Found 1006 Articles for Electronics & Electrical

The torque-pulse rate characteristics of a stepper motor is the graph plotted between the electromagnetic torque and the stepping rate. It gives the variation of electromagnetic torque as a function of stepping rate in pulses per second (pps). A stepper motor is usually described by two characteristic curves as shown in the figure.Curve-1 represents the pull-in torque characteristic of the stepper motor and it gives the maximum value of stepping rate at which the motor can start, synchronise, stop or reverse for different values of load torque.Curve-2 represents the pull-out torque characteristic and it shows the maximum stepping rate at ... Read More

Basics of ServomotorsServomotors are the electromechanical energy conversion devices. In other words, a Servomotors is a rotary actuator or linear actuator which is used for precise control of linear or angular position, velocity and acceleration.A servomotor consists of an electric motor coupled with a sensor for position feedback. Servomotors are used in feedback control systems as the output actuators. Hence, servomotors are also called as control motors.Servomotors are not used for continuous energy conversion. The power ratings of servomotors vary from a fraction of a watt to a few hundred watts. The servomotors have low rotor inertia and hence they ... Read More

Basics of Stepper MotorThe stepper motor or stepping motor is an electromechanical energy conversion device which has a rotor movement in discrete steps. The number of pulses fed into the control circuit of the motor determines the angular rotation of the rotor.Each input pulse initiates the drive circuit of the motor which produces one step of angular movement. The drive circuit has inbuilt logic which causes appropriate windings to be energised and de-energised by the solid state switches in the required sequential manner. In a stepper motor, the angular movement of the rotor is in steps, so this motor may ... Read More

A stepper motor is an electromechanical energy conversion device which converts electrical input power into mechanical output power. Basically, it is a brushless motor that can divide a full rotation into an equal number of steps and the operation of the motor can be accurately controlled with no-feedback system when the motor is properly sized to the application.Practically, the stepper motors are manufactured in sizes ranging from milli-watts to hundreds of watts and the maximum torque values upto 15 N-m and the step angle from 1.8° to 90° mechanical.Types of Stepper MotorsDepending upon the rotor arrangement, the stepper motors are ... Read More

A split-phase induction motor is a type of single-phase induction motor in which the stator is provided with a starting or auxiliary winding (S) and a main or running winding (M). The starting winding is displaced by 90° from the main winding as shown in the figure.The starting winding operates only during the brief period when the motor starts up. The starting and the main windings are so designed that the starting winding (S) has a high resistance and relatively low reactance while the main winding (M) has relatively low resistance and high reactance so that the currents flowing in ... Read More

A shaded pole induction motor is a type of self-starting 1-phase induction motor. It consists of a stator and a squirrel cage type rotor. The stator of the shaded pole motor is made up of salient poles and each pole is slotted on a side and a copper ring is fitted on the smaller part of the slot as shown in the figure. The part with copper ring is known as shaded pole and the copper ring is known as shading coil which is usually a single turn coil.The main winding surrounds the entire pole and is given the 1-phase ... Read More

A 1-phase supply produces a pulsating magnetic field which does not rotate in the space. Therefore, a 1-phase supply cannot produce rotation in a stationary rotor. Although, like a 3-phase supply, the 2-phase supply can also produce a rotating magnetic field of constant magnitude. Therefore, all the single-phase induction motors, except shaded pole induction motor, are started as 2-phase motor. Once so started, the motor will continue to run on the 1-phase supply.How does a 2-Phase Supply Produce Rotating Magnetic Field of Constant Magnitude?Consider a 2-phase, 2 pole motor, where the phases A and B are fed by a balanced ... Read More

A repulsion-start induction-run motor consists of a stator carrying a single-phase exciting winding and a rotor which has a closed type armature winding with a commutator and brushes. The brushes on the commutator are short circuited. In the repulsion-start induction-run motor, the action of repulsion motor is combined with that of a 1-phase induction motor.This motor is started as a repulsion motor with a corresponding high-starting torque. At some predetermined speed, a centrifugal switch short-circuits the commutator segments so that the motor operates as a 1-phase induction motor.The centrifugal device is fitted on the rotor shaft of the motor. When ... Read More

In the repulsion induction motor, a high starting torque is due to repulsion motor action. When it is running, the repulsion-induction motor functions through a combination of repulsion motor and induction motor action.Construction of Repulsion Induction MotorThe construction of a 2-pole repulsion induction motor is shown in the figure.It consists of a stator which carries a single distributed winding fed from a 1phase supply. The rotor of the repulsion-induction motor has two independent windings placed one over the other.The inner winding is a squirrel cage winding with rotor bars permanently short-circuited.The outer winding is a repulsion commutator armature winding which ... Read More

The printed circuit board (PCB) motor consists of a rotor in the form a disc which is made up of non-magnetic and non-conducting material. Hence, the printed circuit board motor is also called as disc armature motor. The basic construction of a printed circuit board motor is shown in the figure.The whole armature winding of the motor and the commutator are printed in copper on both sides of the rotor disc. The brushes are placed around the inner periphery of the rotor disc.The disc armature of the motor is placed between two sets of permanent magnet poles which are mounted ... Read More