How cooling is done for slip ring and brush gear?

How cooling is done for slip ring and brush gear? 
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1 Answer

Answer :

A centrifuge fan is mounted on the shaft in between two slip rings for ventilation of the slip rings and brush gear.
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Related questions

Which of the following statements represents the FIRST step in seating new brushes on slip rings? A. Wrap sandpaper around the slip rings and slide it back and forth between the brushes and the slip rings. B. Press the brushes against the slip ring with a wood block. C. Increase brush pressure and run at no load for 3 to 4 hours. D. Apply seating compound under the brushes and run at no load for 2 hours.

Description : Which of the following statements represents the FIRST step in seating new brushes on slip rings? A. Wrap sandpaper around the slip rings and slide it back and forth between the brushes and the slip rings. B. ... to 4 hours. D. Apply seating compound under the brushes and run at no load for 2 hours.

Last Answer : Answer: A

What is the type of brush used in brush gear?

Description : What is the type of brush used in brush gear?

Last Answer : Low co-efficient of friction and self-lubricating morganite grade carbon HM100. Now a day we are using LFC554 for economical reasons. 

Chattering of the collector ring brushes on a generator may be remedied by _____________. A. lubricating brush holders B. reinsulating the brushes C. cleaning the collector rings D. increasing length of pigtail

Description : Chattering of the collector ring brushes on a generator may be remedied by _____________. A. lubricating brush holders B. reinsulating the brushes C. cleaning the collector rings D. increasing length of pigtail

Last Answer : Answer: C

If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring

Description : If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring

Last Answer : Answer: A

A degree of control over the speed of a slip ring induction motor can be obtained by _____________. A. adjusting governor linkage B. changing the number of phases to the motor C. inserting resistance into the stator circuit D. inserting resistance into the rotor circuit

Description : A degree of control over the speed of a slip ring induction motor can be obtained by _____________. A. adjusting governor linkage B. changing the number of phases to the motor C. inserting resistance into the stator circuit D. inserting resistance into the rotor circuit

Last Answer : Answer: D

Slip ring induction motor advantages and disadvantages compared to squirrel cage motors?

Description : Slip ring induction motor advantages and disadvantages compared to squirrel cage motors?

Last Answer : Advantages: High starting torque with low starting current Smooth acceleration under heavy loads No abnormal heating during starting Good running characteristics after external rotor resistances are cut out ... cage motors The speed regulation is poor when run with resistance in the rotor circuit

Mention different types of speed control of slip ring induction motor?

Description : Mention different types of speed control of slip ring induction motor?

Last Answer : a) By changing supply frequency b) By changing the number of stator poles c) By rotor rheostat control d) By operating two motors in cascade

How the slip ring motor is started?

Description : How the slip ring motor is started?

Last Answer : The slip ring motor is started by using rotor resistance starter. The starter consists of star connected resistance to slip rings. While starting the full resistance is included in the rotor circuit to ... running condition the slip rings are shorted and so it is equivalent to squirrel cage rotor.

What are the advantages of slip ring motor over squirrel cage motor?

Description : What are the advantages of slip ring motor over squirrel cage motor?

Last Answer : 1. The starting torque can be varied by adding resistance to rotor. 2. The speed of the machine can be varied by injecting an emf through slip rings to the rotor.

What is the purpose of connecting external resistors to slip ring Induction motor?

Description : What is the purpose of connecting external resistors to slip ring Induction motor?

Last Answer : It increases starting torque and decreases starting current.

What is the material of slip ring?

Description : What is the material of slip ring? 

Last Answer : Alloy steel  

Where is a slip ring used and where is a commutator used?

Description : Where is a slip ring used and where is a commutator used?

Last Answer : Slip rings are commonly found in slip ring motors, electrical generators for alternating current systems and alternators. They can be used on any rotating object to transfer power. A commutator is a common ... in the moving coil of a motor's armature, a steady rotating force (torque) is produced.

