Brief discuss the operation of a split phase single phase single
induction motor with respect to its construction, current
relationship and torque characteristics. Illustrate your answer by
means of diagram
a) What is the advantages of using a wound-rotor type of
induction motor? Under what conditions?
b) When starting a wound rotor induction motor, what is the
supposed value of resistance of the slip-ring starter?
c) What is the wound rotor method of speed control?
The single-phase equivalent-circuit parameters for a three-phase
induction motor in ohms-per-phase are
R1=0.17 R2=0.24 X1=1.05
X2=0.87 Xm=82.1 Rc=435
For a slip of 5 percent, and a terminal voltage of 460 V, line
to line, calculate:
A) Calculate the motor phase current and input real and reactive
power.
B) Calculate the mechanical output power and the power
dissipated in the rotor. You might assume that the motor friction
and windage losses are 270W
C) Calculate the motor core loss and the...
The test results for the approximate equivalent
circuit of a three-phase induction motor are shown below.
No-load test: equivalent applied voltage 120 V, input current 5 A,
equivalent input 480 W
Restraint test: Applicable voltage 20V, input current 40A,
equivalent input 480W
Determine the equivalent circuit constants of Rc, Xm,
Rs + Rr, and Xs + Xr
when friction and wind losses are ignored.
Answer - 30Ω, 40Ω, 0.3Ω, 0.4Ω
A 400V, three phase, 50Hz, 4 pole induction motor is operating
at a per unit slip of 40KW from the suppply. Under these conditions
stator losses amount to 2.2 KW and rotational losses due to
friction and windage amount to 1.4KW. Calculate the net horsepower
and torque developed.
A 400V, 2 pole, 50 Hz, three-phase induction motor is drawing 60
A at 0.85 PF lagging. The stator copper losses are 2 kW, the stator
core losses are 1.8 kW and rotor copper losses are 700 W. The
friction and windage losses are 600 W, the stray loss 100 W, and
rotor core loss 100 W.
Find the following quantities:
a. The air gap power.
b. The developed mechanical power.
c. The output power.
d. The efficiency of the...
A 6-pole and three-phase induction motor has synchronous speed
of (1000) RPM.
a) Find the no-load and full-load operating speed of motor for
the cases given,
1. 2.5Hz electrical frequency of rotor for no-load
condition.
2. 6.3Hz electrical frequency of rotor for full-load
condition.
b) Find the speed regulation of motor by using parameters found
above.
c) Determine the electrical frequency of rotor under full-load
condition so that speed regulation would be equal to 5%?
(Electrical frequency of rotor for...
A three phase 30 hp 460 volt 60 hz, 1770 rpm design B induction
motor with class F insulation and service factor of 1.0 is
operating at rated shaft load in a 40 degree C environment and has
an expected 20 yr life. A maintenance check shows line to line
voltages to be 449.2 V, 431.3 V and 462.4 volts. The percent
unbalanced voltage for this motor is:
the expected temperature rise equals?
The expected insulation life equals?
the rerating...
A three phase 10kW, 1700rpm, 60Hz, four poles, Y connected
induction motor has a no-load speed of 1750rpm. The rotational
mechanical losses are constant and equal to 500W. The core losses
are constant and equal to 300W. The copper losses in the stator
equal to the copper losses in the rotor at full load. If the rotor
resistance per phase is 0.25?, calculate the following:
a.The frequency of the induced current in the rotor circuit at full
load.
b.The percentage...