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Re: contactor/relay question

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  • Dave Mucha
    Hi Phil, Electricaly, the contactors handle the high current to the motors and the switches handle the low power inputs. All you need to do is to replace the
    Message 1 of 10 , Feb 28, 2004
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      Hi Phil,

      Electricaly, the contactors handle the high current to the motors and
      the switches handle the low power inputs.

      All you need to do is to replace the current switches with relays.

      I would use DPDT relays and wire one so that it gets it's power from
      the NC contacts of the other relay. That way, the second cannot
      operate unless the first is closed. The first will break power when
      it changes state.

      Also, if you want to retain manual control, use a switch to control
      the relays.

      Should be pretty straight forward.

      Dave






      --- In Electronics_101@yahoogroups.com, "Phil" <phil1960us@y...>
      wrote:
      > I have a greenhouse that has a motorized ridge vent louver. It
      came
      > with the house when we bought it out of an estate and there is no
      > option to find the installer to get more info on the system.
      >
      > Anyway, I want to control these via a temperature sensor so that
      the
      > louvers open when above a certain temp and close below a certain
      > temp. The logic is pretty simple and I have a proto circuit that
      > does what I want. However, I'm not sure how to control the louvers
      > because...
      >
      > Its currently controlled from a 2 button panel - 1 up, 1 down. The
      > buttons have 115 AC fed into them. These in turn are connected to
      a
      > control panel that has 2 relays and 2 "telemechanic" LC1 D09
      > contactors (and a real rats nest of 16 gauge wires). One contactor
      > is labeled "up", the the other "down". I found the company that
      makes
      > the contactors - Telemecanique. Its a french outfit and through
      some
      > gyrations and guesses, I found the company's site though it doesn't
      > enlighten me much. I believe the buttons drive the relays, the
      > relays drive the contactors which in turn control a 3 phase motor
      > (which is not easily accessable to me).
      >
      > So, I think all I need to do is add 2 relays in parallel with the
      > control buttons and drive them from my control circuit. Does this
      > make sense. Does anyone who understand contactors see any obvious
      > warnings here? Is there a simple drop in module that I could use
      > instead of my home brew solution?
      >
      > An additional question is can I derive power from the 115 VAC used
      to
      > control the existing relay coils? I think I can limit the draw to
      > less than the relay coils need.
      >
      > comments?
    • Phil
      I like that interlock idea. I believe the system already handle simultaneous up/down contacts now becuase when I push both buttons, nothing happens (including
      Message 2 of 10 , Feb 28, 2004
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        I like that interlock idea. I believe the system already handle
        simultaneous up/down contacts now becuase when I push both buttons,
        nothing happens (including nothing bad!).

        I'm still playing with pulling parasitic power from the relay coils'
        115 VAC. otherwise, I'll have locate the controller (and LCD display
        away from the current location (which has no easy source of power
        other than the coil supply). Probably the right thing to do because
        eventually I want to set up communication to be able to determine th
        state of the louvers from my main house or even over the internet.

        --- In Electronics_101@yahoogroups.com, "Dave Mucha"
        <dave_mucha@y...> wrote:
        > Hi Phil,
        >
        > Electricaly, the contactors handle the high current to the motors
        and
        > the switches handle the low power inputs.
        >
        > All you need to do is to replace the current switches with relays.
        >
        > I would use DPDT relays and wire one so that it gets it's power
        from
        > the NC contacts of the other relay. That way, the second cannot
        > operate unless the first is closed. The first will break power
        when
        > it changes state.
        >
        > Also, if you want to retain manual control, use a switch to control
        > the relays.
        >
        > Should be pretty straight forward.
        >
        > Dave
        >
        >
        >
        >
        >
        >
        > --- In Electronics_101@yahoogroups.com, "Phil" <phil1960us@y...>
        > wrote:
        > > I have a greenhouse that has a motorized ridge vent louver. It
        > came
        > > with the house when we bought it out of an estate and there is no
        > > option to find the installer to get more info on the system.
        > >
        > > Anyway, I want to control these via a temperature sensor so that
        > the
        > > louvers open when above a certain temp and close below a certain
        > > temp. The logic is pretty simple and I have a proto circuit that
        > > does what I want. However, I'm not sure how to control the
        louvers
        > > because...
        > >
        > > Its currently controlled from a 2 button panel - 1 up, 1 down.
        The
        > > buttons have 115 AC fed into them. These in turn are connected
        to
        > a
        > > control panel that has 2 relays and 2 "telemechanic" LC1 D09
        > > contactors (and a real rats nest of 16 gauge wires). One
        contactor
        > > is labeled "up", the the other "down". I found the company that
        > makes
        > > the contactors - Telemecanique. Its a french outfit and through
        > some
        > > gyrations and guesses, I found the company's site though it
        doesn't
        > > enlighten me much. I believe the buttons drive the relays, the
        > > relays drive the contactors which in turn control a 3 phase motor
        > > (which is not easily accessable to me).
        > >
        > > So, I think all I need to do is add 2 relays in parallel with the
        > > control buttons and drive them from my control circuit. Does
        this
        > > make sense. Does anyone who understand contactors see any
        obvious
        > > warnings here? Is there a simple drop in module that I could use
        > > instead of my home brew solution?
        > >
        > > An additional question is can I derive power from the 115 VAC
        used
        > to
        > > control the existing relay coils? I think I can limit the draw
        to
        > > less than the relay coils need.
        > >
        > > comments?
      • Kenneth Smith
        ... coils I don t see any reason why you cannot do that. The 120 volt relay should pull anywhere from 24 ma to 45 ma. The relays are then wired like Dave said
        Message 3 of 10 , Feb 28, 2004
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          --- In Electronics_101@yahoogroups.com, "Phil" <phil1960us@y...>
          wrote:
          > I like that interlock idea. I believe the system already handle
          > simultaneous up/down contacts now becuase when I push both buttons,
          > nothing happens (including nothing bad!).
          >
          > I'm still playing with pulling parasitic power from the relay
          coils'

