Starting Method of Induction Motor: Transient processes involved with the Starting Method of Induction Motor in a variable speed drive require a detailed study. The electric motor and connected load accelerates to the rated speed from rest under the influence of the starting torque. The transient operation during is satisfactory if a sufficiently good starting […]
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Braking of Synchronous Motor: The methods that are employed for Braking of Synchronous Motor are: Regenerative braking while operating on a variable frequency supply Rheostatic braking Plugging Regenerative braking When the motor operates as a variable speed drive motor utilizing a variable frequency supply, it can be regeneratively braked and all the K.E. returned to
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Characteristics of Synchronous Motor: Characteristics of Synchronous Motor are constant speed motors. The speed of the motor is decided by the number of poles and frequency. Compared to an induction motor, it is very sensitive to sudden changes of load. This causes a hunting of the rotor and finally leads to stability problems. It has
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Torque Speed Characteristics of Induction Motor: From Eq. 1.27 it can be observed that the maximum torque is independent of rotor resistance. However, the slip at which the maximum torque occurs changes with rotor resistance. When the rotor resistance is increased, so is the slip for maximum torque, and the stable operating slip range of
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Speed Torque Characteristics of Series Motor: The field winding is connected in series with the armature (Fig. 1.2(b)). The armature current and field current are the same. The operating Speed Torque Characteristics of Series Motor may be deduced for a series motor in the same way as described before for shunt motor/separately excited motor using
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PLC Hardware Components: PLC Hardware Components – The input and output interface modules consists of an I/0 rack and individual I/O modules. Input interface modules, accept signals from the machine or process devices (120V ac) and convert them into signals (5V dc) that can be used by the controllers. Output interface modules convert controller signals
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Digital Process Control: A digital process control functionally needs to operate in much the same way as a conventional analog controller. That is, it must provide facilities to raise or lower the set point and to provide proportional, 2-term or 3-term control. It must be capable of operating in one of many modes including, manual,
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Primary Standard: Primary Standard – One arrangement is a carefully designed quartz crystal oscillator operating in the range 50 to 100 kHz, having a low temperature coefficient, constant amplitude output and voltage regulated power supply. The crystal oscillator has a long time (several months) frequency stability of a few parts in a 100 million, without
Sensors Based Computer Data Systems: This Sensors Based Computer Data Systems describes hardware/software which is commercially available at several levels of completeness, ranging from single board computer “front ends” to stand alone system and high level programming languages. Even the simplest and least expensive devices require considerable electronics/computer expertise on the part of the user,
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Data Logger Operation: Data Logger Operation – For proper understanding of a Data Logger Operation, it is essential to understand the difference between analog and digital signals. For example, measurement of temperature by a milli voltmeter, whose needle shows a reading directly proportional to the emf generated by the thermocouple, is an analog signal. However,
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