Quick Answer: Which Motor Is Used For High Starting Torque?

Which starter is used in induction motor?

star delta starterThe star delta starter is used for starting of induction motor above 5 H.P.

Auto Transformer – The necessity of reduction of starting current to avoid failure of motor can be effectively done by auto transformer which consists of a single winding..

What are the methods of speed control of induction motor?

Speed Control Methods of Induction Motor:Control From Stator Side:Control From Rotor Side:Speed Control by frequency variation:Speed Control By Pole Changing:Speed control by varying Supply voltage:Speed control by varying Rotor Resistance:Speed control by injected EMF:Speed control by Cascade Connection:Jan 9, 2017

Which motor is most suitable for best speed control?

There are three speed control motor product groups. The “AC speed control motor unit” that uses the most popular single-phase capacitor-run induction motor, the small and highly efficient “Brushless DC motor unit”, and the “Inverter unit” that combines a three-phase induction motor with a small inverter.

Which motor has high starting current?

Induction MotorStarting Current in Induction Motor: Starting current of induction motor is as high as 5 to 7 times the normal full load current.

Which braking is not possible in series motor?

Regenerative brakingRegenerative braking is not possible in a series motor. Explanation: In regenerative braking, the motor acts as a generator. The back emf is more than the terminal voltage in case of regenerative braking. 2.

How do you reduce motor speed?

So, if you want to decrease speed, decrease voltage. If you want to decrease torque, decrease current. If you increase torque (say by putting a brake on the motor), you are increasing motor torque. But if you don’t change the supply of electrical power, then the mechanical power also won’t change.

Which applications require high starting torque?

Which of the following application requires high starting torque?A. Lathe machine.Centrifugal pump.Locomotive.Air blower.

Which motor Cannot be started on no load?

A series motor should never be started at no load. With no mechanical load on the series motor, the current is low, the counter-EMF produced by the field winding is weak, and so the armature must turn faster to produce sufficient counter-EMF to balance the supply voltage. The motor can be damaged by overspeed.

Why is DC motor current so high?

Answer: The starting current is high as there is no back EMF or counter EMF present in the armature circuit because atstarting counter EMF is zero. … It’s armature has very less resistance due to this it need more current at starting time. Hence DC starters are used to limit the starting current ofmotor.

Why starter is used in DC shunt motor?

Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.

What will happen when DC shunt motor is started with load?

Description : A d.c. shunt motor runs at no load speed of 1140 r.p.m. At full load armature reaction weakens the main flux by 5%. … Answer : If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens this will make armature to take heavy current, possibly burning it.

Why starter is used in induction motor?

The three phase induction motors are self-starting due to rotating magnetic field. But the motors show tendency to draw very high current at the time of starting. … Hence there should be a device which can limit such high starting current. Such a device which limits high starting current is called a starter.

Which one is the most efficient method of braking?

1. DC Injection Braking. DC injection braking is a method of braking in which direct current (DC) is applied to the stationary windings of an AC motor after the AC voltage is removed. This is an efficient and effective method of braking most AC motors.

How do you control motor speed?

Thus, the speed of a DC motor can be controlled in three ways:By varying the supply voltage.By varying the flux, and by varying the current through the field winding.By varying the armature voltage, and by varying the armature resistance.

How do I choose a motor controller?

Choosing a Motor ControllerThe first consideration is the motor’s nominal voltage. … Once you have found a range of controllers that can power the motor with the appropriate voltage, the next consideration is the continuous current the controller will need to supply. … The Control method is another important consideration.More items…•Sep 17, 2018

How much is motor inrush current?

The inrush current (Amps) is high, at 1,500 Amps. This is about 4 times the idle current of the motor, and almost 50% more than the average current while chipping. Inrush current lasts for approximately 2.5 minutes.

What is the relationship between torque and speed in constant type loads?

3. What is the relationship between torque and speed in constant type loads? Explanation: Speed hoist is a perfect example of constant type loads in which torque variation is independent of speed. The speed-torque characteristics of this type of load are given by T=K where K is a constant.

How do you reduce starting current?

Some of the techniques used to reduce the starting current of a squirrel induction motor:Soft starting (voltage control)Variable Frequency Drives (Voltage and frequency control)Star/Delta Starting.Stator impedance and/or resistance starting.Autotransformer Starting.Aug 26, 2015

What will happen if DC motor is used without starter?

What will happen if DC motor is used without starter? Explanation: It would cause intolerably heavy sparking at the brushes which may destroy the commutator and brush-gear. Sudden development of large torque will cause mechanical shock to the shaft, reducing its life.

Which motor is used where high starting torque and wide speed range control is required?

DC series motor1. Which of the following motor is used where high starting torque and wide speed range control is required? Explanation: DC series motor gives the maximum starting torque at starting. With the help of Ward Leonard speed control method various speeds are also available.

Which of the following DC motors is suitable for high starting torque?

Thus, DC series motor is used in conveyors as it provides very high starting torque, which is practically 5 times the rated torque.

Which braking method is the best method for obtaining high braking torque?

PluggingWhich braking method is the best method for obtaining high braking torque? Explanation: Plugging is the best braking method among all braking techniques. In plugging the value of the armature current reverses and the mechanical energy is extracted. A very high braking torque is produced in case of plugging.

Which starting method is best method in induction motor?

The direct on line starter method, of an induction motor is simple and economical. In this method, the starter is connected directly to supply voltage. By this method small motors up to 5 kW rating is started to avoid the supply voltage fluctuation.