Why starter is necessary to start the AC motor?

Why starter is necessary to start the AC motor?
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1 Answer

Answer :

a. At the time of starting motor starting current is high (4 to 5 times). Therefore if motor is directly started the supply voltage may be disturb. b. By the help of starters starting and stopping of motors can be made easily as we required. Because starters provides overload tripping difficulties. c. The help of starters can protect motor against the single phasing by the action of overload arrangements. d. Protect the motor from no-voltage and its difficulties. e. Permits automatic control when required.
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Related questions

To check the three line fuses of a three-phase system consisting of a three-phase motor, you must _____________. A. place the starter in the 'stop' position B. make sure the motor is operating at full load to guard against a false reading C. place the leads across the 'hot' ends of the fuses D. place the leads across the bottom ends of the fuses

Description : To check the three line fuses of a three-phase system consisting of a three-phase motor, you must _____________. A. place the starter in the 'stop' position B. make sure the motor is operating at full ... leads across the 'hot' ends of the fuses D. place the leads across the bottom ends of the fuses

Last Answer : Answer: A

Motor starter or controller contacts may become welded together if the contacts _____________. A. open too quickly and arc B. close under excessive pressure C. open or close too quickly D. close under excessive starting current

Description : Motor starter or controller contacts may become welded together if the contacts _____________. A. open too quickly and arc B. close under excessive pressure C. open or close too quickly D. close under excessive starting current

Last Answer : Answer: D

Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The starter must be placed in the STOP position to stop the motor. C. The three line connections in the motor terminal box must be disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.

Description : Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The ... disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.

Last Answer : Answer: B

Motor controller or starter contacts may become pitted and welded together if the contacts _____________. A. open under loaded conditions B. close slowly with light pressure C. open too quickly and arc D. close quickly with proportionate pressure

Description : Motor controller or starter contacts may become pitted and welded together if the contacts _____________. A. open under loaded conditions B. close slowly with light pressure C. open too quickly and arc D. close quickly with proportionate pressure

Last Answer : Answer: B

Excessive heat in an operating motor controller can result from _____________. A. a closed starter contact B. loose connections C. missing arc chutes D. low motor starting torque

Description : Excessive heat in an operating motor controller can result from _____________. A. a closed starter contact B. loose connections C. missing arc chutes D. low motor starting torque

Last Answer : Answer: B

If the contacts of a motor starter or controller fail to drop out when the 'stop' button is depressed the ____________. A. contacts are carrying excessive current B. contacts have become welded together C. shading coil is broken D. shading coil is loose

Description : If the contacts of a motor starter or controller fail to drop out when the 'stop' button is depressed the ____________. A. contacts are carrying excessive current B. contacts have become welded together C. shading coil is broken D. shading coil is loose

Last Answer : Answer: B

Low voltage releases as used in some shipboard motor starter and control equipment will have which of the following characteristics? A. They trip circuit contactors when the motor starts to overspeed. B. They require manual resetting upon restoration of normal voltage. C. They use a phase sensitive relay to trip contacts in series with the holding coil of the starter. D. They allow the motor to restart upon restoration of normal voltage.

Description : Low voltage releases as used in some shipboard motor starter and control equipment will have which of the following characteristics? A. They trip circuit contactors when the motor starts to overspeed. B. ... coil of the starter. D. They allow the motor to restart upon restoration of normal voltage.

Last Answer : Answer: D

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Last Answer : Answer: D

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Description : The rotor slots of a repulsion-type motor are generally skewed (placed nonparallel to the rotor axis) to _________. A. produce a constant starting torque B. permit a greater air gap with the starter C. permit a smaller air gap with the starter D. reduce eddy current losses

Last Answer : Answer: A

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Description : The diagram shown in the illustration represents a _________. EL-0058 A. dual speed, 2-winding motor controller B. navigation running light circuit C. single phase, 2-motor selectable starter D. common fluorescent lighting circuit

Last Answer : Answer: B

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Description : What is the Necessity of Starter of an Induction Motor?

Last Answer : Induction motors, when direct-switched, take five to seven times their full-load current and develop only 1.5 to 2.5 times their full-load torque. This initial excessive current is ... electrical equipment connected to the same lines. Hence, a starter is necessary to overcome this objection.

What are the types of DC motor starter?

Description : What are the types of DC motor starter?

Last Answer : a. DC two point starter for series motor. b. DC three point starter for shunt motor. c. DC four point starter for compound motor.

What is the necessity of DC motor starter?

Description : What is the necessity of DC motor starter?

