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Author Topic: switch for a bilge pump  (Read 7462 times)

malcolmfrary

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Re: switch for a bilge pump
« Reply #25 on: July 28, 2010, 10:08:32 AM »

Nice one PMK, very neat.
Why the high/low level detectors?

The idea was that the pump should not operate until there was enough level to ensure that the pump would prime, and would run until the level was too low to ensure water in the pump since pumps that can handle a serious influx of water often don't like running dry as Landlocked has noted.
PMK, that over-ride.  I assume that it could be wired into a switcher?  My choice of output transistor would have been a TIP14sommatorother, because they are easily available,  pretty much bullet-proof and I can still understand how they work.
I did work out another version using a CD4001,same number of components, a bit cheaper and would have worked to lower voltages.  The quad bi-lateral switch gets a bit marginal in this application on low voltages.  If only I could remember where I hid it......
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PMK

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Re: switch for a bilge pump
« Reply #26 on: July 28, 2010, 10:18:08 AM »

"I assume that it could be wired into a switcher?"

Ha, I see where you're going with that. Nice one!
A switcher would work for sure, but since the over-ride is tied to the pos. rail, would probably be easiest to do it via a relay?
When initially playing with your ckt on the protoboard, a TIP122 was also good for several amps.
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FullLeatherJacket

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Re: switch for a bilge pump
« Reply #27 on: July 28, 2010, 03:02:49 PM »

would probably be easiest to do it via a relay?
What? You mean like a relay switcher? Think "P43"................... 8)
In testing this circuit works better on 12v than 6v, and the Darlington transistor seems to perform marginally better than a standard MOSFET eg NDP6060L. All power to Doc and PMK for their collective effort. BTW the three-level sensor arrangement is also to prevent the pump from cycling on and off as the model rolls/pitches or when the water level is just on the cut-out point.
One day I'll find time to get this beggar into the catalogue, as our Aussie agent has mentioned it more than once, too.
"So much to do; so little solder........."
FLJ
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Shipmate60

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wombat

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Re: switch for a bilge pump
« Reply #29 on: August 01, 2010, 12:34:16 PM »

Thank you PMK for the circuit.

Do you or anyone else, know where to obtain Q2 - NDP6060L or know of an equivalent?

Can't find it with Radiospares and Farnell say no longer stocked.

Thanks,
Mike

Try Farnell order codes 101-7725 or 101-7726

Wom
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