menu search
person

How is a three phase cage induction motor self starting?

thumb_up_alt 0 like thumb_down_alt 0 dislike
104 views

1 Answer

Any type of induction motor is self starting.

Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if theta is varying then torqe also pulsating.

In induction motor this angle theta is not pulsating.so it is self starting 
thumb_up_alt 0 like thumb_down_alt 0 dislike
← Prev Question Next Question →

Related questions

Description :

In a double squirrel cage induction motor, good starting torque is produced as (A) Large current flows through the outer high resistance winding. (B) Large current flows through the inner high resistance winding. (C) Small current flows through the outer high resistance winding. (D) Large current flows through the inner low resistance winding.

Answer :

In a double squirrel cage induction motor, good starting torque is produced as Large current flows through the outer high resistance winding.

thumb_up_alt 0 like thumb_down_alt 0 dislike
98 views 1 answer
Description :

Is induction motor is self starting?

Answer :

Single phase induction motor is not self starting. Three phase induction motor is self starting.

thumb_up_alt 0 like thumb_down_alt 0 dislike
97 views 1 answer
Description :

List different starting methods of three phase synchronous motor. Explain any one of them.

Answer :

Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor. 

thumb_up_alt 0 like thumb_down_alt 0 dislike
77 views 1 answer
Description :

The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 

Answer :

The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent

thumb_up_alt 0 like thumb_down_alt 0 dislike
217 views 1 answer
Description :

What is mean by plugging in three phase induction motor?

Answer :

Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.

thumb_up_alt 0 like thumb_down_alt 0 dislike
130 views 1 answer
Description :

how can we reverse the direction of rotation of three phase induction motor ?

Answer :

The direction of rotation of three phase induction motor can be reversed by plugging i.e by changing any two out of three phases of the supply to the stator of the Induction motor terminal.

thumb_up_alt 1 like thumb_down_alt 0 dislike
108 views 1 answer
Description :

Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.

thumb_up_alt 0 like thumb_down_alt 0 dislike
94 views 0 answers
Description :

Explain the need and steps to conduct the reduced voltage running up test on the three phase induction motor.

thumb_up_alt 0 like thumb_down_alt 0 dislike
64 views 0 answers
Description :

State any four advantages of three phase induction motor. 

Answer :

Advantages of three phase induction motor https://youtu.be/27OIOCKN05U

thumb_up_alt 0 like thumb_down_alt 0 dislike
110 views 2 answers
Description :

Answer :

If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.

thumb_up_alt 0 like thumb_down_alt 0 dislike
205 views 1 answer
Description :

Answer :

Capacitor start motor has high torque in starting

thumb_up_alt 0 like thumb_down_alt 0 dislike
97 views 1 answer
Description :

A synchronous motor can be made self starting by providing?

Answer :

A synchronous motor can be made self-starting by providing damper bar.

thumb_up_alt 0 like thumb_down_alt 0 dislike
111 views 1 answer
Description :

State starters used for i) 3-Ph squirrel cage induction motor (3HP) ii) D.C. motor 

Answer :

Name the starters used for following motors : i) 3 H.P. 3-Ph squirrel cage I.M: i) DOL starter OR ii) Star-Delta Starter OR ii) Auto transformer starter OR iii) Soft start starter.  ii) D.C Shunt Motor : 1) Armature resistance starter (Three Point Starter) OR 2) Four Point Starter 

thumb_up_alt 0 like thumb_down_alt 0 dislike
125 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
152 views 2 answers
Description :

Answer :

Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.

thumb_up_alt 0 like thumb_down_alt 0 dislike
177 views 1 answer
Description :

speed control methods of three phase induction motor?

Answer :

Speed control of three phase induction motor

thumb_up_alt 0 like thumb_down_alt 0 dislike
221 views 2 answers
Description :

How does a single phase induction motor work?

Answer :

As we know that single phase induction is not self started because for self started we require atleast two revolving field but single phase induction motor has only one. So we provide extra ... 1phase IM classified as split phase IM, capacitor start capacitor run, capacitor start induction run.

thumb_up_alt 0 like thumb_down_alt 0 dislike
99 views 1 answer
Description :

Why starter is required for starting an induction motor?

thumb_up_alt 0 like thumb_down_alt 0 dislike
102 views 0 answers
Description :

Why does induction motor have high starting current?

