AC MACHINES

Question 1

frequency of Generated EMF

Answer 1

f= PNs/120

Question 2

generated EMF Equation per phase

Answer 2

E= 4.44fONKpKd

Question 3

pitch factor/ coil factor Kp

Answer 3

sin (P/2) or cos (alpha/2)
P= (coil pitch/slot pitch) (180 deg)

Question 4

distribution or breadth factor Kd

Answer 4

sin (nd/2) / n sin(d/2)
d = 180/ slots per pole

Question 5

synchronous impedance

Answer 5

Zs = Eoc/Isc

Question 6

stator copper loss alternator

Answer 6

(3)(I phase)^2 (Reff)

Question 7

rotor copper loss alternator

Answer 7

field current times field voltage

Question 8

alternator efficiency

Question 9

frequency after adding a load

Answer 9

f1= f0-slope(Load 1)

Question 10

slip speed

Answer 10

Ns- Nr

Question 11

percent slip

Answer 11

](Ns-Nr) Ns] x 100%

Question 12

rotor frequency

Answer 12

fr=slip(frequency)

Question 13

blocked rotor voltage per phase

Answer 13

a= rotor turns/ stator turns
E br per phase = a (E stator voltage per phase)

Question 14

rotor voltage per phase

Answer 14

s (Ebr per phase)

Question 15

current at blocked rotor condition

Answer 15

Ir/phase = E br / Zr per phase
Zr per phase = sqrt [(rotor resistance/s)^2 + rotor reactance^2]

Question 16

induction motor rotor copper loss

Answer 16

RCL = 3 ( Ir/phase) ^2 (Rotor resistance per phase)
RCL = sRPI

Question 17

Voltage regulation alternator

Answer 17

[Vnl -Vfl] /Vfl x 100

Question 18

Alternator power stage

Question 19

Induction motor power stage

Question 20

Rotor reactance

Answer 20

Xr = S(X2)

Question 21

rotor copper loss induction motor

Answer 21

RCL = 3 Ir^2 Reff

Question 22

rotor power input

Answer 22

RPI = RCL/ S

Question 23

rotor power developed

Answer 23

RPD = RCL (1-s / s)

Question 24

maxwell to weber conversion

Answer 24

1 weber / 1x10^8 Mx