Best and easiest way to identify a tripping over temp switch
Best and easiest way to identify a tripping over temp switch
(OP)
I have two NC over temp switch in a circuit and they are connected in series one after the other.
Each is connected to a different side of the compressor and they are suposed to open when the compressor is over heating.
One of these switches keeps tripping out the compressor almost 5 times a day.
I want to add a mini circuit to the current 24DC one that alerts will alerts me the side of the compressor with a problem so that has a problem.
Each is connected to a different side of the compressor and they are suposed to open when the compressor is over heating.
One of these switches keeps tripping out the compressor almost 5 times a day.
I want to add a mini circuit to the current 24DC one that alerts will alerts me the side of the compressor with a problem so that has a problem.





RE: Best and easiest way to identify a tripping over temp switch
I'd eliminate that possibility before adding complexity.
Mike Halloran
Pembroke Pines, FL, USA
RE: Best and easiest way to identify a tripping over temp switch
If these feed into something like an opto22 input in the existing control, the current will be fairly small. Any sensing across the two switches (like another opto22)would draw enough current so that existing controller would never see the open switch.
The work around this would be to put a 200 ohm resistor on the existing controller input to provide a greater load. Then sensors across the switches would likely work.
RE: Best and easiest way to identify a tripping over temp switch
RE: Best and easiest way to identify a tripping over temp switch
If this is a PLC-based controller and you have a spare input you can do the same in ladder logic.
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If we learn from our mistakes I'm getting a great education!
RE: Best and easiest way to identify a tripping over temp switch
TTFN

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RE: Best and easiest way to identify a tripping over temp switch
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RE: Best and easiest way to identify a tripping over temp switch
Or, an appropriate micro-fuse can be chosen. But not as colorful as the Blue Dot solution.
Good on ya,
Goober Dave
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RE: Best and easiest way to identify a tripping over temp switch
I was thinking that since the TEMP switch is NC, I can use the NO contact for the LED circuit. I'll use the resistor to limit the current in the LED circuit to about 1A & I expect the red LED to light up and stay so every time the TEMP switch trips.
I'm not sure if this would work but I'll be testing it out soon.
RE: Best and easiest way to identify a tripping over temp switch
TTFN

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RE: Best and easiest way to identify a tripping over temp switch
RE: Best and easiest way to identify a tripping over temp switch
RE: Best and easiest way to identify a tripping over temp switch
Mike Halloran
Pembroke Pines, FL, USA
RE: Best and easiest way to identify a tripping over temp switch
I understand I would have to use some ladder logic circuit. I'm just not quite sure how to monitor a single NC contact that blows open shuting off the compressor & waiting for a manual reset.
RE: Best and easiest way to identify a tripping over temp switch
RE: Best and easiest way to identify a tripping over temp switch
Google how a three-wire motor starter works, one with a start button and a stop button. You would basically build a miniature version of it using a relay rather than a contactor.
The temp switch is the 'stop' button, the 'arm' or 'reset' contact is the 'start' button. Use one of the relay contacts to replace the temp switch in the circuit. Obviously you will need a source of power for your relay.
When the switch opens the relay drops out and causes the machine to trip as it does now. The scheme requires a manual reset so you have a latched indicator of which switch caused the fault which will sit there until you reset it. No need to sit for hours waiting for a trip.
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If we learn from our mistakes I'm getting a great education!
RE: Best and easiest way to identify a tripping over temp switch
Are you saying I must do something like this?
-----------NO------temp switch(NC)--------coil--------
|
|
-------reset----|
--------------------NC--------buzzer------------------
|
|
|----lamp--------------------
RE: Best and easiest way to identify a tripping over temp switch
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If we learn from our mistakes I'm getting a great education!