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Re: Variable speed wall clock

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  • Dave Mucha
    ... http://www.mpja.com/category/MPJA_Kits/UNIPOLAR_STEPMOTOR_DRIVER_KIT_8479_KT.asp ... I have heard good reports for that driver. it is full step, but for a
    Message 1 of 31 , Aug 2, 2005
      --- In Electronics_101@yahoogroups.com, "grantfair2001"
      <grant.fair@s...> wrote:
      > At $15.95 this is the cheapest kit solution for a variable speed
      > unipolar stepper controller I know of:
      >
      >
      http://www.mpja.com/category/MPJA_Kits/UNIPOLAR_STEPMOTOR_DRIVER_KIT_8479_KT.asp
      >
      > Speed may be varied by an on board pot, or by externally applied
      > pulses. In addition to the kit it does need two separate power
      > supplies, one for the controller and one for the stepper.
      >
      > Grant


      I have heard good reports for that driver. it is full step, but for a
      clock, that should be fine.

      It is also available for $13.95
      http://store.qkits.com/moreinfo.cfm/QK179

      I'm not sure if it would be easier to make a clock movement or to add
      onto one. the gearing would be 12:1 no ?

      Dave





      >
      > --- In Electronics_101@yahoogroups.com, "mcgyver42y" <mcgyver42@c...>
      > wrote:
      > > I have the need to create a prop for a theatrical production. This
      > > prop is a large wall clock that must run at variable faster-than-
      > > normal speeds. The speed should be controllable remotely by the
      > > lighting operator, and should be variable from 1 to 4 times normal
      > > speed.
    • Chris Wardell
      I d just try running some bell wire from the clock to the control circuit. C.W. ... grounded ... coil ... discharged. ... through
      Message 31 of 31 , Aug 4, 2005
        I'd just try running some bell wire from the clock to the control
        circuit.

        C.W.

        --- In Electronics_101@yahoogroups.com, "Dave Mucha"
        <dave_mucha@y...> wrote:
        > --- In Electronics_101@yahoogroups.com, "Chris Wardell"
        > <ctwardell@w...> wrote:
        > > Dave,
        > >
        > > The cap is how the positive and negative pulses are achieved.
        > >
        > > When OUT (of the 555) is low, the cap is discharged because the
        > > positive lead is at (near) ground and the negative lead is
        grounded
        > > via the coil. When OUT goes high, the coil momentarily sees Vcc
        > > while the cap is being charged. When OUT drops low again the
        coil
        > > sees -Vcc because the positive lead of the cap is now at ground
        > > driving the negative lead below ground while the cap is
        discharged.
        > > The cycle then repeats...
        > >
        > > This also results in a slow decay across the coil, so no diodes
        > > needed.
        > >
        > > The biggest issue is sizing capacitor so enough energy flows
        through
        > > the coil during charge/discharge to move the actuator.
        > >
        > > C.W.
        >
        > I missed that part of the control sequence.
        >
        > my bad.
        >
        > What to do to handle the 150 foot run ?
        >
        >
        > Dave
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