Download test – laboratory

ANSWER 5 out of 6 QUESTIONS
1 QUESTION for each LAB. EXPERIMENT
SET OF QUESTIONS
Exp. A – MEASUREMENT OF PARAMETERS OF INDUCTION MOTORS
a) Draw equivalent circuit of induction slip-ring motor with additional resistors in
the rotor circuit and name its components. Which components are measured
during perfect no-load test ?.
b) Describe the blocked-rotor test procedure (in points). Draw equivalent circuit of
induction for the test.
Exp. B – SPEED CONTROL OF INDUCTION MOTORS
a) Why does the frequency of supply influence the value of the rotation speed of
the induction motor?. Draw a torque vs. speed characteristics to illustrate for
scalar control to illustrate it.
b) What physical quantity is kept constant in case of U/f control? Draw
relationship of the voltage / frequency of the inverter. Which control scheme is
more advanced : vector or scalar ?.
Exp. C - DC GENERATOR
a) Explain differences in the curves for the separately excited and shunt connected
DC generators. Draw measurement circuits for both.
b) What differences occurred as a result of the reversed shunt field polarity ?
Exp. D – ELECTROMAGNET MODELLING
a) What is FEM ?. What is the shape of elements used in FEMM software for area
division?.
b) Name 3 of 4 methods used to calculate the force in case of FEM modelling.
Describe the procedure for one of them.
Exp. E – SERVO MOTOR
a) What type of switches is used in servo drive ?. Describe their function in
operation of the system.
b) What types of position selection do you know ?. Describe one of them.
c) What type of machine can be used as servo motor : DC, induction or
synchronous ?. Explain briefly why.
Exp. F – STEPPER MOTOR
a) What is the main purpose in application of stepper motor : speed or position
control ?. Explain briefly why.
b) Can stepper motor work without position feedback ?. Briefly explain your
opinion.
c) What type of machine can be used as stepper motor : DC, induction or
synchronous ?. Explain briefly why.