The wattage rating for a ceiling fan motor is in the range of 50 to 150 W. if the ceiling Fans size ranges from 36 inches to 56 inches then the total wattage use is 55 to 100 watts.. A 48-inch ceiling fan will use 75 watts.
Phosphorus (P) has 15 electron i.e 2,8,5. Hence the number of electron in its outermost orbit is 5.
Silicon (Si) has 14 electron i.e 2,8,4. Hence the number of electrons in its outermost orbit is 4.
Magnetic Field Strength (H) gives the quantitative measure of strongness or weakness of the magnetic field.
H = B/μo
B = Magnetic Flux Density
μo = Vacuum Permeability
The magnetic Field strength at the center of circular loop carrying current I is given by
B = μoI/2r
B/μo = I/2r
H = I/2r At/m
Where r = Radius
The rotor of the synchronous machine carries a field winding that is supplied with d.c. through two slip rings by a separate d.c. source. Synchronous Rotor construction is of two types, namely :
Salient (or projections) pole type.
Cylindrical type (or non-salient pole type)
In this type, salient poles are mounted on a large circular steel frame which is fixed to the shaft of the alternator.
The rotors of salient-pole rotor machines have concentrated winding on the poles and a nonuniform air gap.
Salient pole generators have a large number of poles. sometimes as many as 50, and operate at lower speeds.
The synchronous generators in hydroelectric power stations are of the salient pole type and are driven by water turbines.
The rotors are shorter axial length but have a large diameter.
When flux enters into the air gap, it passes through the air gap in terms of parallel ﬂux lines. There exists a force of repulsion between the magnetic lines of force which are parallel and having the same direction. Due to this repulsive force, there is the tendency of the magnetic flux to (spread out) at the edge of the air gap. This tendency of ﬂux to spread out at the edges of the air gap is called magnetic fringing.
Magnetic fringing increases the effective cross-sectional area of the air gap reduces the flux density. So leakage, fringing, and reluctance should be as small as possible. This is possible by choosing a good magnetic material and making the air Magnetic fringing gap as narrow as possible.
Voltage Scale Span of instrument = Vmax − Vmin
Vmax = 5 V
Vmin = −5V
Span = 5 −(−5) = 10 V