Last Answer : Eb = V - Ia ra. ∴ Ia = V - Eb / ra. At the time of starting from the rest there is no any back emf (Eb) in the armature. So a large current flows through the armature based on ... develops back emf (Eb) which regulates it's speed and armature current. This can be achieved by the help of starter.

What are the advantages of star-delta starter with induction motor?

Description : What are the advantages of star-delta starter with induction motor?

Last Answer : The main advantage of using the star delta starter is reduction of current during the starting of the motor. Starting current is reduced to 3-4 times of current of Direct online starting Hence the starting current is reduced , the voltage drops during the starting of motor in systems are reduced

Why star delta starter is preferred with induction motor?

Description : Why star delta starter is preferred with induction motor?

Last Answer : Star delta starter is preferred with induction motor due to following reasons: Starting current is reduced 3-4 times of the direct current due to which voltage drops and hence it causes less ... caused. In addition, starting torque is increased and it prevents the damage of motor winding.

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Description : How do you start a motor without a starter?

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Description : When an AC or a DC motor fails to start, the FIRST step in troubleshooting should be to check the ____________. A. motor windings for obvious opens B. motor controller leads for continuity C. fuse or circuit breaker D. motor controller leads for grounds

Last Answer : Answer: C

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Description : In the illustrated ground detection system with a ground on phase A, if the switch is opened __________. EL-0009 A. lamp A will dim or go out depending on the severity of the ground B. all three ... lamp A will be brighter D. lamp A will start flickering if the ground is in an AC induction motor

Last Answer : Answer: B

Which type of AC single-phase motor will also operate on direct current? A. Split-phase B. Series-wound C. Shaded-pole D. Repulsion-start

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Last Answer : Answer: B

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Description : Where is the starter motor on a xsara Picasso 1.6 petrol?

Last Answer : Need answer

Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.

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Last Answer : Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter

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Description : Develop the control circuit for star-delta starter used for starting a 3 ∅ induction motor.

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State the function of overload coil and No volt coil in dc motor starter.

Description : State the function of overload coil and No volt coil in dc motor starter.

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Description : Draw and explain star delta starter for 3 phase induction motor

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Explain DOL starter used for 3 phase induction motor.

Description : Explain DOL starter used for 3 phase induction motor.

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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.

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Draw the power and control circuit diagram for forward — stop — Reverse type DOL starter for 3 phase induction motor.

Description : Draw the power and control circuit diagram for forward — stop — Reverse type DOL starter for 3 phase induction motor.

Last Answer : Draw the power and control circuit diagram for forward — stop — Reverse type DOL starter for 3 phase induction motor.

Describe the power and control circuit for automatic Star-Delta starter for 3-phase induction motor.

Description : Describe the power and control circuit for automatic Star-Delta starter for 3-phase induction motor.

Last Answer : Power circuit: Control circuit: 

A 3-phase delta connected squirrel cage induction motor when started with a DOL starter has a starting

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Description : Consider the following statements: Star delta starter is used in 3-phase induction motor because it  1. Prevents heating of the motor winding  2. Ensures permissible minimum starting current  3. Is regulated by electricity ... and 4 are correct (c) 1, 3 and 4 are correct (d) 1 and 2 are correct 

Last Answer : Consider the following statements: Star delta starter is used in 3-phase induction motor because it  1. Prevents heating of the motor winding  2. Ensures permissible minimum starting current  3. Is regulated by ... and 4 are correct (c) 1, 3 and 4 are correct (d) 1 and 2 are correct 

The coils of D.C. motor starter are wound with wire of?

Description : The coils of D.C. motor starter are wound with wire of?

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In a manual shunt motor starter?

Last Answer : In a manual shunt motor starter over load relay is connected in series and no volt relay in parallel with the load.

For starting a D.C. motor a starter is required because?

Last Answer : For starting a D.C. motor a starter is required because it limits the starting current to a safe value.

The electrical schematic shown in the illustration represents a/an ____________. EL-0017 A. across-the-line starter B. primary-resistor starter C. autotransformer starter D. part-winding starter

Description : The electrical schematic shown in the illustration represents a/an ____________. EL-0017 A. across-the-line starter B. primary-resistor starter C. autotransformer starter D. part-winding starter

Last Answer : Answer: A

When a fluorescent lamp fails to light, the trouble can be in the _____________. A. lamp B. starter C. ballast D. all of the above

Description : When a fluorescent lamp fails to light, the trouble can be in the _____________. A. lamp B. starter C. ballast D. all of the above

