Any way to protect TRIAC from exploding when over current?

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Nicholas

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protect triac

if output overcurrent or even short circuit, the TRIAC would got blown up at once after triggering. any way to avoid this? under resistive or inductive load conditions. Thanks
 

what causes triac to short

Using fast blow fuse.
 

triac fuses

8) FAST blow fuses may not protect, there is a class called "Semiconductor Fuse" which blows at a specific I2T rating.
 

protect triac from over current

what if I need to monitor the current and safely turn off the TRIAC when needed before it burnout?
 

triac circuit

As much as I know, high current semiconductor fuse is more expensive than triac itself. Hence, I don't see good reasons for its use.

I don't understand how do you mean to "safely turn off the TRIAC when needed before it burnout". With another high power fast switch that can withstand short circuit current?

maranaza
 

overcurrent triac

Please provide more information: Triac type, load type, nominal load, etc.

Triac's generally can tolerate 20 times overload for one (1) 60Hz full wave cycle.

Fractional phase conduction has even higher overload tolerance (easily exceeding 100 times for small angle conduction cycle).

You can protect your triac and other circuit elements by senseing the overcurrent (using low resistance shunt) and locking out the triac triggering circuit.

A fault indicator and some fauilt reset protocol (time wait, reset button, power removal, etc.) would be nice too

General circuit usage details :
https://www.epanorama.net/circuits/semiconductor_relays.html#overcurrent
 

protecting a triac

oh, I misunderstood that when overload or short circuit, the TRIAC will go to hell in a very short time before I can do anything to rescue it. Now, I think I can do some detecting job before trigger the TRIAC to avoid short circuit. And for overload, just keep sensing the current all the time.
 

how to protect triac with fuse

:wink: Once a Triac is turned on you have to remove power in DC application or with AC wait for the Zero crossing before u can switch the triac off.
If the cost of the Semiconductor FUSE is not acceptable U can pretty well change the normal fuse and the triac. u can make a pluggable assembly of triac and normal fuse which can be replaced easily.
 

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