1) How is the real power controlled in a grid-connected wind
turbine employing a permanent-magnet synchronous generator (PMSG)
with rectifier and inverter? *
rotational speed
inverter output current
generator output voltage
rectifier output voltage
inverter output voltage
2) How do you compare the size of power electronics in a
grid-connected 1 MW variable-speed wind turbine employing DFIG and
PMSG? *
same
no power electronics in DFIG
no power electronics in PMSG
smaller in PMSG
smaller in DFIG
3)What is the...
a. For an induction motor, differentiate between
synchronous speed, rotor speed and slip speed.
b. State the two basic types of construction used for the rotors of
induction motors. Which is the
most rugged and explain why.
c. Draw full equivalent circuit for one phase of an induction motor
with all parameters labelled
and named.
d. Draw and explain power flow diagram of 3 phase induction
motor.
e. Mention four (4) components of induction machine. Explain
briefly the function of...
Synchronous and Induction Machine Questions
Q1: How do we find induced voltage, frequency, synchronous
reactance, generated voltage at pf for a synchronous generator?
Q2: How do we find slip and number of poles, speed of rotor,
load torque, induced torque in a induction motor?
Q3: Based on an induction motor test(no-load, blocked-rotor
test)- what are the circuit parameters and how do we draw the
circuit?
Q4: For a synchronous machine, how do we draw phasor
diagram?
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...
The synchronous generator or alternator is an electrical machine
that converts the mechanical power
from a prime mover into an AC electrical power at a particular
voltage and frequency.
The synchronous motor always runs at a constant speed called
synchronous speed. A three phase, 8
pole, synchronous Generator is coupled to a diesel engine running
at 500 rpm. It supplies an induction
motor which has a full load speed of 1440 rpm. Find the percentage
slip and number of poles...
Imagine a superfast fish that is able to swim faster than the
speed of sound in water. Would this fish produce a “sonic
boom”?
Use the concepts from this module to explain why flying bees
buzz.
If the handle of a tuning fork were to be handled firmly against
a table, would the sound from the tuning fork change? If so, what
would change?
The strings of a harp have different length in order to produce
different notes. However, given...
It is found that the real GDP per capita of developing countries
grows faster than developed countries at the same period. Explain
this phenomenon in the light of diminishing returns to capital.
2) China’s real per capita GDP has been growing significantly
faster than that in the U.S. – China’s growth rate was about 10%
several years ago, compared to about 3% for the U.S.
a) Using the Solow growth model (with no technological
progress), is there reason to believe this disparity in growth
rates will disappear in time? What about the disparity in income
levels per person?
b) How is your conclusion affected if you were told that China
has a...
Does a stiffer spring undergo slower or faster damping than a
less stiff spring of the same length?
( A brief explanation in detail would be very helpful, thank
you!)