# VFD motor leads



## Charlie K (Aug 14, 2008)

I have an unusual situation and need some help. I have 6- 1.5hp pump motors that are 350' away from the drives. The drives are all located in one enclosure.I was curious if a seperate conduit run is needed for each motor. I have never done this in the past due to inductive coupling.
I do not know the VFD manufacture or have any info on the drives. The motors are located in a Class 1 div 1 area and I am looking to cut down on conduits.

Charlie


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## MDShunk (Jan 7, 2007)

Nope, but you're going to need load reactors and you should run VFD cable. 

C1D1... that sucks. Otherwise, you could just run a nice cable tray. There's no cheap or easy way to do this.


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## Charlie K (Aug 14, 2008)

MDShunk said:


> Nope, but you're going to need load reactors and you should run VFD cable.
> 
> C1D1... that sucks. Otherwise, you could just run a nice cable tray. There's no cheap or easy way to do this.


Thanks Marc, thats what I figured. I bid it as six conduits I was just looking to save some material and labor.

Charlie


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## MDShunk (Jan 7, 2007)

You can run a couple in each conduit, but if you're pulling drive cable, you probably don't want to subject yourself to that misery.


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## John Valdes (May 17, 2007)

I don't ever like to share a conduit feeding a motor from a VFD. I would run separate conduits and use THHN. Save your money on the over priced VFD cable, and buy conduit instead.
I would do a VD calculation (350') and increase the conductors as required. I would use load reactors as close to the motors as possible. I would pull an EGC in the conduit also.

I would also consider line reactors if you can get the customer on board. If they are familiar with VFD's, then they will tell you they want line reactors. Some VFD's have the line reactor included (built in) and some manufacturers will sell the line reactor at reduced cost or free if you buy the motor and drive from them. I know Baldor used to give you the line reactor for 1/2 price if you bought the drive from them and they would give it to you for free if you bought drive and motor from them? I am not certain. I would check that out.

While you can compliantly run these motor circuits together in one or more conduits, I just do not like doing it, even with load reactors installed. We don't mix signaling cables so why mix VFD output power. I think you would just be asking for trouble.
Ask the drive manufacturer about this. Tell him drive cables are not in the picture so he does not try and sell you these cables.

Note: Pumps are variable torque loads and will allow you to reduce the VFD size. In a variable torque application, you generally drop a drive size. So you may only need a 1 HP drive for these 1.5 HP motors.


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