To Create Normally Closed Contact with Electronic components.

[helex]

Hello Everyone,

I need to design a "Normally Closed" (NC) contact with Electronics components with following load requirements,

Load Voltage = 230 VAC
Load Current = 2 A Max.
Load = AC Motor

please suggest any low cost solution for the same.

 

[KlausST]

Hi,

You don't tell anything about the control signal.

I'd use a NO relay, but invert the control signal.

Klaus

 

[helex]

Hi Klaus,

Thanks for your reply.
Please note that control signal coming from TRIAC, SCR and Microcontroller network.
I don't want to use mechanical relay.
My requirement is that if control circuitry fails because of any reason then my Fan should be kept ON through "Normally Closed" contact.

 

[KlausST]

Hi,

I didn't mention a mechanical relay.
I said NC, but I assume this can't fullfil the requirement "when control circuit fails"....

Does "fail" always mean "false OFF" ... isn't "false ON" possible, too?

Klaus

 

[helex]

Fail means both "false OFF" and "false ON".
Any component of Control Circuit may be "Short" OR "Open" during failure.

 

[KlausST]

Hi,

in this case you can´t rely on the control signal. Thus even a NC relay won´t help.

I recommend a second (redundant) control signal. Best if it is from another independent circuit with indpendent source of information.

Klaus