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Simple relay hack - but noise from long cable run

c64

Oct 11, 2018
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I am trying to remotely trigger a gate release, by wiring a relay across the gate release switch. The controlling relay is located downstairs and I have hijacked some of the existing unused house (unshielded multicore bell) cabling, so the cable run is about 15m. I think I am getting a lot of (induced?) noise from the length of the cable run and neighbouring wires, so the gate release triggers intermittently. I guess the solution is to place a 2nd relay inside the intercom, but I wondered if there was a simpler solution? Thanks!

IMG_0496.jpg IMG_0497.jpg
 

Harald Kapp

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Nov 17, 2011
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Wire it this way:
upload_2021-9-3_13-45-24.png
The relay coil is comparatively insensitive to noise on the lines leading to the coil.
 
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Kabelsalat

Jul 5, 2011
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The circuit you've drawn doesn't look correct.
According to that, the switch (missing reference designator) short the relay coil - so that you probably ending up burning the internal circuit.

A relay is not sensitive to normal noise.
 

Harald Kapp

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According to that, the switch (missing reference designator) short the relay coil
The switch/pushbutton seems to be in parallel to the relay contacts, not the coil. It isn't shown where and how the coil is connected.
 

c64

Oct 11, 2018
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Wire it this way:
View attachment 52815
The relay coil is comparatively insensitive to noise on the lines leading to the coil.

The relay is part of an automation system so I cannot move it. But I think you are suggesting the best solution is to use a relay closer to the pushbutton. Many thanks.
 

73's de Edd

Aug 21, 2015
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If this is carrying running power . . .STOOPID SITUATION . . . . . and the ensuing wire resistance then would be of consideration.
Just a thought . . . . . of the resistance of the wires consideration.
I can see an unused :
Black-White twisted pair
Blue-White twisted pair
Brown-White twisted pair

Join the BLACK-BLUE-BROWN to the presently wired in GREEN wire connection.
Join all of the WHITES for the presently wired in White wire connection .
 
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