120v Relay Flickering chattering on and off very quickly ?!

Discussion in 'The Projects Forum' started by shawn-, Mar 6, 2013.

  1. shawn-

    Thread Starter New Member

    Mar 6, 2013
    the module that i modified originaly is very simple , you plug the module in youre 120v wall plug , and the other end of the module is a house 120v plug but its controled by a rj11 wire and is connected to the main module thats a climate controler

    now the module that i want to modify is quite simple

    perfectly normal operation of the module

    120v going in , rj11 gives signal , 120v is now comming out of the module
    120v goin in , rj11 gives no signal , 120v is not comming out

    now my project witch is finished at 99% and looks wicked [​IMG] well .. its not working well !

    my project , take the 120v output of the module , and plug it to the heavy duty;s 120v voice coil

    very simple , now in theory when the module receives the rj11 signal, 120v comes out of the module , the 120v now goes though the heavy duty relay turning it on and now i can plug what ever i want on the heavy duty relay like a 240v heater ! ( that was the hole ideal [​IMG]

    everything is working as planned except when the heavy duty relay gets a signal it doesnt get a steady signal it gets a pulsing signal making it turning on and off veryy quicky ( if i plug my module like this its a fire hazard ..... my relay will end up taking fire because of high current 240v 6a , it will melt the 2 contact point in 2 min like this ... )

    there must be a resistor or a capasitor i can put on the line and make it steady again ?

    it must be a safe solution because example if its only a matter of a resistor to be added to the heavy duty relay's voice coil and then without me knowing burns and the relay flicker's again then its not good at all ... i rather have a system that if something like the resistor burns then the signal cannot be closed looped then the relay will never open

    if i plug the relay direcly on the houses 120v it works perfectly , some how the module transfers the currents slighly alternative to extremely alternative ?

    all this just to ask how to make my heavy duty relay work constant grab and not going on and off

    btw this module is made and designed to be used as a heater controler

    you put a 10amp or less 120v heater and it will control the room..... i wanted to put my high power relay to control my 240v heater....

    if i plug a light bulb at the end of the module it will light up

    my relay acts exactly like a jewelers engraver , turns on and off like 30-60 times a second like hz ?

    lets take the Second picture

    the bottom connecting ,

    first on the left white 120v in ,
    second middle black 120v in

    third on the right black 120v out
    fourth top black 120v out

    third & fourth is the + & - 120v of the Heavy duty relay ( take the same + & - instead of pluging the relay plug a 120v light and it works perfectly .. )

    the 2 bottom round hole of the box is the the 240v in & out

    this is the original ( 5e picture ) module no modification ( this module simply plugs in youre house 120v plug & you plug in you're 120v heater )

    i just took the 120v output and pluged it in my relay , and aks up , if i plug my relay in the 120v directly no problem...

    and here is the module's ( 6e picture ) relay up close

    top left black wire 120 v out to heavy duty relay's voice coil
    bottom black wire 120v out to heavy duty relay's voice coil

    top right black 120v in from house
    top right white 120v in from house

    hope there is a solution for this pulsing 120v ...

    hope someone can help :)
    Last edited: Mar 6, 2013
  2. shawn-

    Thread Starter New Member

    Mar 6, 2013

    Last edited: Mar 6, 2013
  3. shawn-

    Thread Starter New Member

    Mar 6, 2013
  4. tracecom

    AAC Fanatic!

    Apr 16, 2010
    I don't really follow what you are trying to do. However, a chattering relay often indicates that it is being powered by AC when it was designed to be powered by DC. I also notice that the relay that is mounted inside the box on the green PCB is marked 110 VDC. If that relay is being powered by AC, it may chatter.
  5. JohnInTX


    Jun 26, 2012
    As tracecom says, you seem to be driving a DC relay with AC and it will chatter like crazy. It might be that you have a blown bridge (BR1?) and are driving the DC coil 1/2 wave or that the DC relay is misapplied. You have a couple of options:

    Replace the relay with one that has an AC coil. The relay shown is a standard T90 class and they are available with a 120VAC coil.

    On the PCB, I noticed the SMT marked BR1. Is this a bridge rectifier that rectifies AC to drive the DC coil? If so, sounds like its toast. If one leg is blown open, you'll get 60hz chatter due to the 1/2 wave drive.

    The other devices, RL2 and RL4 look like inline bridge rectifiers as well. The DC(-) leg of RL2 looks like its connected to one of the coil terminals of the unstuffed relay. Perhaps the square (+)terminal is connected to the other one? If so, maybe they are indeed meant to fullwave rectify the AC to drive a DC coil. In this case, is RL4 the bridge rectifier with a blown leg? The 1/2 wave result would also account for the chatter.

    Whichever it turns out to be, you should consider the high voltage spike (probably in the 400-600V range) that occurs when a T90 coil is opened. If you are driving with a bridge, the bridge must be able to handle it. I use 1KV bridges in these applications. Alternately, you could use a suppression diode across the coil (DC only!) or a MOV to clip the surge.

    Let us know what you find.
    Have fun!
    Last edited: Mar 7, 2013
  6. shawn-

    Thread Starter New Member

    Mar 6, 2013
    i found the solution ! it was very simple !

    the big heavy duty relay was bolted to close back and blocking the voice coil plate....

    simply bent the metal a little and it works perrrrrfectly !!! :)))

    akward situation hun ? .... lurned it the hard way i guess !

    thanks !