Fan Regulator Connection Diagram and Internal Circuit Explanation

Fan Regulator Connection Diagram and Internal Circuit


Fan regulator is a very very much usable electrical or electronic device. We are all using the fan regulator in our house with Fan. Fan Regulator is a device by which we can control the speed of rotation of the fan. Today we are going to know How fan regulator works, fan regulator internal circuit and Fan Regulator Connection Diagram.


How Conventional Fan Regulator works?


This is Old Fan Regulator. As you see in the below figure, the construction of a conventional fan regulator is very simple. There is some series connected resistance that can be adjusted by rotating the knob of the regulator. This conventional fan regulator is to be connected in series with the fan and power supply. By moving the knob we can increase or decrease the resistance value. If we increase the value of resistance the voltage drop across the resistor will be increased so the voltage across the fan motor will be decreased and ultimately the speed of the fan will be decreased and Vice-versa.

click on the image to enlarge


conventional fan regulator circuit, fan regulator connection



The disadvantage of Conventional Fan Regulator is that it causes a huge amount of heat loss or I2R loss because there are a number of resistors and that causes heat loss across the resistors and eventually this reduces the life of this regulator and also it affects your electricity bill so.


How does Electronic Fan regulator Work?

To reduce power loss nowadays electronic fan regulator is mostly used. Electronic fan regulator uses semiconductor devices. 

An electronic fan regulator has the following parts,


  1. TRIAC
  2. DIAC
  3. Capacitor
  4. Fixed resistor
  5. Variable resistor or Potentiometer




As you see in the below figure the TRIAC is connected in series with the Fan and the supply. The TRIAC can conduct AC current when a pulse signal is given to the gate terminal of the TRIAC. Here the DIAC is used to trigger the TRIAC. First, the capacitor will be charged through the fixed and variable resistor resistors. When the capacitor is fully charged it starts discharging through the DIAC. Now the TRIAC will be triggered and it starts conducts, therefore, the current will flow from the supply through the TRIAC and the fan. 

Actually, the TRIAC remain ON for a short time duration and remain OFF for a short time duration according to the charging and discharging of the Capacitor. This process causes reduce the value of the average voltage across the Fan and ultimately the speed of the fan will be decreased. 



The variable resistor or potentiometer is used to change the time constant of the capacitor. That means when we increase the resistance by moving the potentiometer knob the charging time of the capacitor will be increased and this causes the TRIAC to remain OFF for more time. This process causes to more decrease the value of the average voltage across the fan and the speed of the fan also more decreased.


The fixed resistor is used to protect the capacitor from the full voltage. That means if we did not use the fixed resistor the full voltage will appear across the capacitor if we decrease the variable resistance to zero that may damage the capacitor

Internal Circuit of Fan regulator:

Here the internal circuit diagram of an electronic fan regulator shown below

click on the image to enlarge



Fan Regulator Connection Diagram and Internal Circuit Explanation Fan Regulator Connection Diagram and Internal Circuit Explanation Reviewed by ETechnoG on 20:11 Rating: 5
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