AC drive Pool pump?

[mltech]

On a high end home it was asked for AC drives for the Pool pumps?
I can get them but why add the expense unless you are going to slow the motor down?
and why would you do that to a pool?
Any input is appreciated.
Thanks
M3

 

[infinity]

Good question. Sounds like a design issue that someone thinks will save money. Who is asking for this?

 

[Jim W in Tampa]

Will it have a water fall ?

 

[mltech]

AC drive

AC drive

A waterfall and fountain like jets shootin up from the walkin shallow area.
This was my thought that they could dial down the speed of the motor rather than limit the amount of water flow?
Is there any advantage to controlling a motor this way, such as electrical savings and or longer motor life?
The GC posed the question. Somebody put a thought in his head?

 

[GeorgeB]

On a high end home it was asked for AC drives for the Pool pumps?
I can get them but why add the expense unless you are going to slow the motor down?
and why would you do that to a pool?
Any input is appreciated.
Thanks
M3

I can think of 2 additional reasons. First, a 3 phase motor can be used on a single phase source. Second, the inrush current (with 3 phase motor) can be limited to a value much less than with across-the-line starting.

With the typical impeller pump (vs. a fixed displacement pump), the practical range of flow control via speed control will be small. My bet is on minimizing inrush.

 

[mltech]

3 phase motor on 1 phase w/o a phase converter?

 

[Jim W in Tampa]

Your dealing with the rich and is no point in figuring them out. Simply give them anything that passes nec that they want.Was taught this over 30 years ago. When dealing with rich don't worry about cost or how long it will take or what you must damage (walls) to do the job. Only time they might back off is if you say it can't be done.

 

[infinity]

3 phase motor on 1 phase w/o a phase converter?

They do make them:

http://web1.automationdirect.com/static/specs/gs1drives.pdf

 

[John Valdes]

The inverter (VFD) can also run the motor at higher than nameplate speeds (base speed). Maybe they want more bang for their buck. I would jump on this job. The VFD pictured above can be easily marked up more than double. Maybe triple the net cost. Add in the labor for installation, materials and programming, you got a pretty good gig.

Reducing speed on a pump will produce some savings. How much I am not sure. Why run it at full speed when you may not have to. You can always slow down or overspeed the motor. Make sure you look at inverter rated motors. They are designed to run slower or faster without harming the motor.

Another thing that can be acomplished is the ability to use the drive to control lighting. Example: Motor on, lights on. There are so many things you can have the inverter do for you.

 

[mltech]

Thanks John
We are definitely doing the job. I am just not to familiar with VFD's and what they can do for me. thanks from south Florida - Go Phins

 

[iwire]

There are so many things you can have the inverter do for you.

Like fail expensively much sooner then a simple old school motor controller would.:grin:

I appreciate all that a VFD can do, in many applications they are just what is needed. On the other hand I see them showing up on things that really do not need them and to use them 'just 'cause they are cool really bothers me. I think it is a disservice to the end user to specify a VFD when a simple motor controller could be used with much more long term durability.

At this point in time if a VFD fails outside of the industrial world most electricians can not troubleshoot or repair VFDs and even once the problem is identified the parts can be expensive. On the other hand a NEMA mag starter is easy to troubleshoot, parts are not expensive and easily purchased. :smile:

 

[mpoulton]

I have a VFD on mine!

I have a VFD on mine!

I am running a 3ph pump (2HP rated) on my pool using a VFD from a 1ph source. It works great! The VFD was about $300, and I have saved more than that in power costs in less than a year. I decided to do it because I wanted serious pump capacity when I needed it, with low power consumption the rest of the time. I can crank it up to 90-100Hz (about 3.5HP to the pump) for super-power vacuuming or backwashing the filter, and then turn it down to 35-40Hz the rest of the time (about 300W to the pump). Also, it's really cool to have a VFD and commercial pump on your swimming pool... Is your client an electrical engineer? That would explain it.

 

[John Valdes]

Like fail expensively much sooner then a simple old school motor controller would.:grin:

I appreciate all that a VFD can do, in many applications they are just what is needed. On the other hand I see them showing up on things that really do not need them and to use them 'just 'cause they are cool really bothers me. I think it is a disservice to the end user to specify a VFD when a simple motor controller could be used with much more long term durability.

At this point in time if a VFD fails outside of the industrial world most electricians can not troubleshoot or repair VFDs and even once the problem is identified the parts can be expensive. On the other hand a NEMA mag starter is easy to troubleshoot, parts are not expensive and easily purchased. :smile:

Bob, I agree with you. I see little need for a VFD in a residential setting. But times are changing. PLC's now operate Christmas lights and are less money than timers and relays. We can run 3 phase motors from single phase power sources for example. Time and money savers to say the least. All the supply houses in my area rep some brand of VFD. Most have some in stock. There is no reason why I could not get one today (July 4th) if I really had to have it. Parts? What parts. We replace smaller VFD's, not repair them.

The point being, if the customer wants it and you can provide it, why not? :wink:

 

[weressl]

On a high end home it was asked for AC drives for the Pool pumps?
I can get them but why add the expense unless you are going to slow the motor down?
and why would you do that to a pool?
Any input is appreciated.
Thanks
M3

There could be many reasons to do that, some of which was already posted.
Another one I can think of is to maintain a constant pressure when(and if) various users are turned on an off, like jets or washers or just simply maintaining constant flow as the filter slowly gets filled with debris and reduces the flow.
There are two kinds of 'rich' people. One is the lucky one, and one is the smart one. The lucky ones are seldom maintain their riches, so I would install it to help advance their demise....:smile: The smart ones have their money because they know how to spend it where it multiplies and returns more money, so I would install it for them as their further increasing wealth would produce more work for me in the future:grin:

 

[Jim W in Tampa]

Many of the rich in Fl are only rich till the next drug bust. Make sure where your money is coming from.

 

[chris kennedy]

Many of the rich in Fl are only rich till the next drug bust. Make sure where your money is coming from.

Jim, you have to let go of the 80's.

 

[mltech]

very cool

very cool

They do make them:

http://web1.automationdirect.com/static/specs/gs1drives.pdf

Thanks for all the good info. I was looking for a little education on the subject and I believe I got it. By the way Automation direct is probably one of the best websites I have ever used. Just purchased 3 controllers and can't wait to tie them to Lutron Homeworks...
Thanks for all your input.
M3