Speed Control of DC and AC Machines - Lab Report Example

Speed Control of DC and AC Machines Lab report Insert Insert Introduction The stator and rotor windings make up the DC motor machine. The motor components are excited separately having different sources of voltages of each of the parts. Spend control involves regulating the motor speeds from a point of zero speeds to values of maximum motor rotation speed. Speed rating and variation are achieved by varying the voltages fed to the armature windings. A rectifier is known to be a device that is made use of in supplying power to the motor for rotation at varying levels. Rectifiers have the capability of offering varying voltages in stages required hence speed control implemented. Rectifiers remove the need of having a feedback for the purpose of obtaining speed control via changing the voltages fed to the armature winding of the motor. Speed control of separately excited DC motor by armature voltage variation To be able to achieve separate motor excitation of the DC motor, making use of the steady-state conditions is a necessity. The experimental setup will require subjecting the motor to varying loads and voltages via the rectifier. Single-phase rectifiers that are half-controlled are available. They have a flywheel diode to make power conversion a near perfect process. To achieve experimental results without complex analysis criteria, using a fixed value for the firing angle is recommended. To analyze the speed control of the DC motor, it is imperative to analyze the equation as below; The variables making up the equation are N which represents the speed V stands for terminal voltage R represents external resistance Is known as the flux per pole Armature winding drives the motor and as a result of varying resistance and voltage properties of the armature will enhance the realization of motor speed control. Flux properties of the armature winding make up the magnetic properties that hold the motor operation together. With regard to this, the method for controlling speed of the motor is through the controlling of field and armature properties variations. Figure 1 Dc motor speed control By connecting an additional resistance externally through parallel or series criterion, armature properties are varied hence control of speed. Realization is through connecting it to the motor armature voltage supply circuitry. Using a series rheostat arrangement enables the achievement of speed controls. The external resistance connected in his case affects the armature winding. Method of the field diverter is imperative for achieving variation of the motor magnetic properties. Controlling motor speed via armature control has superior qualities in comparison to the other available means. The strategy offers capabilities of speed control in a fine mode of operation. The features are a uniformity of speed acceleration, sophisticated regulation channels, and enhanced speed control. The downside of the strategy is that they need patterns which are in a standard format. The standardization of arrangement increases the cost as it delivers a lower level of operation efficiency as the motor functions under lighter loading conditions. Operation of a single-phase half controlled bridge rectifier The process made use of in the control of motor speed is the use of a single-phase bridge rectifier criterion. The rectifier with respect to DC motors can be employed as controlled or uncontrolled rectification procedures. Freewheeling diodes are a key feature in this case it occurs both for negative and positive voltage. Half rectification is achieved through clamping of negative voltages. The device cuts off the negative voltage and allows the use of positive voltage parts. Figure 2 Half-controlled rectifier The inputs considered as Vin is a +ve voltage. It proceeds to trigger the SCR S. it is vital to incorporate a diode in the circuitry set up. The flow of current progresses from SCR S1 and goes to the D3 component in the circuit. At E, Read More