TRIAC short in Dimming Circuits

[sundar-edaboard]

Dear all,

I am using dimmer circuits designed with TRIAC (BTA16-600B) which is shorted. What could be the reasons. Connected incandescent lamps/LED drivers.

When i replaced the TRIAC the incandecent lamp is flickering.

What is the purpose of choke in dimmer output?

Please suggest.

Regards,
Sundar.A

 

[sundar-edaboard]

The output load is connected through 8A glass fuse serially to the TRIAC. When short circuit occurs the fuse won't blow instead of TRIAC?

https://obrazki.elektroda.pl/4773874700_1416486895.jpg

Please find the attached circuit.
And what is the purpose of choke?

Regards,
Sundar.A

 

[FvM]

If an incandescent lamp burns out, a high short circuit current might flow. Triac dimmers that are not protected by a built-in fuse can be damaged in this situation.

Flickering of incandescent lamp can indicate a defective triac control circuit. LED drivers aren't necessarily suited for dimmer operation.

- - - Updated - - -

That the fuse didn't blow but the triac becomes shorted is a bit unusual. A possible reason might be high continuous current without sufficient triac heatsink, less likely large overvoltage transients (surge).

The choke has mainly the purpose of reducing radio interferences, it also reduces the current slew rate and protects the triac against surge events.