Need a Variable Frequency Controller

Some interesting stuff turned up on this Web page:
https://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4ACEW_enUS495US408&q=web+enabled+vfd

whet what

son't don't

Sorry PW, I try again to answer but I cannot get it on the forum.

There are 3 filters, a chlorination system, a fountain, a spa, a solar system and a heat pump. All have different requirements and pipe diameters. We use an automated system from Jandy with 4 2 way valves. Jandy doesn't handle 3 phase stuff. So the VFC will be controlled with an appendix program, that gets info from outside thermometer and various sensors in the appropriate circuit lines.

Just to name one: back flushing the filters at to high flow rate spews the sand out.

Rgds. D

Backwashing a sand filter without spewing the sand out is as easy as installing a partially-opened valve in the backwash drain line, and taking the handle off following commissioning. It doesn't need a variable frequency drive.

At least, that's the way most others do it.

VFDs do indeed save energy in centrifugal pump systems, but to PWSlacks point, they don't save energy just by being there, they save energy by REPLACING another less efficient means of VARYING the flow rate. So if your flow rate is not varying, then he is correct, there is no potential for energy savings.

If however the REASON why he has 3 pumps for one pool, is a means to get different flow rates, THEN there may be an opportunity here to save some energy by going with one larger pump and varying the speed, which reduces the losses inherent in the other two pumps.

But without knowing all of the details about what you have and what the system needs to accomplish, there is no way to predict in advance that this idea has merit. This is far too complex to deal with over a forum like this, you need a pool system specialist to look at it.

To the issue of remotely controlling the VFD via a WiFi system, it is possible, but not practical. There are VFDs out there that have built-in Ethernet communications ports, but the PC system would need industrial control software to make it work and wireless Ethernet routers, etc. etc., it would be incredibly cheaper to just run a couple of wires to it.

Well said. The original poster has given no indications as to why a varying flow is needed.

Too many Electrical Engineers and not enough Process Engineers! The process comes first. Electrical engineering is secondary.

what you need to look at are VSD's ( variable speed controllers) they also have a large selection of add ons - one company worth looking at is schneider electric they are world wide - the US voltages are not a problem , and the add on's will have a wifi package. As for power usage - Solar is a daytime option use a sunny boy tripower after you have worked out your start currents etc hint-start the pumps separately this will reduce your start current and your inverter - if you need power at night use a hybrid system with batteries to provide short runs at night . regards RobM

The solar is used during the day. It is a water pipe system on the roof under the sun. This variation as said is coupled to the outlet temperature of the solar with temp sensor.

As soon as this temperature is too low and there is a demand for warm(er) water, the heat pump will engage. This has all been programmed already. The only thing is the VFD that needs to adapt the flows.

Solar has 2" piping, jets 1 1/4", heat pump max 1 1/2". Manifolds 3" etc...

Thanks for your input.

Try arduino, it has wifi, and you can let it control things like vfc through I/O ports

example link example link

And there's a lot of another industrial types of pc out there. Example

or you can make this adorable robot... http://www.youtube.com/watch?feature=player_embedded&v=Raqyhsj_zFo#at=16

dvmdsc,

Many years ago I was the builder for a homeowners' association pool, with 3 filters and one 5Hp pump. Much later, when that pump and motor had died, I redesigned the inlet piping to use three 1.5Hp pumps, so the flow rate could be reduced at night by shutting off two pumps (this still kept the filtration rate within code requirements for off-hours). However, the oversized piping put into the original construction caused the pumps to be way off their curves. Through trial and error we settled on significantly oversized (3Hp) impellers turned back down to be within the HP capacity of the motors while having large enough cross-sections within the impellers to avoid cavitation at the very low back pressures of running a single pump. We never did put in the automatic controls I had hoped to add, however.

In your system, I suggest that you list carefully the required flow through the various parts and the pressures required in each part to achieve this flow. Once you know the flow rates and pressures you can then work on the pump and motor. For the controls, many industrial VFD's (variable-frequency drives) are made with single-phase input and three-phase output, so this should not be any problem. Schneider, ABB, AB, and many others will probably all work (using a single-phase input will require a drive sized larger than if a three-phase input were used). You can connect an analog input from a pressure transducer or from a flow transmitter to give you speed control. Then add (if needed) interfacing relays to one or more digital (discrete) inputs on the drive to tell it which pre-programmed value it is to use for its speed. With this approach, you can match output to the needs you have. You can also program it for reduced flow at night, etc. etc. etc.

Wireless transmitter systems that control these relays would be another component, but again many manufacturers are available.

This is not a rocket-science problem, so I don't see any difficulty in making it all work. Just take steps slow and carefully. Read the manuals; ask more questions when you have done this and still can't get it to work correctly. Beware of experts who know their field very well but often don't have the breadth of experience to apply it into a non-traditional or non-standard way.

-John M.