Influence of Rotor Parameters on Torque Speed Curves We know that the rotor resistance and reactance influence the shape of the torque–speed curve. The designer can vary both of these parameters, and we will explore the pros and cons of the various alternatives. To limit the mathematics the discussion will be mainly qualitative, but it […]
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Stable Operating Regions of Induction Motor In addition to having sufficient torque to start the load it is obviously necessary for the motor to bring the load up to full speed. To predict how the speed will rise after switching on we need the torque–speed curves of the motor and the load, and the total
Starting Methods of Induction Motors Our everyday domestic experience is likely to lead us to believe that there is nothing more to starting a motor than closing a switch, and indeed for most low-power machines (say up to a few kW ) – of whatever type – that is indeed the case. By simply connecting
Process of Motor Selection The process of motor selection often highlights difficulties in three areas. Firstly, there is a good deal of overlap between the major types of motor and drive. This makes it impossible to lay down a set of hard and fast rules to guide the user straight to the best solution for
Analog to Digital Conversion Physical quantities like temperature, pressure, velocity etc. can be measured using transducer circuits. The resulting analog voltage produced by a transducer is often converted to digital form so that it can be processed by a computer or a digital signal processor (DSP). The conversion of an analog signal to digital utilizes
Method of Measuring Displacement, Velocity and Acceleration Displacement is a quantity that indicates the change in position of a body or point. Angular displacement refers to a rotation that can be measured in degrees or radians. Displacement transducers can be either contacting or noncontacting. Contacting transducers typically use a sensing shaft with a coupling device
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Method of Measuring Strain, Pressure, and Flow Rate Strain is the deformation, either expansion or compression, of a material due to a force acting on it. For example, a metal rod or bar will lengthen slightly when an appropriate force is applied, as illustrated in Figure 1(a). Also, if a metal plate is bent, there
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Methods of Measuring Temperature Temperature is the most common physical parameter that is measured and converted to electrical form. Several types of temperature transducers respond to temperature and produce a corresponding indication by a change or alteration in a physical characteristic that can be detected by an electronic circuit. Common types of temperature transducers are
Applications of Wheatstone Bridge The Wheatstone bridge circuit can be used to precisely measure resistance. However, the bridge is most commonly used in conjunction with transducers to measure physical quantities such as strain, temperature, and pressure. Transducers are devices that sense a change in a physical parameter and convert that change into an electrical quantity
Operation of PMMC Instrument Most analogue (pointer-on-scale) instruments rely on three factors for their operation: a deflecting torque; a restoring torque; and a damping torque. Deflecting Torque: Essentially, a moving coil meter is a current measuring device. The current to be measured is passed through a multi-turn coil suspended between the poles of a permanent