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Why do we get a humming noise when we controll ceiling fan through a triac. I have made a remote controled circuit for controlling light and fan. Used the above zerocrossing method. When the fan is on full speed there is no noise but when i reduce the fan speed the noise is prominent at low speed the fan makes noise. I guess it is due to the reason that the fan gets 220v form mains and when i reduce the speed there is less current flowing through the Triacs. I don't know the exact reason of the humming noise but im sure there is no problem with the fan :-P what can ne the possible reason behind it and what is the solution. Thanks
And thnks bloke, you've been very helpful
Il definitely check my pcb as you said.. Do you have 110v ac or 220v ac.. At my place i have 220v. Does that matter.. How come your resistors do not get hot at all even if you use 1/2 watt. My zerocrossing circuit works very well no issues there.. Just the resistor heating problem is stopping me from manufacturing my product..
I did try it with 33k 2watt and it worked! I tested it for the last 24hours..and they did not burn out they didnt even heat up a lot.. But they are geting moderately hot but I guess they are at constant temperature.. My last question is, will the constant temperature destroy the resistor over time in a period of 1-2 months? Thanks in advance for all your help sir.
Sir thanks for your prompt reply.. But i did try 2watt 30k x2 resistors just like your circuit design but they burned out over night. Then i tried 2watt 15k x2 even they got too hot in an hour. Iv been struggling with this problem for too long.. Plz can you suggest an aleternative solution.. Thanks in advance.
Sir. I am making remote controled light and fan.. I used your circuit for the zerocrossing purpose.. It works great.. I used 2x 30k 1watt resistors we have 220v mains..it works fine but resistors heat up.. And in 4-5 hours they burn out.. What is the possible solution...how will use of 2x15k resistor affect? Sir im in an urjnt need of solution.. It will be great if you could assist me asap. Thankyou your doing a great job.
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