Fan regulator

fan regulator containing types of regulators, working ,circuit diagrams,advantages and disadvantages

1. FAN REGULATOR Hardware Assignment ppt

2. content Fan regulator Types of fan reguator Resistive regulator Phase angle controlled regulator Triac Diac Inductive type fan regulator Capacitive type fan regulator Working of fan regulator Advantages and Disadvantages

3. Fan Regulator Fan Regulators have an important place in the electrical switch boards. Fan Regulators are very simillar to light dimmers . Their function is regulate/control the speed of the fan and provide a convenient environment environment for the residents. The traditional regulators which are bulky use a resistance having taps and connected in series with the fan.when we move the knob different amount of resistance gets inserted in the circuit

4. Types of Fan Regulator Currently Fan Regulators are of these four types: 1) Resistive Regulator 2) Phase angle controlled Regulator 3)Inductive Regulator 4)Capacitive Regulator

5. Resistive Regulator This is the most coomon type in household celing fans . It works by providing different taps on a wire wound resistor connected in series with the fan =>Cost-effective => Considerable power loss as heat,especially at lower speeds,making it inefficient => Bulky,lack of aesthetic appeal =>very high energy consumption Advantages disadvantages

6. Phase Angle Controlled Regulator Phase angle controlled regulators employ active devices such as DIAC and TRIAC. The basic principle is to change the firing angle of the TRIAC in order to change the voltage across the fan =>continuous speed controll =>low power consumption as compared to resistive type regulators =>Speed control not linear. =>Expensive as compared to resistive fan regulators. =>Produces humming sound that is disturbing. =>Higher failure rate as active devices are suspectible to power supply transients and interference. =>Causes EMI/RFI interference creating disturbances in TV and radio sets Advantages disadvantages

7. TRIAC TRIAC is a three terminal device stands for “Triode For Alternating Current” It is a three electrode semi conductor device That will conduct in either direction when triggered by a positive and negetive signal at the gate electrode. When requiring to switch both halves of an AC waveform there are two options that are normally considered. One is to use a TRIAC, and the other is to use two thyristors connected back to back - one thyristor is used to switch one half of the cycle and the second connected in the reverse direction operates on the other half cycle. As there are two options the advantages and disadvantages of using a TRIAC must be weighed up. Despite what may seem like a number of disadvantages, it is still the best option for many circumstances. However when using a TRIAC, it is necessary to be aware of its limitations so that these can be satisfactorily addressed and overcome should they affect the operation of the overall circuit in any significant way. TRIAC adva ntages and disadvantages

8. TRIAC Applications TRIACs are used in a number of applications. However they tend not to be used in high power switching applications - one of the reasons for this is the non-symmetrical switching characteristics. For high power applications this creates a number of difficulties, especially with electromagnetic interference. However TRIACs are still used for many electrical switching applications: Domestic light dimmers Electric fan speed controls Small motor controls Control of small AC powered domestic appliances

9. DIAC The DIAC is a full-wave or bi-directional semiconductor switch that can be turned on in both forward and reverse polarities. The DIAC gains its name from the contraction of the words  DI ode   A lternating  C urrent. The DIAC is widely used to assist even triggering of a TRIAC when used in AC switches. DIACs are mainly used in dimmer applications and also in starter circuits for florescent lamps. The DIAC is essentially a diode that conducts after a 'break-over' voltage, designated VBO, is exceeded. When the device exceeds this break-over voltage, it enters the region of negative dynamic resistance. This results in a decrease in the voltage drop across the diode with increasing voltage. Accordingly there is a sharp increase in the level of current that is conducted by the device. The diode remains in its conduction state until the current through it drops below what is termed the holding current, which is normally designated by the letters IH. Below the holding current, the DIAC reverts to its high-resistance (non-conducting) state. Its behaviour is bi-directional and therefore its operation occurs on both halves of an alternating cycle. Operation

10. DIAC Applications Typically the DIAC is placed in series with the gate of a TRIAC. DIACs are often used in conjunction with TRIACs because these devices do not fire symmetrically as a result of slight differences between the two halves of the device. This results in harmonics being generated, and the less symmetrical the device fires, the greater the level of harmonics produced. It is generally undesirable to have high levels of harmonics in a power system

11. Inductive type Fan Regulator An inductive type fan regulator has a tapping on the winding of the transformer and the inductive resistance is varied to achieve variation in speed. speed decreases with the increase in the number of turns of the inductance coil winding. low heat power dissipation =>low power factor. =>quite costly. =>heavy sand bulky. Note: Advantages Inductive type Fan Regulator

12. Capacitive type Fan Regulator Basic principal to control the voltage across the fan C is directly proportional to 1/v As c increases,v decreases.thus,the voltage across the fan increases.therefore,the speed increases R s is a series resistance which is used in series with the capicitor in order to limit the current flowing to the capacitor to a safe value. R p is a parallel resistance which serves as a discharging path for the capacitor for each supply cycle. Capacitive Fan Regulator – block diagram Purpose of R s and R p

13. Advantages of a capacitive Fan Regulator Energy efficient No humming sound during operations Speed is linear. High reliability as compared to electronic type regulator Becauses of size only marginal design is possible for film capacitor Fire hazard is , hence,the only failure mode. D is dvantages of a capacitive Fan Regulator

14. Working of Fan Regulator Series resistors are switched in with the motor to slow it down. Doing so reduces the voltage at the motor and it turns more slowly. However there is power dissipated in the resistor a significant fraction of the total power so it wastes 20 30 40 % of the power depending upon the speed and if the fan is on 24 hours a day it adds up. An alternate speed control can be effected by using capacitors whose impedance matches that of the resistors. You get the voltage drop at the motor and the same speed drop. However the capacitor returns power to the power line out of phase thus dissipating no power in the capacitor except its DCR component. Thus it should be more efficient, saving a few watts in apparent power. If there's any disadvantages I would guess the capacitor regulators cost a bit more. Using with capacitors Using with Resistors

15. Advantages of Electronic Fan Regulator They provide a continuous speed control. Power saving at all the speeds. Smaller size and weight.

16. Disadvantages of electronic Fan Regulator Although cheap the biggest problem with such a regulator is that a considerable amount of energy is lost in from of heat through the resistance. When the fan is operating at low speed the power loss is significant.

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