TO FIND THE POWER FACTOR OF COIL OF FAN

APPARATUS REQUIRED

i) The given Fan

ii) A.C Voltmeters

iii) Non-inductive resistance

THEORY

The power factor of the coil of a fan is given by the relation,

CosΦ = V² – (V²R + V_L)/2V_R.V_L 

CosΦ = power factor of the fan

V = p.d supplied is p.d of A.C source

V_R = p.d supplied across non- inductive resistance R 

V_L = p.d across the fan.

PROCEDURE:

ii) First of all, connections are made as shown in the figure.

ii) The p.d (V) of the A.C source is noted from voltmeter (V). Then the fan is opened at a high level.

iii) Adjust the value of by VR varying the value of R is a suitable position and corresponding reading V₁ is noted.

iv) The process is repeated with the fan at medium and low speed.

v) The operation (ii) and (iii) are repeated once again by changing the value of VR to another value.

OBSERVATION

S.N.	Speed of the fan	‘V’ volt	VR volt	VL volt	V2-(V2R+VL2)/2VRVL
1	High	200	20	180	1
2	High	200	25	170	0.99
3	Medium	200	23	175	0.91
4	Medium	200	18	186	0.95
5	Low	200	9	190	1
6	Low	200	12	186	0.97

RESULT

Thus the power factor of the given fan at high speed is 1-6 at medium speed is 9 and that at low speed is 0.97

CONCLUSION

Thus the value of power of the coil of the given far was determined .

PRECAUTION

i) After checking the circuit, only the main line should be connected.

ii) During varying resistances and cure should be taken high voltage A.C current flows through it.

iii) P.d and current should be carefully measured. The small error leads to the wrong value.