Electronics > Power/Renewable Energy/EV's

Phase Dimmer Control using Triac

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dinesh4761:
Hello Sir/Madam,

I am engineering student making phase dimmer control using triac
The schematic is as attached
What I have observed that many times attached circuit stop working due to failure of triac
I am not sure is it because of di/dt or dv/dt failure. In order to avoid this I have used triac of much higher rating (10A) even though current needed can be as low as 1A.
However the problem continues.

I have observed that the failure is for transformer powered halogen lamp (inductive load?) and for ceiling fans.
It works satisfactorily for incandescent lamps.

Also I am sharing one more observation that if I connect glass tube fuse link in series with the load then the fuse blows.
From the various information available I realized that I need to use choke / inductor to overcome this problem. Is that right?
I need help to
    1. To find out the value of the inductor for 0.5A, 1A and 2A
    2. Is this a special type of inductor? if yeswish to know make

Thank you in advance

Dinesh

Kartman:
The choke (inductor) limits the rise of current which is highest at 90deg turn on. You want a core material that is lossy with high frequencies, like the Amidon yellow/white material. The actual inductance required depends on your current. Usually 200uH upwards. There’s plenty of info on the web to determine your inductance and selection of core size/wire size/current etc.

Using phase control for motors is tricky - due to the inductance the current zero crossing is different to the voltage zero crossing so you need to adjust your on  and  off timing carefully.

Circlotron:
What could be happening is if the conduction time of positive and negative half cycle are not exactly equal there will be some DC current flowing in the load. With a transformer or motor load they can easily saturate with the DC and then pull a much larger than expected current. This imbalance will not affect an ordinary light globe.

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