Category: Dynamics of Electrical Drives

Load Equalisation in Electrical Drives

Load Equalisation in Electrical Drives: Load Equalisation in Electrical Drives – In some drive applications, load torque fluctuates widely within short intervals of time. For example, in pressing machines a large torque of short duration is required during pressing operation, otherwise the torque is nearly zero. Other examples are electric hammer, steel rolling mills and […]

Steady State Stability of Drive

Steady State Stability of Drive: Equilibrium speed of a motor-load system is obtained when motor torque equals the load torque. Drive will operate in steady-state at this speed, provided it is the speed of stable equilibrium. Concept of Steady State Stability of Drive has been developed to readily evaluate the stability of an equilibrium point […]

Time and Energy Loss in Transient Operations

Time and Energy Loss in Transient Operations: Starting, braking, speed change and speed reversal are transient operations. Time and Energy Loss in Transient Operations can be evaluated by solving Eq. (2.19) along with motor circuit equations. When T and TL are constants or proportionals to speed, Eq. (2.19) will be a first order linear differential […]

Classification of Load Torques

Classification of Load Torques: As we know already, the nature of Classification of Load Torques depends on particular application. A low speed hoist is an example of a load where the torque is constant and independent of the speed (Fig. 2.3). At low speeds, windage torque is negligible. Therefore, net torque is mainly due to […]

Components of Load Torques

Components of Load Torques: Components of Load Torques Tl can be further divided into following components: (i) Friction torque TF : Friction will be present at the motor shaft and also in various parts of the load. TF is equivalent value of various friction torques referred to the motor shaft. (ii) Windage torque, Tw : When a motor […]

Motor Design Parameters

Motor Design Parameters: Different parts of a load may be coupled through different mechanisms, such as gears, V-belts and crankshaft. These parts may have different speeds and different types of Motions such as rotational and translational. This section presents methods of Motor Design Parameters finding the equivalent moment of inertia (J) of motor-load system and equivalent […]

Four Quadrant Operation of Motor Drive

Four Quadrant Operation of Motor Drive: For consideration of Four Quadrant Operation of Motor Drive, it is useful to establish suitable conventions about the signs of torque and speed. Motor speed is considered positive when rotating in the forward direction. For drives which operate only in one direction, forward speed will be their normal speed. […]

Torque Equation of Motor Load System

Torque Equation of Motor Load System: A motor generally drives a load (machine) through some transmission system. While motor always rotates, the load may rotate or may undergo a translational motion. Load speed may be different from that of motor, and if the load has many parts, their speeds may be different and while some […]