Is there any way to filter out TRIAC humming

[localcrack]

As I designed TRIAC based Fan Regulator with microcontroller. I add RC snubber to filter humming generated due to phase cut.
But till some times some Fan generates noise.
Is there any other way to smooth the sine curve.

[Magnox]

Use an IGBT instead of a TRIAC?

[localcrack]

Hello Magnox,
Can you give me some schematic for IGBT to control fan speed.

[Sideshow Bob]

Here is a book (it is the GE SCR manual from 1972). It may be of some help.

[borberk]

In case motor is producing noise I would check voltage waveform of motor supply regarding triggering of triac is regular.

[Magnox]

Hello Magnox,
Can you give me some schematic for IGBT to control fan speed.

Best bet is to look up IGBT app notes on onsemi's or fairchild's (and others) websites and see what fits closest to what you are doing.

[cesare]

On STM site there are several AN about PWM motor drive and you can find also several code example

PWM drive of a motor has both advantages and drawbacks when compared to a triac scheme.

Triac scheme is normally very simple and cheap for several reasons :

1) The triac can be driven directly from the microprocessor

2) The triac is switched at mains frequency so that switching losses are negligible and often you do not need a dissipator for the triac

3) Average power needed to operate the triac can be  very low because you normally need only one trigger pulse for each mains semi-cicle

4) Usually the triac scheme use a low cost capacitive supply

The main drawback of the triac drive is the noise produced by the motor while the triac is partializing. The noise is due to the High current peaks.

The PWM drive runs more smooth than TRIAC because of high PWM frequency (> 20 Khz). The drawbacks of PWM are:

1) High switching losses due to high switching frequency (normally a dissipator is required)

2) The IGBT (or high voltage mosfet ) cannot be driven directly by the microprocessor and you need some form of driver

3) The IGBT or Mosfet normally require a 10-15V gate drive and so you normally need at least two voltage to supply the regulator

4) The PWM switch must be continously switched and so requires more power than triac and so the power supply normally is not a simple capacitive one

Normally Fan speed controller are realized with triac control.

Regards



 




 

[pickit2]

you never heard of digital logic mosfet?
if you need to control a/c then how about 2 mosfet back to back.

[localcrack]

Please keep in mind that I just want to build normal small fan regulator that will control wall fan or ceiling fan.
I do not want to build giant AC Motor controller.

If you know any application notes then kindly post it.

[cesare]

Here attached an application note from ST for a fan controller.

Regards

[solutions]

If that fan has a synchronous motor, I suggest you do not use one made in China.

You are not going to solve the motor noise problem in a controller, IMO

[localcrack]

@ cesare

I checked ST application notes it uses triac firing method same as mine so it also produce humming in fan motor due to phase angle cut.

 

[cesare]

In my opinion the triac is the correct solution for a fan speed controller. A PWM control would be too complex.

Normally fan motors are some kind of induction motor that run with AC voltages. To drive an AC motor you will need 4 BJTs and the fan speed controller would be very similar to an inverter.

The motor noise depends also on the motor mechanical structure (resonances). Take also into account that some kind of motors are not dimmable.

Regards

[max]

see the attached ckt of a fan dimmer with filter.

[Brainbox]

Is the humming comming from the choke inductor, or is it comming from the fan itself?
Humming from the inductor is inherrent to the ferrite material of a choke.
In that case it would help to chose a more stable ferrite or use an air inductor.

[pickit2]

it's like a silly pissing contest, with so many opinions on a topic, with so little information supplied by the original topic starter.

[localcrack]

@ pickit2

what information is missing ?
I think most member who replied to this topic is clearly understand what I want to say.
is anything is missing then please give your suggestion

[pickit2]

@ pickit2
I think most member who replied to this topic is clearly understand what I want to say.

That's the problem, you could have used so many different components and types of motor.
every one who has worked with a triac  can have a number of fixes for noise in a fan or motor.
Some I have used in past, include snubber , multi-pulse trigger of triac and zero crossing, that being said, Who offered these?
or did they automatically think you had taken these steps to remove motor noise.
That being so, you would not have had any problem, and no post would have been made on this topic.

As said by most who answered with a part solution was hinting, to move away from a triac, The Last time we used triac in a product was in about 1992.

I still think it is a pissing contest.

 

[Sideshow Bob]

@ pickit2

what information is missing ?
I think most member who replied to this topic is clearly understand what I want to say.
is anything is missing then please give your suggestion

What strikes me is that you have not bothered taking the time to even post a schematic. Asking for help in an electronic question and not posting a schematic is asking for a futile thread like this. You have also been given a lot of pointers but seem more insterested in some magic one page easy to read "application note", that will solve all your problem. I do not think you will find one of those. Next time you ask for help in any electronic problem (or other problem for that matter). Please take the time and provide enough details so other not sitting at your workbench can really understand your problem. Good questions draw good answers

[metal]

come on, even with a schematic, he can't understand that this hum/noise is the very nature of the thing he is trying to do,  let's not forget this very basic info about such a project...

[#tester]

I just seen why, it is humming

LOOK>> It Don't know the words<LOOK

[Sideshow Bob]

Strange this thread did not give any good vibes. Now I am just humming alone and feel entertainment, how come?

[localcrack]

I use same method described on this page. On this page it uses Ardunio (Atmel AVR chips) however I am using Microchip PIC 16F877A

http://playground.arduino.cc/Main/ACPhaseControl



after zero crossing triac will be off till t1 time
Then we will give triac firing pulse of t2 time
Triac will remain on till next zero cross
again same steps repeated for the next half cycle of sine wave.

I am using following components that shown in attached schematics.

[Sideshow Bob]

Did you open the book I posted. It has a sections about noise reduction(16 and 17). Also please inform the rest of us how of the humming appear. A picture of your full setup would also be nice

[pickit2]

You missed the snubber for the opto...
did you google the data sheets?

sorry it still don't even come under the term project.

damn I just lifted this of a data sheet...