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Circuit for pool pump — Parallax Forums

Circuit for pool pump

bboy8012bboy8012 Posts: 153
edited 2011-06-20 14:34 in Propeller 1
I am trying to see what compnent I would need for a 240V pool pump, to control it? I have been searching and came across a 24V relay would that do. My ultimate goal is to just get the pump to turn on and off remotely from a webrowser. Thanks

Comments

  • Cluso99Cluso99 Posts: 18,069
    edited 2011-06-17 15:42
    Years ago I built a circuit using a single component that was an optoisolator and Triac combined exactly for this purpose. But be careful of the 240V - it is much more lethal that the 110V. You should aim to have 7KV isolation and 0.3" space between components on each side. A 1mm slot is also preferrable.

    Otherwise, a relay would do fine, using a driver of course, and the relevant isolation between circuits.
  • LeonLeon Posts: 7,620
    edited 2011-06-17 15:42
    You really need something that can be controlled by a logic output. What is the rating of the pump motor?
  • bboy8012bboy8012 Posts: 153
    edited 2011-06-17 17:15
    This is whats on the pump 11.0-10.2/20.4. So Im taking it as its 10-11 amps with a peak of 20?
  • Desy2820Desy2820 Posts: 138
    edited 2011-06-17 18:10
    I'd suggest a contactor. These are most commonly used for outside A/C units to control the compressor. (Contactor is basically a specialized relay for motors.) This type is controlled by 24 volts DC at a few mA to the coil and can handle a 240 volt motor at up to 30 amps. Something like this: http://www.myhvacparts.com/Catalogue/Air%20Conditioning/Contactor%20Order.htm You'll want a two-pole contactor.
    (Note: Not a site recommendation, just an example)

    With a relay (or contactor--relay for motors), you have two different voltage ratings. One will be for the coil, the other the contacts or load. The contacts will also have a current rating. You do want to oversize the contact's current for the load to be controlled. Relays are also designed differently when handling an inductive (motors) versus a resistive (lights, heating elements) load. Coil amperage is not always specified, so you may need to measure or calculate it.

    With 220V, you MUST switch BOTH supply legs on or off TOGETHER. Do NOT buy anything intended for 110V, as it is only designed to switch the one leg.

    Finally, use EXTREME caution. 110V is nothing to sneeze at, and 220V ups the ante. If you are at all unsure what you are doing, DO NOT PROCEED. Since this is a pool, electrocution is a very REAL possibility. Electrical codes are very detailed on both pools and hot tubs for this reason. Do not alter the grounds or bonds in any way, shape, or form.

    Finally, I'm not an expert, but I would guess your motor can be wired to run from 110V or 220V. So the 11 amps is probably the 220V starting current, with 10 amps running. (Motors usually draw maximum current when starting.) 20 Amps would be while running on 110V. I don't recommend trying to rewire this setup for 110V, leave it at/on 220V.

    How is this currently turned on and off? I would guess that there is a timer of some sort, even if mechanical. It might be simpler to override the timer with your web system instead of trying to directly control the motor—and possibly a little safer. Try to find the owners/installers manual for the timer, if you don’t already have it.

    Finally, I cannot stress this enough, SAFETY, SAFETY, SAFETY……and did I mention safety?
  • bboy8012bboy8012 Posts: 153
    edited 2011-06-17 18:39
    Thanks desy2820 for the info. My ultimate goal is to make a timer/controller, since my current one is just a little clock wheel.
  • EGMonoEGMono Posts: 31
    edited 2011-06-17 18:57
    I've never played with the kind of high-power circuit you're looking for, but they do make solid state relays for high power applications. I found some examples here: http://www.controlanything.com/Relay/Relay/AC_SSR
  • Desy2820Desy2820 Posts: 138
    edited 2011-06-17 19:40
    Actually, I had a random thought--someone must already make automation systems for pools. I was hoping to find a reasonably priced timer with a wireless override feature. What I’ve found is a wireless receiver that looks like it can directly control the pump--nothing extra needed. What I can’t find is information on the wireless signal, it may be proprietary. You may just want to hack the transmitter instead.

    The basic idea is that your web application/device uses the hacked transmitter to send the correct wireless signal, turning on the pump. This may/may not work, depending on many things, such as your home’s construction or distance between transmitter/receiver.

    Reciever: http://www.smarthome.com/42664/Intermatic-RC613R-Wireless-Modular-Radio-Receiver/p.aspx Click on the image, and read the text on the transmitter.

    Transmitter: http://www.smarthome.com/42663/Intermatic-RC939-Three-Channel-Handheld-Radio-Wireless-Transmitter/p.aspx

    I hope this helped, or at least gave you some food for thought.
  • pacmanpacman Posts: 327
    edited 2011-06-17 19:59
    Desy2820 has the right idea.

    A contactor is basically a 3pole relay (I have worked with 4 pole contactors). Buy a normal 3 phase contactor (but only use two poles) and pull it in with a low voltage coil run from the prop (prop pin drives transistor, transistor switches conatcor coil, etc, etc).

    Contactor coils come in MANY different voltages - but be aware that a 24VDC coil in a contactor will pull a reasonable amount of current when on.

    Yes SAFETY is a VERY BIG concern. Please take EXTRA care when woking with anything above 24V. DO NOT work on a 240V circuit live - Turn it OFF AND UNPLUG it before you touch ANYTHING in the 240V world
  • tonyp12tonyp12 Posts: 1,951
    edited 2011-06-17 20:36
    OP did not say where in the world he is.

    Is the pump hooked up to 1phase and neautral, or two 120v phases?
    http://users.telenet.be/worldstandards/electricity.htm#voltage

    A pool pump should be running 6-8hrs a day during daytime everyday,
    so I could not see the need to turn it on/off from a website?
  • bboy8012bboy8012 Posts: 153
    edited 2011-06-19 15:47
    Im in El Paso, TX, my spa contoller died, and I figured why not see if I can control it from a webpage, or wirelessly
  • tonyp12tonyp12 Posts: 1,951
    edited 2011-06-19 16:57
    Spa or pool, two speed or single speed?

    Spa pumps sometimes are two speed,
    slow speed from a timer once a day for an hour or so to keep it clean.


    Here is a generic pool pump timer:
    http://cgi.ebay.com/INTERMATIC-T104-72-TIMER-POOL-PUMP-T104M-220V-40-AMP-/280688121675?pt=LH_DefaultDomain_0&hash=item415a50d74b

    On the other hand if you want to turn on the Spa and it's Heater 2 hours
    before you plan to use it from a webpage, that is somehing I also could use.
  • bboy8012bboy8012 Posts: 153
    edited 2011-06-20 14:22
    Ultimately thats what I want to do, I just have to gain the knowledge and what components I need.
  • tonyp12tonyp12 Posts: 1,951
    edited 2011-06-20 14:34
    If the distance is not to long, you could use the Parallax Spinneret as the brain.
    You would get web interface to turn on relays etc.

    Just hook it up the household router, set the router to forward port 80 (or 8080) to the Spinneret.
    If your IP change often, use the routers dyndns.org function.

    Or other option is to use a Wifly RN-174 (wifi, with some basic GPIO ports that can be used to flip relays)
    Not sure how easy it will be to toggle a pin from a webpage, I know it can be done through telnet though
    http://www.mouser.com/ProductDetail/Roving-Networks/RN-174/?qs=Ad2LRJtGXDvZiwodqCQgvA%3d%3d

    But the 240v with massive amps for both pump and heater, you will need to be careful how you design
    the relay board.
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