Which component is mainly used in a DC generator: a.slip ring b. commutator c. magnet d. coil

Description : Which component is mainly used in a DC generator: a.slip ring b. commutator c. magnet d. coil

Last Answer : b. commutator

Which one is not present in AC generator: a. Armature b. magnet c. slip ring d. commutator

Description : Which one is not present in AC generator: a. Armature b. magnet c. slip ring d. commutator

Last Answer : c. slip ring

State the function of following parts of slip ring induction motor: (i) Slip ring (ii) Fan (iii) Brushes (iv) Frame

Description : State the function of following parts of slip ring induction motor: (i) Slip ring (ii) Fan (iii) Brushes (iv) Frame

Last Answer : Sr. No. Name of part Function 1 Slip ring 1) The rotor winding terminals are permanently connected to the slip rings. 2) Connects external resistance to rotor circuit through ... It provides mechanical support to the entire internal parts of motor. 2) Protects the inner parts.

Compare squirrel cage induction motor and slip ring induction motor any four points.

Description : Compare squirrel cage induction motor and slip ring induction motor any four points.

Last Answer : Comparison Between Squirrel Cage Induction Motor and Slip Ring Induction Motor: Sr. No. Squirrel Cage Induction Motor Slip Ring Induction Motor 1 Rotor is in the form of short circuited bars ... drive e.g. Lathe machine. Used where high starting torque is required e.g. Lifts.

Develop power and control diagram for secondary frequency acceleration starter of slip ring induction motor.

Description : Develop power and control diagram for secondary frequency acceleration starter of slip ring induction motor. 

Last Answer : Power and Control Circuit diagram for secondary frequency acceleration starter of slip ring induction motor:

Draw power and control circuit for definite time-limit starter for slip-ring induction motor. Explain its working.

Description : Draw power and control circuit for definite time-limit starter for slip-ring induction motor. Explain its working.

Last Answer : Definite Time-limit Starter for Slip-ring Induction Motor: This starter is used for automatic control of acceleration of slip-ring induction motor at the time of starting. In this starter, the ... each phase, shorting the rotor winding terminals and final acceleration of the motor takes place. 

The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open

Description : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the ... frequency of induced voltage across slip ring is A) 30 Hz B) 70 Hz C) 20 Hz D) 35 Hz

Last Answer : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is 70 Hz

A three phase slip ring induction motor is fed from the rotor side with stator winding short circuited stator is:

Description : A three phase slip ring induction motor is fed from the rotor side with stator winding short circuited stator is: (1) Slip frequency (2) Supply frequency (3) Frequency corresponding to rotor speed (4) Zero

Last Answer : A three phase slip ring induction motor is fed from the rotor side with stator winding short circuited stator is: Slip frequency

A three phase slip ring induction motor with chopper controlled resistance has its torque

Description : A three phase slip ring induction motor with chopper controlled resistance has its torque proportional to   (a) Rotor current (b) Stator resistance (c) Square of rotor current (d) Square root of rotor current 

Last Answer : A three phase slip ring induction motor with chopper controlled resistance has its torque proportional to Square of rotor current

The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted

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

Last 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

In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an

Description : In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is (A) 0.2 Ω (B) 0.3 Ω (C) 0.4 Ω (D) 0.5 Ω

Last Answer : In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is 0.3 Ω

How selection of cooling fluid in GT done?

Description : How selection of cooling fluid in GT done? 

Last Answer : a) There are 5 factors are there. b) Density c) Coefficient of thermal expansion d) Viscosity e) Specific heat f) Thermal conductivity. 

