Description : Which rotor is use for high speed in turbo alternators?
Answer :
Non-salient pole rotor is used for high speed in turbo alternators.
asked
Mar 18, 2018
by
anonymous
Description : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents
Answer :
The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) has d -axis current only
asked
Apr 29, 2018
by
anonymous
Answer :
If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.
asked
Mar 20, 2018
by
anonymous
Description : what will happen when excitation of an unloaded salient pole synchronous motor suddenly gets disconnected?
Answer :
When excitation of an unloaded salient pole synchronous motor suddenly gets disconnected the motor will stop.
asked
Mar 18, 2018
by
anonymous
Answer :
Locked rotor current of a shaded pole motor is slightly more than full load current.
asked
Mar 20, 2018
by
anonymous
Description : An electric motor in which both stator field and rotor rotates with same speed is called?
Answer :
An electric motor in which both stator field and rotor rotates with same speed is called synchronous motor.
asked
Mar 18, 2018
by
anonymous
Answer :
In a shaded pole single-phase motor, the revolving field is produced by the use of shading coils.
asked
Mar 20, 2018
by
anonymous
Description : Compare the salient features of LED and CFL based on: i] Lamp Efficiency ii] Life span
Answer :
Parameter LED CFL Lamp Efficiency High (more than 70 lumen per watt) Comparatively less (50-60 lumen per watt) Life span (in working hours) 10000 3000
asked
May 3, 2020
by
anonymous
Description : List any four salient features of 8085 microprocessor
Answer :
Features of 8085: 1. 16 address line so 216=64 Kbytes of memory can be addressed. 2. Operating clock frequency is 3MHz and minimum clock frequency is 500 KHz. 3. On chip bus controller ... duty cycle TTL clock 10. Provide 2 serial I/O lines, so peripheral can be interfaced with 8085 μp
asked
Jul 31, 2019
by
anonymous
Description : State any four salient features of turbo- alternator.
Answer :
Special features of a turbo alternator used in TPS: Special Futures (Highlights): It is 3-phase generator. A separate excitation is given to alternator by DC generator ( ... under voltage protection. Over frequency under frequency protection. Over load protection. Over temperature protection
asked
Sep 8, 2018
by
anonymous
Description : List out any four salient features of hydro generator.
Answer :
Following are the salient features of a Hydro Generator (alternator): It is 3-ph hydro generator (alternator). It is robust in construction. A separate excitation is given to ... & under frequency protection, 5. Over temperature protection are main protections provided to generator.
asked
Sep 7, 2018
by
anonymous
Description : Is the speed of alternator is directly proportional to frequency?
Answer :
Yes, speed of alternator is directly proportional to frequency.
asked
Mar 18, 2018
by
anonymous
Description : In dc machines, the armature windings are placed on the rotor because of the necessity for (1) electromechanical energy conversion (2) generation of voltage (3) commutation (4) development of torque
Answer :
3 Commutation
asked
May 1, 2018
by
anonymous
Description : Ratio of the rotor reactance X to the rotor resistance R for a two-phase servo motor (A) is equal to that of a normal induction motor (B) is less than that of a normal induction motor (C) is greater than that of a normal induction motor (D) may be less or greater than that of a normal induction motor
Answer :
C
asked
Apr 28, 2018
by
anonymous
Answer :
The shaded pole motor is used for low starting torque.
asked
Mar 20, 2018
by
anonymous
Answer :
A shaded pole motor can be used for toys, hair dryers, circulators etc.
asked
Mar 20, 2018
by
anonymous
Answer :
The range of efficiency for shaded pole motors is 5% to 35%.
asked
Mar 20, 2018
by
anonymous
Description : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm
Answer :
The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min 200 rpm
asked
Apr 28, 2018
by
anonymous
Description : The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?
Answer :
Ns equals f/pair pole 50/4 - 12.5
asked
Dec 31, 2017
by
anonymous
Description : Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.
asked
Apr 16, 2020
by
anonymous
Description : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be
Answer :
The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be 0.5 Ohm
asked
May 3, 2018
by
anonymous
Answer :
The bearings used to support the rotor shafts are generally ball bearings.
asked
Mar 20, 2018
by
anonymous
Answer :
The rotor of a hysteresis motor is made of chrome steel.
asked
Mar 20, 2018
by
anonymous
Answer :
In a hysteresis motor, the rotor must have retentivity.
asked
Mar 20, 2018
by
anonymous
Answer :
The rotor developed by a single-phase motor at starting is zero.
asked
Mar 20, 2018
by
anonymous
Description : What is the rotor of a motor?
Answer :
Rotor is the rotating or moving part in motor and generator.
asked
Dec 16, 2017
by
anonymous
Description : With a neat sketch give the working of shaded pole induction motor.
