Question

A single phase AC induction motor need to be controlled by varying its input frequency. The supply frequency is a single phase with 50 Hz and the input frequency to the motor is controlled to be 12.5 Hz. Design a Full-wave rectifier (Cycloconverter), show the conversion of 5 cycles, and explain its operation. And show how the output voltage of Cycloconverters can be controlled to get a waveform shape near sine wave.

Answer #1

From first image consider the circuit and general operation of convrter....

If the available power source is a single-phase, 60 Hz, ac
supply and a separately excited DC motor is to be fed from this
source, configure possible drive circuits for:
i) One-Quadrant Operation,
ii) Two- Quadrant Operation
iii) Four- Quadrant Operation
Hints: For one-quadrant operation, the motor control circuit is a
half-wave controlled rectifier or a semicontrolled converter and
the driver for the separately excited is a semi-controlled
converter with a freewheeling diode using the ac supply
source.
For two-quadrant...

The effect of single- and three-phase diode rectifiers on
harmonics, distortion and ripple.
Variable-frequency converters for induction motor drives.
The impacts of non-sinusoidal excitation on induction
motor.
The principles of three-phase sine-triangle PWM-modulator.
Describe the properties of such a modulator in its linear,
overmodulation and square wave areas. Which harmonics are presents
in each case?
Benefits of resonant converters. Describe one resonant
converter.

Design an Op-Amp phase shift circuit that must accept a
sine waveform voltage at its input ???
(?) = 10 sin (120??) mV,
and must provide at its output, an output voltage of 1.2 Vrms and
with an offset of −120 ° with respect to the input
signal.

A three phase Wye-connected 460 v, 4 poles, 60 Hz wound rotor
induction motor has the following parameters:
R1=0.3, R2=0.15, X1=0.5,
X2=0.2, Xm=14
The total friction, windage, and core loss is constant at 400 w.
The motor is working at its rated voltage and drives its load at
1764 rpm.
a)Calculate the input current and the input power.
b)Calculate the output mechanical power and torque and motor
efficiency.
c)Calculate the starting current of this motor and compare it
with its...

A three-phase, 60-Hz, 4-pole, 440-V (line-line, rms)
induction-motor drive has a full-load
(rated) speed of 1746 rpm. The rated torque is 40 Nm. Keeping the
air gap flux-density
peak constant at its rated value.
The frequency and voltage of the motor from above are adjusted
such that the fan speed is changed to 600 rpm. The motor should be
operating at 3% slip and rated Bm. What is the motor
efficiency?

A three-phase, 280 V, 60 Hz, 20 hp, 1710 r/m. Y-connected
induction motor has the following impedances in ohms per phase
referred to the stator circuit:
R1=0.12 Ω.
Rˈ2=0.1
Ω
X1=Xˈ2=0.25 Ω
Xm=10 Ω
A total rotational loss are 400 W. The core loss is lumped in
with the rotational losses. For a slip of 0.05 at the rated voltage
and rated frequency. Find:
a) The numbers of poles of the motor.
b) The stator current.
c) the power factor...

A 210 V, 1200 rpm, 10 A separately excited motor is controlled
by 1-
phase fully controlled converter with an ac source voltage of 230
V,
50 Hz. Assume that sufficient inductance is present in the
armature
circuit to make to motor current continuous and ripple free for
any
torque greater than 25% of rated torque, and Ra = 1.5 Ω.
i. What should be the value of the firing angle for the rated
torque at motoring +ve (1200rpm)
ii....

Q4)
A three-phase, 104 kW, 3300 V, 50 Hz, Y-connected induction
motor delivers full output power to a
load connected to its shaft. The full-load slip is 0.02 and
full-load power factor is 0.85 lagging. If the stator
copper loss is 2400 W, the stator core loss is 3500 W, and the
friction and windage loss is 1200 W. Calculate:
(i) The developed mechanical power.
(ii) The air gap power.
(iii) The rotor copper loss.
(iv) The efficiency of the...

A major manufacturer of home and office air conditioners uses a
½ hp, single-phase induction motor that has an efficiency of 72% at
its average power output level. Several large volume customers
indicated that they would be willing to pay a larger initial
investment in air conditioners if they could recover this increased
investment during the warranty period, which is 2 years. The
typical office air conditioner in which they are interested runs
approximately 8 hours per day during 260...

The following test data apply to a 7.5-hp, three-phase, 220-V,
19-A,60-Hz, four-pole induction motor with a double-squirrel-cage
rotor of design class C (high-starting-torque, low-starting current
type): Test 1: No-load test at 60 Hz; Applied voltage V = 219 V
line-to-line; Average phase current I1,nl = 5.70 A; Power Pnl =380
W; Test 2: Blocked-rotor test at 15 Hz; Applied voltage V = 26.5 V
line-to-line; Average phase current ll,bl = 18.57 A; Power Pbl =
675 W; Test 3: Average...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 39 minutes ago

asked 56 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 3 hours ago

asked 3 hours ago