Due to which of the following factors the brush wear rate is altered ? (a) Speed of the machine (b) Contact pressure (c) Surface conditions of brush and commutator (d) Excessive sparking (e) All of the above

Description : Due to which of the following factors the brush wear rate is altered ? (a) Speed of the machine (b) Contact pressure (c) Surface conditions of brush and commutator (d) Excessive sparking (e) All of the above

Last Answer : Ans: E

Sparking at the brushes of a DC propulsion motor can be the result of ____________. A. improper brush pressure B. improper brush seating C. reversed interpole polarity D. all of the above

Description : Sparking at the brushes of a DC propulsion motor can be the result of ____________. A. improper brush pressure B. improper brush seating C. reversed interpole polarity D. all of the above

Last Answer : Answer: D

If only one brush on a commutator is sparking excessively, you should look for _____________. A. a high commutator bar B. copper imbedded in the brush C. a loose commutator bar D. flux in the commutating zone

Description : If only one brush on a commutator is sparking excessively, you should look for _____________. A. a high commutator bar B. copper imbedded in the brush C. a loose commutator bar D. flux in the commutating zone

Last Answer : Answer: B

Uneven wear of the commutator surface on a direct current propulsion motor can be caused by _____________. A. rapid change in load B. excessive operation at light load C. incorrect brush staggering D. unequal pole spacing

Description : Uneven wear of the commutator surface on a direct current propulsion motor can be caused by _____________. A. rapid change in load B. excessive operation at light load C. incorrect brush staggering D. unequal pole spacing

Last Answer : Answer: C

Sparking at the brushes of a running motor could be an indication of _____________. A. normal operation B. a dirty commutator C. increased brush capacity D. water vapor absorption

Description : Sparking at the brushes of a running motor could be an indication of _____________. A. normal operation B. a dirty commutator C. increased brush capacity D. water vapor absorption

Last Answer : Answer: B

If a D.C. motor hums, but does not run when energized, which of the listed conditions could exist? A. Incorrect lead connections B. Incorrect brush setting C. A dirty commutator D. All of the above are correct.

Description : If a D.C. motor hums, but does not run when energized, which of the listed conditions could exist? A. Incorrect lead connections B. Incorrect brush setting C. A dirty commutator D. All of the above are correct.

Last Answer : Answer: D

The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Last Answer : Answer: C

Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Last Answer : Answer: D

A three-phase, squirrel cage, induction motor will run hot due to a/an ______________. A. improper brush position B. reversed commutating pole C. shorted stator D. high power factor

Description : A three-phase, squirrel cage, induction motor will run hot due to a/an ______________. A. improper brush position B. reversed commutating pole C. shorted stator D. high power factor

Last Answer : Answer: C

D.C. propulsion motor brush pressure depends on the brush grade used and in practice is set with a ______________. A. multimeter B. manometer C. spring scale D. compound gauge

Description : D.C. propulsion motor brush pressure depends on the brush grade used and in practice is set with a ______________. A. multimeter B. manometer C. spring scale D. compound gauge

Last Answer : Answer: C

One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Description : One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Last Answer : Answer: D

One of the generator or motor bearings is generally insulated from the end housing in order to prevent ________. A. rapid brush wear B. current leakage from the shaft C. excessive field winding heat D. circulation of shaft currents induced in the machine's frame

Description : One of the generator or motor bearings is generally insulated from the end housing in order to prevent ________. A. rapid brush wear B. current leakage from the shaft C. excessive field winding heat D. circulation of shaft currents induced in the machine's frame

Last Answer : Answer: D

D.C. motor brush adjustment includes attention to _________. A. angle with the commutator and clearance within the holder B. brush length and pigtail tightness C. grade of material and surface dirt conditions D. all of the above

Description : D.C. motor brush adjustment includes attention to _________. A. angle with the commutator and clearance within the holder B. brush length and pigtail tightness C. grade of material and surface dirt conditions D. all of the above

Last Answer : Answer: D

Propulsion DC motor brush pressures can be calculated by _____________. A. dividing the brush contact area by the spring pressure B. subtracting the brush contact area from the spring pressure C. dividing the spring force by the brush contact area D. subtracting the spring pressure from the brush contact area