Answer :
Explanation: It has squirrel cage rotor and salient pole stator. The stator poles are shaded partially by short circuited conductor band to create the phase difference between the fluxes emerging from shaded ... rotating magnetic field in the air-gap and torque is exerted on the squirrel cage rotor.
asked
Apr 27, 2020
by
anonymous
Description : State two applications of 1) Shaded pole motor 2) Universal motor
Answer :
(i)Applications of Shaded pole motor: 1. Small fans 2. Toy motors 3. Hair dryers 4. Ventilators 5. Electric clocks 6. Record players 7. Motorized valves 8. Gramophones 9. Photocopying ... 5. Portable Drilling Machines 6. Electric Shavers 7. Mechanical computing Machines 8. Machine Tools etc.
asked
Jul 26, 2019
by
anonymous
Description : A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is
Answer :
A 50 Hz, 4 pole turboalternator rated at 20 MVA. 13.2 KV has an inertia constant H = 4 KW sec/KVA. The K.E. stored in the rotor at synchronous speed is 80 MJ
asked
May 3, 2018
by
anonymous
Answer :
In case of a shaded pole motor the direction of rotation of the motor is from main pole to shaded pole.
asked
Mar 20, 2018
by
anonymous
Answer :
In a shaded pole motor, the shading coil usually consist of a single turn of heavy copper wire which is short-circuited and carries only induced current.
asked
Mar 20, 2018
by
anonymous
Answer :
The torque produced in induction type relay (shaded pole structure) is inversely proportional to the square of the current.
asked
Mar 20, 2018
by
anonymous
Description : Explain MOSFET gate drive circuit and totem pole configuration.
Answer :
MOSFET gate drive circuit: The turning on and turning off of MOSFET can be controlled from gate to source voltage signal. If the gate to source voltage of MOSFET exceeds threshold ... this configuration, the two switches (transistors) are used in totem pole arrangement with a comparator.
asked
Feb 19, 2018
by
anonymous
Answer :
For constant torque drive armature voltage control speed control method is preferred.
asked
Mar 20, 2018
by
anonymous
Answer :
For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.
asked
Mar 20, 2018
by
anonymous
Answer :
The speed control of universal motor used for sewing machines is by varying the resistance.
asked
Mar 20, 2018
by
anonymous
Answer :
The stator of phase shifting transformer for use in conjunction with an A.C. potentiometer usually has a two-phase winding.
asked
Mar 21, 2018
by
anonymous
Description : Can I use C++ for Arduino?
Description : Can you use Python for Arduino?
asked
Mar 10, 2018
by
anonymous
Description : The number of cycles in which a high speed circuit breaker can complete its operation is (A) 3 to 8 (B) 10 to 18 (C) 20 to 30 (D) 40 to 50
Answer :
The number of cycles in which a high speed circuit breaker can complete its operation is 3 to 8
asked
May 8, 2018
by
anonymous
Description : In an adjustable speed ac drive which quantity gets reduced above rated speed ? (A) developed torque (B) stator frequency (C) reduced starting torque (D) stator current
Answer :
In an adjustable speed ac drive which quantity gets reduced above rated speed ? (A) developed torque (B) stator frequency (C) reduced starting torque (D) stator current
asked
Apr 28, 2018
by
anonymous
Answer :
Series motor has the poorest speed control.
asked
Mar 20, 2018
by
anonymous
Description : Synchronous motor always runs at which speed?
Answer :
Synchronous motor always runs at synchronous speed.
asked
Mar 18, 2018
by
anonymous
Description : Which motor has the best speed regulation?
asked
Mar 15, 2018
by
anonymous
Answer :
Discrimination between main and back up protection is provided by the use of relays which are slow.
asked
Mar 20, 2018
by
anonymous
Description : The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?
Answer :
The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.
asked
Mar 20, 2018
by
anonymous
Description : Define Feed and speed in shaping machine
Answer :
1) Feed: Feed (S) is the relative movement of the work or tool in a direction perpendicular to the axis of reciprocation of the ram per double stroke. It is expressed in mm per stroke. 2) Speed: ... speed is the speed at which the metal is removed by the cutting tool in a period of one minute.
asked
May 7, 2020
by
anonymous
Description : Speed control of the motor using TRIAC
Answer :
Speed control of the motor using TRIAC: This basic phase triggering circuit uses the triac in series with the motor across an AC sinusoidal supply. The variable resistor, VR1 is used ... meaning that it may not trigger at the exact same point for each positive and negative half cycle.
asked
Oct 13, 2019
by
anonymous
Description : Why does the speed of a DC shunt motor decrease as the load increases?
Answer :
Because if the load is increasing then the torque must also be increase. If not then the speed of motor will decrease.
asked
Jul 5, 2019
by
anonymous
Description : Describe the following errors and their compensation: (i) Phase error (ii) Speed error
Answer :
(I) Phase error 1. In the phase error the phase difference angle between ∅ & ∅ is kept by using the shading band/ring 2. If the design and location of Shading band/ring is ... of brake magnet. By changing the position of the brake magnet speed of the rotating disc can be controlled.
asked
Sep 6, 2018
by
anonymous