Pool pump
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Take a long lunch now!:thumbup:
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Variable speed is only worth it if there is some good reason to VARY the speed. It only saves money COMPARED to OTHER means of varying the flow from the pump.
That said, sometimes in a pool system design, they use the same pump for running the filter all day that they need for running the sweeper, so the pump is sized for the maximum flow whether or not it needs it all the time. In that case, the variable speed may help save money, but if it is just 2 speeds, so might a 2 speed variable torque motor, and it is simpler.
But then again, it also depends on the type of variable speed pump. Some of the pool pump people are using special permanent magnet motors, which are significantly higher efficiency than traditional motors, but need a special VFD to run them. So those offer savings that offset the losses in the VFD even if run at full speed, but would take years to pay back. The ultimate though is if they are using those motors AND can run at a lower speed, then the savings are dramatic.
That said, sometimes in a pool system design, they use the same pump for running the filter all day that they need for running the sweeper, so the pump is sized for the maximum flow whether or not it needs it all the time. In that case, the variable speed may help save money, but if it is just 2 speeds, so might a 2 speed variable torque motor, and it is simpler.
But then again, it also depends on the type of variable speed pump. Some of the pool pump people are using special permanent magnet motors, which are significantly higher efficiency than traditional motors, but need a special VFD to run them. So those offer savings that offset the losses in the VFD even if run at full speed, but would take years to pay back. The ultimate though is if they are using those motors AND can run at a lower speed, then the savings are dramatic.
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I have my pool pump on a timer to save money.. only run it as much as I need depending on temperature and usage.
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I think all pool pumps are on a timer and used as infrequently as possible to save money. But I have $500 + electric bill 4-5 months of the year. So I'am trying to cut it down some.
When's lunch?
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How much did that gutter cost? I dont work on pools, but I have hooked up one of those "pool j-box". They didn't seem very expensive, but i think they only had room for 2 or 3 conduits.
I thought variable speed motors/pumps were only for 3 phase applications, but i dont know and I'd like to hear the answer to this as well.
I thought variable speed motors/pumps were only for 3 phase applications, but i dont know and I'd like to hear the answer to this as well.
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Do you know how much those pool j-box's cost?
How is a pool junction different from any other 3r junction box?
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Its this funny looking black LB-shaped box, and its got a bonding bar in it.
I don't know what makes it so special, but all the pool companies use them around here. I think its where the pool guys leave the pool light wires, and where the electricians tie into.
Ive only done one of them, and I just did what I was told, so Im not really clear what the deal is.
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Although VFDs for single phase motors do exist, they only work on certain TYPES of single phase motors, and they cost so much that it's rarely worth it. But other than that, you are right, they are mostly for 3 phase motors.
The thing is, a VFD just converts the AC to DC, then makes something that the motor thinks is AC again. In the process of converting the AC to DC in the first place, the VFD doesn't "care" if the AC is single phase or 3 phase, all it does is rectify it to DC anyway. So all VFDs are technically capable of running a 3 phase motor from a single phase source. There are sizing issues to contend with, but most mfrs offer a version, in the 230V realm, that is capable of running a 3 phase motor from a single phase source without de-rating, up to and including 3HP. Above 3HP you have to double the size of the VFD with respect to the motor AMPS (use amps, not HP). There are a few other "gotchas" to watch out for as well, but just ask your supplier, don't ASSume, and you will be OK.
The variable speed motors for pool pumps are used as Jraef said sometimes for the sweep.
I was hooking up a new pool panel and they had one of those UV lights that filters/cleans the water to eliminate or cut way down on chlorine.
I had to call the UV light mfg to ask them some questions about the light.
Anyways, the guy told me the UV lights worked better with the pump running at a slower speed. It gives the UV light more time to clean better.
Then some people run their pumps 24-7. They run the pump on low at night to cut down on noise.
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Are you gonna mount the gutter at least ?
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You would think it needs it, huh? And I will say it's surprisingly sturdy.
When's lunch?
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