Description : Propulsion DC motor brush pressures can be calculated by _____________. A. dividing the brush contact area by the spring pressure B. subtracting the brush contact area from the spring pressure C. ... force by the brush contact area D. subtracting the spring pressure from the brush contact area

Last Answer : Answer: C

In general, D.C. propulsion motor brush sparking can be caused by _______________. A. incorrect brush grade, pressure or position B. a concentric commutator C. a dark chocolate colored commutator D. all of the above

Description : In general, D.C. propulsion motor brush sparking can be caused by _______________. A. incorrect brush grade, pressure or position B. a concentric commutator C. a dark chocolate colored commutator D. all of the above

Last Answer : Answer: A

The direction of rotation of a DC propulsion motor can be changed by reversing the _____________. A. brush holder position B. polarity of the field poles C. brush staggered order D. motor interpole connections

Description : The direction of rotation of a DC propulsion motor can be changed by reversing the _____________. A. brush holder position B. polarity of the field poles C. brush staggered order D. motor interpole connections

Last Answer : Answer: B

The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Last Answer : Answer: C

In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings

Description : In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings

Last Answer : Answer: A

A commutator's protective oxide film can be destroyed by _________________. A. periods of low humidity B. very low brush current density C. improper brush grade D. all of the above

Description : A commutator's protective oxide film can be destroyed by _________________. A. periods of low humidity B. very low brush current density C. improper brush grade D. all of the above

Last Answer : Answer: D

An important factor in reducing D.C. motor commutator wear is _______________. A. keeping the ambient humidity as low as possible B. ensuring a very low brush current density C. establishing the copper oxide surface film D. all of the above

Description : An important factor in reducing D.C. motor commutator wear is _______________. A. keeping the ambient humidity as low as possible B. ensuring a very low brush current density C. establishing the copper oxide surface film D. all of the above

Last Answer : Answer: C

Grease coatings on electrical contact surfaces increase contact resistance and should be removed with a/an _______________. A. small wire brush B. compressed air jet C. clean dry cloth D. 10% solution carbon solvent and water

Description : Grease coatings on electrical contact surfaces increase contact resistance and should be removed with a/an _______________. A. small wire brush B. compressed air jet C. clean dry cloth D. 10% solution carbon solvent and water

Last Answer : Answer: C

Insufficient brush pressure on a DC motor may cause _______. A. generator overload B. excess residual magnetism C. water vapor absorption D. sparking of the brushes

Description : Insufficient brush pressure on a DC motor may cause _______. A. generator overload B. excess residual magnetism C. water vapor absorption D. sparking of the brushes

Last Answer : Answer: D

The item referred to as a pigtail on a DC motor brush rigging is a/an ______________. A. feather spring B. uninsulated wire C. flexible spring adjuster D. brush holder

Description : The item referred to as a pigtail on a DC motor brush rigging is a/an ______________. A. feather spring B. uninsulated wire C. flexible spring adjuster D. brush holder

Last Answer : Answer: B

Which of the following statements is true concerning the cleaning of electrical contacts? A. Compressed air should be used to blow out metallic dust. B. Magnetic brushes should be used to remove metallic dust. C. The contact surfaces should be greased to increase contact resistance. D. Delicate parts should be cleaned with a brush and an approved safety solvent.

Description : Which of the following statements is true concerning the cleaning of electrical contacts? A. Compressed air should be used to blow out metallic dust. B. Magnetic brushes should be used to remove ... contact resistance. D. Delicate parts should be cleaned with a brush and an approved safety solvent.

Last Answer : Answer: D

The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values _____________. A. immediately after shutting down the machine B. every time the brush rigging is adjusted C. immediately after starting up the machine D. every 30 days whether the machine is in use or not

Description : The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values _____________. A. immediately after shutting down the machine B. every time the brush rigging is ... starting up the machine D. every 30 days whether the machine is in use or not

Last Answer : Answer: A