Answer :

In induction motor , the flux produce is quadrature to the applied voltage. Since when we are going to start motor , there is no flux present inside . So in order to lets say compensate it ... times of current to further increase flux. So that is reason for high starting current in induction motor

thumb_up_alt 0 like thumb_down_alt 0 dislike
122 views 2 answers
Description :

Three phase synchronous motor will have how many sliprings?

Answer :

Three phase synchronous motor will have two sliprings.

thumb_up_alt 0 like thumb_down_alt 0 dislike
78 views 1 answer
Description :

Answer :

In a capacitor start motor, the phase displacement between starting and running winding can be nearly 90°.

thumb_up_alt 0 like thumb_down_alt 0 dislike
146 views 1 answer
Description :

Generally, Crawling in squirrel cage induction motors is tendency to run stably at speeds as low as (A) One-third of their synchronous speed (B) One-fifth of their synchronous speed (C) One-seventh of their synchronous speed (D) One-ninth of their synchronous speed

Answer :

Generally, Crawling in squirrel cage induction motors is tendency to run stably at speeds as low as One-seventh of their synchronous speed

thumb_up_alt 0 like thumb_down_alt 0 dislike
83 views 1 answer
Description :

Answer :

If a single phase induction motor runs slower than normal, the most likely defect is worn bearings.

thumb_up_alt 0 like thumb_down_alt 0 dislike
123 views 1 answer
Description :

Split phase induction motor

Answer :

Split phase induction motor : There are two windings used in split phase induction motor. It is a type of single-phase induction motor. There are two winding one is called main winding and ... motor have low starting torque it is used for small fans, blowers, centrifugal pumps, grinders etc.

thumb_up_alt 0 like thumb_down_alt 0 dislike
184 views 1 answer
Description :

explain the working of single phase induction motor.

Answer :

Stator has two winding namely main winding and auxiliary winding.when single phase ac supply is given to the motor,its produces alternating field.this field cut by a cage rotor.so some emf ... due to this emf,rotor flux produced.the interaction between two fluxes produce torque.so rotor rotates.

thumb_up_alt 0 like thumb_down_alt 0 dislike
124 views 1 answer
Description :

Single Phase Induction Motor

Answer :

Single Phase Induction Motor Single phase induction motor is mostly used in home, office, shop and many single phase appliances like pumps,  ... torque and silent operation. It is uses where silent operation is required.

thumb_up_alt 0 like thumb_down_alt 0 dislike
468 views 1 answer
Description :

Why is a capacitor used in a single phase motor and not in three phase motor ?

Answer :

In 1-phase induction motor capacitor work is generate the auxiliary winding current than excite the main winding to rotor starts rotate. After rotor start rotating about 75% of their speed than auxiliary ... emf to start the motor.so,in 3-phase induction motor is self start induction motor.

thumb_up_alt 0 like thumb_down_alt 0 dislike
138 views 6 answers
Description :

Explain Squirrel Cage Induction Generator (SCIG) and also draw a diagram. 

Answer :

Explanation (Operation):- In this system gearbox is used to increase the speed of high speed shaft as per design. IG require reactive power for excitation. Rotor of SCIG is ... , variable voltage output of the generator into the fixed frequency, fixed voltage output required for grid. 

thumb_up_alt 0 like thumb_down_alt 0 dislike
2.7k views 2 answers
Description :

Explain the working of a single phase capacitor start induction motor. 

Answer :

Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc

thumb_up_alt 0 like thumb_down_alt 0 dislike
195 views 2 answers
Description :

What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these

Answer :

What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these

thumb_up_alt 0 like thumb_down_alt 0 dislike
86 views 1 answer
Description :

A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will?

