I m trying to design a hum free 5 speed electronic fan regulator. Input voltage is 220vac. The cycles/hz must remain at 50 cycles/hz at all speeds. can anybody help me out?

 

I m trying to design a hum free 5 speed electronic fan regulator. Input voltge is 220vac. The cycles/hz must remain at 50 cycles/hz at all speeds. can anybody help me out?

 

While I don't know the answer I am quite sure that at least the following must be known:

A. What kind of motor.

B. What voltage, power, etc.

C. Is the "hum" you describe something that is audible and originates in the motor, is it in the form of electronic interference ....etc?

D. What this is for ....

__________________
stevez

 

You need to specify what type of motor it is, and how the speed can be changed.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Motor is Ac type. the one used in ceiling fans
input voltage means the input voltage to the circuit like u hav 110 in us and 240 in uk.
hum is the sound produced by the motor when the cycles r less then r greater than 50 and the circuit is for the ceiling electric fan.
wat i require is that at speed 1 the ceiling fan should b doing 350rpm with 50cycles
at speed 2 the ceiling fan shuld move at 290rpm with 50 cycles
at speed 3 240rpm with 50 cycles
at speed 4 180rpm with 50 cycles
at speed 5 120 rpm with 50 cycles

reducing voltage is not a prob. d prob i m facing is that i m unable to contorl d cycles. i want to make the cycles stable at 50...

 

i m trying to reduce input voltage but doen't want the cycles/hz to change. i-e i want to keep the cycles constant at 50 cycles/hz. Iss there anyway to achieve this using capactors and resistors?

 

i m trying to reduce input voltage but doen't want the cycles/hz to change. i-e i want to keep the cycles constant at 50 cycles/hz. Iss there anyway to achieve this using capactors and resistors?

 

Input voltage to what? A farm animal?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

Generally ceiling fan motors are induction motors and speed control is achieved via an autotransformer or series capacitor which reduced the voltage.
The motor gets a lower voltage, less torque, slip increases and reduced speed.

I have succesfully modified 3 speed ceiling fans to 6 speed as well an plug in fans which often are 3 speed to 6 speed to have a very slow speed available.

I use capacitors and a bypass switch.

Ensure the caps are mains rated. 600 Volts ac or more and ensure safe wiring practises, because 220 volts is dangerous if you don't know what you are doing.

__________________
There are more ways to get to Rome.

Electricity, Electric clocks, Meters and Trains are great.

 

In most waveforms, amplitude is independent of frequency. Give us some more information.

 

You are describing the exact function of a transformer(step-down).

 

The easiest probably is to get a variac. Or you can try using "bucking" configuration of transformer--see here (check the bottom most of the page). You can build this transformer on your own using wire coil and perhaps a ferrite core.

 

Hi Atif_butt82,

Actually you can reduce the voltage with just resistors (or a step down transformer), with out changing the frequency.

**Just use extreme caution if your project uses household AC. It can be lethal if your not absolutely sure of your wiring, or if you make contact between the hot side and ground** If you ever feel a tingling when working with AC, you're making contact in a very bad way...

Using a resistor to drop the voltage reduces the amplitude of an AC waveform, but doesn't do anything to change the frequency. You will need to take into account the resistors' power rating, otherwise they could go up in smoke!

Some AC circuits with capacitor, and/or inductors, will change the phase angle of an AC circuit, but this doesn't change the actual frequency of the signal.

If you could post the schematic, or at least a detailed description of your circuit, it would be easier to give a more detailed answer.

 

Now you have three nearly identical threads going.

 

As Atif butt82 requested a schema to be drawn via a PM here it is.

Most portable fans have 4 switches, mechanically interlocked ( drawn in the box of schema ) to get 3 speeds. Leave as it is.
Celing fans may have a capacitor arrangement with a rotary switch or an autotransformer.

Add the extra switch and capacitor C 3.
By choosing the correct value the desired low speed can be obtained.

A bit of experimenting may be required.

The X2 class mains rated Caps work great. My room ceiling fan has 2 x 0.47 µF 250 Vrms in parrallel for C3 to obtain the lower 3 speeds.
(That is for 240 V 50Hz.)

As said before, you are working with lethal voltages so ensure that all wires are mains rated and sleeved so no danger of electrocution exists.

Hope this helps,

Regards, Raymond

Attached Images

6 speed fan controller.GIF (22.6 KB, 13 views)

__________________
There are more ways to get to Rome.

Electricity, Electric clocks, Meters and Trains are great.