# latching relays



## PFNELKAK (Apr 16, 2013)

I'm trying to use a latching relay
to altenate from one 3phase well 
pump to the other. I'm using pressure
switch to energize relay to alternate
pump usage. But all I get is both
pumps coming on. Relay is 2 sets of
no/nc- contacts, 120v ac coil and
120v ac coils on starters. How can
you wire it to alternate pump usage?


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## dronai (Apr 11, 2011)

Use a alternating relay


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## Aydin2011 (Apr 2, 2013)

PFNELKAK said:


> I'm trying to use a latching relay
> to altenate from one 3phase well
> pump to the other. I'm using pressure
> switch to energize relay to alternate
> ...


I hope this is help pls correct me if i am wrong  this is basic latching logic you can change with your own way


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## dronai (Apr 11, 2011)

Doesn't he mean a seal-in maintaining contact, not in logic ?


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## Aydin2011 (Apr 2, 2013)

He can add any relay. Jump wire from contactor coil. I dont know what he has. Hope will work.
Thx


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## wildleg (Apr 12, 2009)

post the relays you are using


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## PFNELKAK (Apr 16, 2013)

*latching relay*

Thanks Dronai- wrong use of a latching
relay. Thanks to other comments but not
using in logic circuit.
thanks all


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## JRaef (Mar 23, 2009)

If by "latching relay" you mean one that has a separate Latch Coil and Unlatch Coil, it is difficult to use those as an alternating relay, the logic is more complicated than you think it is and involves using early-make / late-break contacts on another relay slaved from your pressure switch. It's far far easier to just go get what is called an "alternating relay", one coil, simple logic to use it. The presuure switch closes on the Alt Relay coil, then through the CO contacts to your two motor starter coils. When the pressure switch opens again and takes power off of the alt relay, it changes state (toggles) to be ready to bring on the other pump next time. Furnas used to make the simplest and most reliable one on the market, the Class 47, but when Siemens bought them they sold off that product line to Hubbel Industrial Controls.

http://www.hubbell-icd.com/icd/components/ac5247.asp 

You can download the instruction sheet for a duplex controller wiring diagram on that web page.


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## PFNELKAK (Apr 16, 2013)

*latching relay*

Thanks Jraef. That is the direction I am
going.Appreciate everyones help.
PFNELKAK


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