Advantages of stepper motors:
i) They can be directly controlled by computers, micro-processors and
programmable controllers.
ii) Precision control of speed without using closed loop feedback.
Applications:
i) Operation control:
Such motors used for operational control in computer peripherals, textile
industries, IC fabrications and robotics etc.
ii) Incremental motion:
Applications requiring incremental motion are typewriters, line printers, tapedrivers,
floppy disk drivers, numerically controlled machine tools, process-control
systems and X-Y plotters.
Others:
It includes commercial, military and medical applications where these motors
perform functions as mixing, cutting, striking, metering, blending and purging.
They also take part in manufacture of packed food stuffs, commercial endproducts
and even the production of science fiction movies.
Permanent Magnet Stepper motor:
It has wound stator poles and permanently magnetized rotor poles. It has a
cylindrical rotor. Its direction of rotation depends on the polarity of stator current.
The stator has projecting poles. Rotor has 2 poles whereas stator has 4 poles and
the two stator poles are energized by one winding, the motor has two windings or
phases.
Working :
When a particular stator phase is energized, the rotor magnetic poles move into
alignment with excited stator poles. The stator wdgs. A and B can be excited with
either polarity current (A+ refers to the +ve current i+
A in phase A and A- to
negative current (i-
A). Fig, shows condition when phase A is excited with the
current i+
A. Here = 0o. If excitation is now switched to phase B, the rotor rotates
by a full step of 90o clockwise direction. When phase A is excited with –ve
current i-
A, the rotor turns through another 90o in clockwise direction. Similarly
excitation of phase B with i+
B further turns rotor through another 90o in same
direction. After this excitation of phase A with i+
A makes rotor run through one
complete revolution of 360o.
gregorymasila answered the question on February 22, 2018 at 16:50
- Explain the different methods of starting an induction motor.(Solved)
Explain the different methods of starting an induction motor.
Date posted: February 22, 2018. Answers (1)
- What are the two types of constructions that are employed in synchronous machines?
Explain the two machines and give with reasons which of them are simple...(Solved)
What are the two types of constructions that are employed in synchronous machines?
Explain the two machines and give with reasons which of them are simple to model
and analyze
Date posted: February 22, 2018. Answers (1)
- Explain the construction and working principle of a transformer(Solved)
Explain the construction and working principle of a transformer
Date posted: February 22, 2018. Answers (1)
- Write short note on Differential Relay(Solved)
Write short note on Differential Relay
Date posted: February 22, 2018. Answers (1)
- Write short note on Application of dielectric heating(Solved)
Write short note on Application of dielectric heating
Date posted: February 22, 2018. Answers (1)
- Describe the construction, principle of operation and advantages of SF6 circuit
breaker.(Solved)
Describe the construction, principle of operation and advantages of SF6 circuit
breaker.
Date posted: February 22, 2018. Answers (1)
- Write short note on following: (a) Condenser in Thermal power plant (b) Control of nuclear reactor(Solved)
Write short note on following:
(a) Condenser in Thermal power plant
(b) Control of nuclear reactor
Date posted: February 22, 2018. Answers (1)
- Explain the principle of operation of two phase servo motor. Draw its torque-slip characteristics.(Solved)
Explain the principle of operation of two phase servo motor. Draw its torque-slip characteristics.
Date posted: February 22, 2018. Answers (1)
- (a) Why does the induction motor not rotate at synchronous speed?
(b) Describe with the aid of diagram of connection, phasor diagram and torque-slip
characteristics, the...(Solved)
(a) Why does the induction motor not rotate at synchronous speed?
(b) Describe with the aid of diagram of connection, phasor diagram and torque-slip
characteristics, the working of capacitor-start single phase induction motor.
Date posted: February 22, 2018. Answers (1)
- Explain two important functions served by the damper winding in a synchronous motor. State the various applications of synchronous motor(Solved)
Explain two important functions served by the damper winding in a synchronous motor. State the various applications of synchronous motor.
Date posted: February 22, 2018. Answers (1)
- Write short notes on Switched reluctance motor(Solved)
Write short notes on Switched reluctance motor
Date posted: February 22, 2018. Answers (1)
- What are the advantages of high voltage transmission and its limitations(Solved)
What are the advantages of high voltage transmission and its limitations
Date posted: February 22, 2018. Answers (1)
- What are the criteria for the classification of transmission lines as short, medium and long lines?(Solved)
What are the criteria for the classification of transmission lines as short, medium and long lines?
Date posted: February 22, 2018. Answers (1)
- Describe the construction of a lead acid cell and explain the process of charging and discharging of the cell(Solved)
Describe the construction of a lead acid cell and explain the process of charging and discharging of the cell.
Date posted: February 22, 2018. Answers (1)
- Write notes on the following
(i) Differential relays.
(ii) Inductive interference in a transmission line.
(iii) Nickel-cadmium cells.(Solved)
Write notes on the following
(i) Differential relays.
(ii) Inductive interference in a transmission line.
(iii) Nickel-cadmium cells.
Date posted: February 22, 2018. Answers (1)
- Describe a typical coreless type of induction furnace and its special features(Solved)
Describe a typical coreless type of induction furnace and its special features
Date posted: February 22, 2018. Answers (1)
- Describe the primary and back-up protection features that are provided for transmission lines(Solved)
Describe the primary and back-up protection features that are provided for transmission lines.
Date posted: February 22, 2018. Answers (1)
- List out the important advantages of HVDC transmission(Solved)
List out the important advantages of HVDC transmission
Date posted: February 22, 2018. Answers (1)
- Give a list of the factors involved for selecting a factory drive(Solved)
Give a list of the factors involved for selecting a factory drive
Date posted: February 22, 2018. Answers (1)
- What are the factors which are involved in circuit breaker rating?(Solved)
What are the factors which are involved in circuit breaker rating?
Date posted: February 22, 2018. Answers (1)