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Help me find an upgrade to a relay

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  • 15-11-2014 10:52am
    #1
    corglass
    Registered Users Posts: 1,113 ✭✭✭


    Hey guys,

    I just repaired a failed dry joint on the control board of my dishwasher. The joint failure is a common issue and is a result of an AJS1311 relay getting too hot. The relay controls the heating element within the machine and over time the contact within the unit fails due to the high current it's handling.

    Can someone recommend a replacement unit based on the attached specifications?

    Thanks a mill

    Screenshot_2014_11_15_09_48_01.png


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    #2
    Tibulus
    Registered Users Posts: 203 ✭✭Tibulus


    I would talk to TCM controls in Harolds Cross. These guys have gotten me out of a few sctatches.


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    #3
    brightspark
    Registered Users Posts: 2,637 ✭✭✭brightspark


    How about leaving the existing relay in place and use it to turn on an external relay instead of directly powering the element?


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    #4
    corglass
    Registered Users Posts: 1,113 ✭✭✭corglass


    brightspark wrote: »
    How about leaving the existing relay in place and use it to turn on an external relay instead of directly powering the element?

    The existing relay doesn't handle the full load presently, it's only switching 12v at 10 a max so I suspect there's a larger DC to AC relay next to the heater deeper in the machine.

    The existing relay is clearly shot and the soldered joint will no doubt fail again shortly.

    I was hoping to use a replacement 12v relay with the same footprint but rated for 15 or 20A.
    My difficulty is trying to find a suitable one


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    #5
    Diggerdunne
    Registered Users Posts: 431 ✭✭Diggerdunne


    Defo try Tcm controls in harolds cross. Mick in there is very helpful. He will no doubt come up with something for ya...


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    #6
    DublinDilbert
    Registered Users Posts: 5,380 ✭✭✭DublinDilbert


    I would pick up a large relay, even from the likes of maplin. Then just wire from the relay onto the PCB with wire suitable to handle the current. You could even glue the new relay to the PCB.


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    #7
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    DublinDilbert wrote: »
    I would pick up a large relay...Then just wire from the relay onto the PCB with wire suitable to handle the current.

    +1

    Relay's are commonly under-rated. I double the relay size per application. I'm using 30A/50A relays (continuous/intermittent) for 15A-20A loads continuous and they still get hot after an hour.


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    #8
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Sir Liamalot wrote: »
    +1

    Relay's are commonly under-rated. I double the relay size per application. I'm using 30A/50A relays (continuous/intermittent) for 15A-20A loads continuous and they still get hot after an hour.

    Its probably the winding that gets warm as much as anything else, so even an unloaded relay will heat up when the coil is energised.


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    #9
    [Deleted User]
    Posts: 5,238 ✭✭✭ [Deleted User]


    Yup usually it's the coil that fails not the contactor. You can make it really complicated and get them to make at full power and then PWM it to hold. Works for DC coils dunno about AC.


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