          I don't see any reason why you cannot do that. The 120 volt relay
          should pull anywhere from 24 ma to 45 ma. The relays are then wired
          like Dave said or you would have popped a breaker when you depressed
          both switches because the contactors would have shorted the phases
          together.
          On the interlock switches, I would think that they are there or else
          you could tear up a louver. If you move the louver fully closed or
          open, the motor should stop and you should hear the contactor drop
          out.
          The limit or interlock switches could be built into the gear box.
          One that I worked on, you had to remove a plate to get to it and they
          were two plastic switches, slotted, so you could adjust the stop on
          each end.
          I would use an AC Filter on the pic power supply.

          Ken Smith
        • dangermouse
          Agreed. The systems that I have seen have so many redundant interlocks that it seems silly to some--but that is the nature of industrial control systems. Wire
          Message 4 of 10 , Feb 28, 2004
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            Agreed.

            The systems that I have seen have so many redundant interlocks that it seems
            silly to some--but that is the nature of industrial control systems.

            Wire your contactors so that they cannot both be energized at the same time,
            as someone else has already mentioned. But I've seen systems that also had
            mechanically interlocked switches in addition to these electrical
            interlocks. And others to boot.

            -DM

            ----- Original Message -----
            From: "Kenneth Smith" <kensmith52@...>
            To: <Electronics_101@yahoogroups.com>
            Sent: Saturday, February 28, 2004 6:56 PM
            Subject: [Electronics_101] Re: contactor/relay question


            > --- In Electronics_101@yahoogroups.com, "Phil" <phil1960us@y...>
            > wrote:
            > > I like that interlock idea. I believe the system already handle
            > > simultaneous up/down contacts now becuase when I push both buttons,
            > > nothing happens (including nothing bad!).
            > >
            > > I'm still playing with pulling parasitic power from the relay
            > coils'
            >
            > I don't see any reason why you cannot do that. The 120 volt relay
            > should pull anywhere from 24 ma to 45 ma. The relays are then wired
            > like Dave said or you would have popped a breaker when you depressed
            > both switches because the contactors would have shorted the phases
            > together.
            > On the interlock switches, I would think that they are there or else
            > you could tear up a louver. If you move the louver fully closed or
            > open, the motor should stop and you should hear the contactor drop
            > out.
            > The limit or interlock switches could be built into the gear box.
            > One that I worked on, you had to remove a plate to get to it and they
            > were two plastic switches, slotted, so you could adjust the stop on
            > each end.
            > I would use an AC Filter on the pic power supply.
            >
            > Ken Smith
            >
            >
            >
            >
            >
            >
            >
            > Yahoo! Groups Links
            >
            >
            >
            >
            >
          • Ritesh Waghray
            I am electronic diplomate from India. Please send me the best design of the complete circuitry in image file (scanned). mention all voltages and what motor
            Message 5 of 10 , Feb 29, 2004
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              I am electronic diplomate from India. Please
              send me the best design of the complete circuitry
              in image file (scanned). mention all voltages and
              what motor efficiency U are getting and also answer
              what is the exact problem its NOt at all working.
              There is one way of using Relays with multi options so
              let me see how it can be innervated to to digital temp
              probe or may be a mercury thermometer.

              --- Phil <phil1960us@... > wrote: > I have a
              greenhouse that has a motorized ridge vent
              > louver. It came
              > with the house when we bought it out of an estate
              > and there is no
              > option to find the installer to get more info on the
              > system.
              >
              > Anyway, I want to control these via a temperature
              > sensor so that the
              > louvers open when above a certain temp and close
              > below a certain
              > temp. The logic is pretty simple and I have a proto
              > circuit that
              > does what I want. However, I'm not sure how to
              > control the louvers
              > because...
              > Its currently controlled from a 2 button panel - 1
              > up, 1 down. The
              > buttons have 115 AC fed into them. These in turn
              > are connected to a
              > control panel that has 2 relays and 2 "telemechanic"
              > LC1 D09
              > contactors (and a real rats nest of 16 gauge wires).
              > One contactor
              > is labeled "up", the the other "down". I found the
              > company that makes
              > the contactors - Telemecanique. Its a french outfit
              > and through some
              > gyrations and guesses, I found the company's site
              > though it doesn't
              > enlighten me much. I believe the buttons drive the
              > relays, the
              > relays drive the contactors which in turn control a
              > 3 phase motor
              > (which is not easily accessable to me).
              >
              > So, I think all I need to do is add 2 relays in
              > parallel with the
              > control buttons and drive them from my control
              > circuit. Does this
              > make sense. Does anyone who understand contactors
              > see any obvious
              > warnings here? Is there a simple drop in module
              > that I could use
              > instead of my home brew solution?
              >
              > An additional question is can I derive power from
              > the 115 VAC used to
              > control the existing relay coils? I think I can
              > limit the draw to
              > less than the relay coils need.
              >
              > comments?
              >
              >
              >
              >
              > Yahoo! Groups Links
              >
              >
              > Electronics_101-unsubscribe@yahoogroups.com
              >
              >
              >





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