Last Answer : Answer: D

When a fluorescent lamp has reached the end of its useful life, it should be replaced immediately, or the resultant flashing may _____________. A. blow the lamp's circuit breaker B. explode, causing glass to fly in all directions C. short circuit the ballast transformer D. damage the starter and the ballast

Description : When a fluorescent lamp has reached the end of its useful life, it should be replaced immediately, or the resultant flashing may _____________. A. blow the lamp's circuit breaker B. explode, ... fly in all directions C. short circuit the ballast transformer D. damage the starter and the ballast

Last Answer : Answer: D

An across-the-line starter provides ___________________. A. maximum torque B. slow starting power C. high speed D. reduced voltage

Description : An across-the-line starter provides ___________________. A. maximum torque B. slow starting power C. high speed D. reduced voltage

Last Answer : Answer: A

Which of the following components are used to assemble a fluorescent lighting system? A. Lamp B. Starter C. Ballast D. All of the above

Description : Which of the following components are used to assemble a fluorescent lighting system? A. Lamp B. Starter C. Ballast D. All of the above

Last Answer : Answer: D

An across-the-line starter is typically used for which of the following applications? A. Reduced-current starting of large motors B. Low torque starting of small motors C. Low resistance starting of DC motors D. Full-voltage starting of motors

Description : An across-the-line starter is typically used for which of the following applications? A. Reduced-current starting of large motors B. Low torque starting of small motors C. Low resistance starting of DC motors D. Full-voltage starting of motors

Last Answer : Answer: D

Which component of the circuit shown in the illustration is the starter? EL-0081 A. A B. B C. C D. D

Description : Which component of the circuit shown in the illustration is the starter? EL-0081 A. A B. B C. C D. D

Last Answer : Answer: B

Difference Between A Four Point Starter And Three Point Starter?

Description : Difference Between A Four Point Starter And Three Point Starter?

Last Answer : The shunt connection in four point stater is provided separately form the line where as in three point stater it is connected with line which is the drawback in three point stater.

What is the necessity of starter?

Description : What is the necessity of starter?

Last Answer : Its function is to reduce starting current and also provide protection against over load and over voltage.

What is the purpose of static starter? How current setting adopted?

Description : What is the purpose of static starter? How current setting adopted?

Last Answer : The static starter limits the starting current of the motor to 2.5 times the motor rated current instead of 6 times the rated current. If the motor is directly on UPS, the UPS fuse will blow, ... set to limit the starting current. This is achieved by firing angle control of back to back thyristor. 

Based on what factors will you select rating of components for a starter cell?

Description : Based on what factors will you select rating of components for a starter cell?  

Last Answer : Factors for selecting rating of components are, a. Capacity of load. b. Type of starting. c. Duty (continuous or intermittent). d. Type of protection. e. Nature of starting (acceleration time is slow or fast). 

Difference between a four point starter and three point starters?

Description : Difference between a four point starter and three point starters?

Last Answer : The shunt connection in four point starter is provided separately from the line where as in three point starter it is connected with line which is the drawback in three point starter

If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller circuitry illustrated? EL-0011 A. 110 volts DC B. 110 volts AC C. 220 volts DC D. 220 volts AC

Description : If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller circuitry illustrated? EL-0011 A. 110 volts DC B. 110 volts AC C. 220 volts DC D. 220 volts AC

Last Answer : Answer: D

The energy consumed by an AC motor, as strictly reactive power, is _____________. A. used to do mechanical work B. used to establish the magnetic field of the motor C. lost as heat generated by the windings D. lost in doing work to turn the motor itself

Description : The energy consumed by an AC motor, as strictly reactive power, is _____________. A. used to do mechanical work B. used to establish the magnetic field of the motor C. lost as heat generated by the windings D. lost in doing work to turn the motor itself

Last Answer : Answer: B

The most practical method of controlling the RPM of a step-speed AC motor is to _____________. A. change input voltage B. vary the number of poles C. vary power factor D. change the number of brushes

Description : The most practical method of controlling the RPM of a step-speed AC motor is to _____________. A. change input voltage B. vary the number of poles C. vary power factor D. change the number of brushes

Last Answer : Answer: B

The prime mover of an AC two pole main propulsion generator drives the generator at 3600 RPM. If the main propulsion motor has 80 poles, what will be the propeller speed? A. 45 RPM B. 80 RPM C. 90 RPM D. 180 RPM

Description : The prime mover of an AC two pole main propulsion generator drives the generator at 3600 RPM. If the main propulsion motor has 80 poles, what will be the propeller speed? A. 45 RPM B. 80 RPM C. 90 RPM D. 180 RPM

Last Answer : Answer: C