drive it. So no your friends single phase pump motor will not work on the drive. Now here is the deal, if culigan is using the drive only to create the three phase output for the motor and they are not using variable speeds then your friend can use his own motor if the speed is the same as culigans specs. Now your probably wondering why they would even specify a three phase motor in the first place, well you can get more horse power out of a three phase motor that is the same size physically as a single phase motor and they will draw less current which means you dont have to use large conductors which means cheaper installation or a product that is more compatible with existing residential power supplies. Anyways the point is they probably have a small vfd in their system and the output to the motor is three phase, so the special culigan motor is more than likely a three phase motor. If you hook up your friends single phase motor to it wont work. Also if they are using a single phase motor that is driven by the vfd then it wont have a capacitor in the start or run circuit and I would bet your friends motor is at least a cap start motor which would freak out a drive after the centrifugal switch kicked it out so don't use your buddies motor unless you are sure of the output of the culigan power supply. Please let us know what model of culigan whatever it is for it would be interesting to chack it out online.


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## kingull (Jan 2, 2012)

Empowered said:


> It's been awhile since I toyed around with VFD's in school so I'm a bit foggy on the subject. Here's the problem. My friend lives on an acreage and has pond water. He is buying a new water softening system and Culligan is telling him he needs to buy their $2500 aeration pump so that it is compatible with their VFD. Is this true or will his current single phase pump work regardless?


If the motor is PSC (Permanent split capacitor), it may work.
Switch start motors are unlikely to work.

PSC are two winding motors: Main and auxiliary.
The auxiliary winding is matched to a capacitor to achieve high efficiency and lower line current.

Centrifugal pumps and centrifugal fans are (Variable torque).
Horsepower required is to the cube of change in speed.
Conversely, a reduction in frequency (reduces speed) and at half speed your motor load would be 0.125% of the normal RPM.

VFD`s are normally one phase in and 3 phase out. I have only found one that is one phase out and a bit pricy.

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http://www.temcoindustrialpower.com/products/Variable_Frequency_Drives/V00003.html
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