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Answer :

A direct online starter is used for starting motors up to 5 H.P.

Related questions

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

Last Answer : Three point starter can be used for both shunt and compound motor.

Last Answer : A three point starter is considered suitable for shunt as well as compound motors.

Description : Damper winding is provided in 3 phase synchronous motors to :

Last Answer : Damper winding is provided in 3 phase synchronous motors to : provide starting torque and prevent hunting

Description : Stepper motors are used in  (1) printers (2) lifts (3) amplifiers (4) oscillators

Last Answer : Stepper motors are used in printers 

Description : Slot harmonics are reduced in induction motors by using (A) fractional-pitch windings (B) fractional-slot windings (C) integral-slot windings (D) distributed windings

Last Answer : Slot harmonics are reduced in induction motors by using fractional-slot windings

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

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

Description : Which of the following test is usually conducted to determine the efficiency of traction motors ? (A) Field’s test (B) Swinburne’s test (C) Hopkinson’s test (D) Retardation test.

Last Answer : Which of the following test is usually conducted to determine the efficiency of traction motors ? (A) Field’s test (B) Swinburne’s test (C) Hopkinson’s test (D) Retardation test.

Description : Which of the following motors is being extensively used in servo applications ? A. AC motor B. Field controlled dc motor C. Armature controlled dc motor D. None of these

Last Answer : Which of the following motors is being extensively used in servo applications ? A. AC motor B. Field controlled dc motor C. Armature controlled dc motor D. None of these

Description : In case of conductively compensated D.C. series motors, the compensating winding is provided?

Last Answer : In case of conductively compensated D.C. series motors, the compensating winding is provided in series with armature winding.

Last Answer : In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.

Last Answer : When two D.C. series motors are connected in parallel, the resultant speed is normal speed.

Last Answer : In D.C. shunt motors as load is reduced the speed will remain almost constant.

Last Answer : Starters are used with D.C. motors because to restrict armature current as there is no back e.m.f. while starting.

Last Answer : Differentially compound D.C. motors can find applications requiring low starting torque.

Last Answer : The capacitors used in single-phase capacitor motors have no polarity marking.

Last Answer : Most of the fractional horsepower motors have either plain or sleeve bearings.

Last Answer : As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for sound equipment.

Description : What is the difference between synchronous and asynchronous motors?

Last Answer : The motor which rotates at constant speed is called synchronous motor. And that constant speed is called as synchronous speed.  And the motor which does not rotates at constant speed are called asynchronous motor. Asynchronous motor is also called as Induction motor.

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 ... the outer high resistance winding. (D) Large current flows through the inner low resistance winding.

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

Last Answer : Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of D.C. series motor.

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

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

Last Answer : The ratio of starting torque to full-load torque is least in case of shunt motors.

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

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

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

Description : How is a three phase cage induction motor self starting?

Last 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 ... torqe also pulsating. In induction motor this angle theta is not pulsating.so it is self starting 

Description : Is induction motor is self starting?

Last Answer : Single phase induction motor is not self starting. Three phase induction motor is self starting.

Last Answer : Capacitor start motor has high torque in starting

Description : How to Replace a Starter

Last Answer : How to Replace a Starter The starter is where it all begins. Your car is just sitting there and ready to go, but it won't. A charge is supposed to be sent to the starter and then ... the battery and tighten the connection. Start the engine to make sure that all connections have been made properly.

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

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

Description : Draw the wiring diagram of fluorescent tube. Explain the working of choke and starter. 

Last Answer : Fluorescent lamp:- Operation:- When switch is ON current flows through the choke-filament no1- starter-filament no. 2- to neutral, At that time choke induces high voltage which is applied to ... at the time of starting. ii) Starter: To make and break the circuit to start the tube. 

Description : State any four advantages of soft starter.

Last Answer : Advantages of soft starter: 1. Very low line voltage drops on motor operation 2. Reduced energy losses in the lines 3. System efficiency increases 4. Very smooth starting & operation 5. As ... may lead to lower MD billing. 13. Less mechanical maintenance. 14. Saving in operating costs.

Description : State function of starter and ELCB. (Earth Leakage Circuit Breaker)

Last Answer : i) Function of Starter:- 1. To prevent the high starting current OR to minimize the starting current. 2. To give supply failure protection 3. To give over load and short circuit protection ... an installation and cut off the circuit from power supply and avoid electrical shock to the person.

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

Description : what is the difference between four point starter and three point starter?

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

Last Answer : Synchronous motors are generally not self-starting because the direction of instantaneous torque reverses after half cycle.

Description : Differentiate between direct and indirect extrusion. Discuss their relative merits and demerits. 

Last Answer : Direct extrusion Indirect extrusion Simple, but the material must slide along the chamber wall. In this case, material does not move but die moves. High friction forces must ... be used for extruding long extrudes. Support of the ram becomes a problem as work length increases.

Description : Identify direct addressing instructions from following instructions : (i) MOV RO, R5 (ii) MOV RO, 80 H (iii) MOV RO, #75H (iv) ADD A, 45 H

Last Answer : Instructions ii) and iv) are direct addressing as 80H and 45H are direct addresses

Description : Direct Extrusion process

Last Answer : Direct Extrusion process Direct extrusion process is shown in fig. The raw material used is a billet. It consists of a press operated ram and a cylinder or container into which the heated ... for extruding long extrudes. 2) Support of the ram becomes a problem as work length increases.

Description : Direct Current (DC) Next Topic : Alternating current (AC)

Last Answer : Direct Current (DC) is the unidirectional electric current. Uni meaning is one. And the flow of charge in same direction. We know that conventional current flow from positive terminal of battery to ... The magnitude of DC may constant or vary but direction do not change with respect to time.

Description : advantages and disadvantages of direct coupled amplifier over RC coupled amplifier. 

Last Answer : Advantages:  Due to absence of coupling capacitors, the gain does not reduce on the lower frequency side.  This amplifier can amplify dc signals. Reduced cost and complexity due to absence of ...   The output waveform has a dc shift.  Poor frequency response at a higher frequency.

Description : Describe the difference between direct and alternating current.

Last Answer : Direct current is the flow of electricity or charge in one direction..  Alternative current is the flow of charge that doesn't flow in one direction. 

Description : Explain with schematic diagram direct distribution of solar energy.

Last Answer : Explain with schematic diagram direct distribution of solar energy: Solar energy reaching earth's surface consists of two components: i) Direct solar energy, ii) Diffused solar energy. Direct solar energy ... radiation. It is very intense radiation and it can produce sun burns and shadows.

Description : With neat diagram explain calibration of energy meter by direct loading method.

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Description : State the need of cascade amplifier and draw circuit diagram of 2-stage direct coupled amplifier.

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Description : Compare RC coupled, transformer coupled and direct coupled amplifier based on four points.

Last Answer : Parameter RC coupled Transformer coupled Direct coupled  Coupling element Resistor and capacitor Transformer No element Impedance matching Poor Excellent good Frequency ... Low frequency amplifier,opamp Size and cost small Large and bulky least

Description : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is

Last Answer : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is √3/2

Description : In the case of direct current?

Last Answer : In the case of direct current magnitude and direction of current remains constant.