Answer :

A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will not start at all.

thumb_up_alt 0 like thumb_down_alt 0 dislike
124 views 1 answer
Description :

Answer :

Single phase induction motor usually operates on 0.6 power factor lagging.

thumb_up_alt 0 like thumb_down_alt 0 dislike
103 views 1 answer
Description :

Answer :

The starting winding of a single-phase motor is placed in stator.

thumb_up_alt 0 like thumb_down_alt 0 dislike
72 views 1 answer
Description :

The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

Answer :

The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases 

thumb_up_alt 0 like thumb_down_alt 0 dislike
131 views 1 answer
Description :

Torque developed by a three-phase, 400V, induction motor is 100 N -m. If the applied voltage is reduced to 200-V, the d'veloped torque will be

Answer :

Torque developed by a three-phase, 400V, induction motor is 100 N -m. If the applied voltage is reduced to 200-V, the d'veloped torque will be 25 N -m

thumb_up_alt 0 like thumb_down_alt 0 dislike
113 views 1 answer
Description :

A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for

Answer :

A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for 4 poles

thumb_up_alt 0 like thumb_down_alt 0 dislike
158 views 1 answer
Description :

An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is (A) 5.06 kW (B) 0.3 kW (C) 100 kW (D) 83.33 kW

Answer :

An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is 83.33 kW

thumb_up_alt 0 like thumb_down_alt 0 dislike
143 views 1 answer
Description :

Answer :

The starting resistance of a D.C. motor is generally low.

thumb_up_alt 0 like thumb_down_alt 0 dislike
89 views 1 answer
Description :

Answer :

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
66 views 1 answer
Description :

Answer :

For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.

thumb_up_alt 0 like thumb_down_alt 0 dislike
124 views 1 answer
Description :

Answer :

The rotor developed by a single-phase motor at starting is zero.

thumb_up_alt 0 like thumb_down_alt 0 dislike
64 views 1 answer
Description :

In a split-phase induction motor, the resistance/reactance ratios of windings are such that (A) current in the auxiliary winding leads the current in the main winding (B) current in the auxiliary winding lags the current in the main winding (C) both windings develop the same starting torque (D) both windings develop high starting current

Answer :

In a split-phase induction motor, the resistance/reactance ratios of windings are such that current in the auxiliary winding leads the current in the main winding

thumb_up_alt 0 like thumb_down_alt 0 dislike
84 views 1 answer
Description :

In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then (A) the flux is constant (B) the flux first decreases and then increases in the same direction (C) the flux increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor

Answer :

In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then the flux first decreases and then increases in the same direction

thumb_up_alt 0 like thumb_down_alt 0 dislike
79 views 1 answer
Description :

A 3-phase, 4-pole, 50Hz induction motor runs at a speed of 1440 rpm. The rotating field produced by the rotor rotates at a speed of ________ rpm with respect to stator field. (A) 1500 (B) 0 (C) 1440 (D) 60

Answer :

0

thumb_up_alt 0 like thumb_down_alt 0 dislike
946 views 2 answers
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

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

thumb_up_alt 0 like thumb_down_alt 0 dislike
112 views 1 answer
Description :

The torque developed by any 3-phase induction motor at 0.8 p.u. slip is (A) Full-load torque (B) unstable torque (C) starting torque (D) break down

Answer :

The torque developed by any 3-phase induction motor at 0.8 p.u. slip is unstable torque

thumb_up_alt 0 like thumb_down_alt 0 dislike
2.9k views 1 answer
Description :

Answer :

Series motor has got maximum self relieving property.

thumb_up_alt 0 like thumb_down_alt 0 dislike
139 views 1 answer
Description :

Why is a three phase denoted by R, Y, B ?

Answer :

phase 1 ,R =Red colour cable terminal, phase 2 Y=Yellow colour terminal cable,Phase 3 B=Blue colour cable terminal, N =Neutral. For identification.

thumb_up_alt 0 like thumb_down_alt 0 dislike
183 views 2 answers
Description :

When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is (A) 86.6% (B) 50% (C) 57.7% (D) 73.2%

Answer :

When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is 73.2%

thumb_up_alt 0 like thumb_down_alt 0 dislike
77 views 1 answer
Description :

In a three-phase supply floating neutral is undesirable because it way give rise to?

Answer :

In a three-phase supply floating neutral is undesirable because it way give rise to unequal line voltages across the load.

thumb_up_alt 0 like thumb_down_alt 0 dislike
100 views 1 answer
editAsk a Question
...