Microelectromechanical Devices
... Assume a pure inertia type load and the motor initially operating at point 1. A small step increase in command frequency will initially move the operating point to point 2 (the rated torque) and then steadily increase to point 3. The frequency can then be decreased slightly to achieve the steady sta ...
... Assume a pure inertia type load and the motor initially operating at point 1. A small step increase in command frequency will initially move the operating point to point 2 (the rated torque) and then steadily increase to point 3. The frequency can then be decreased slightly to achieve the steady sta ...
IOSR Journal of Electrical and Electronics Engineering (IOSRJEEE)
... Previously wind turbines were operated at constant speed. The evolution of technology related to wind systems industry leaded to the development of a generation of variable speed wind turbines that present many advantages compared to the fixed speed wind turbines. In this paper the phasor model of D ...
... Previously wind turbines were operated at constant speed. The evolution of technology related to wind systems industry leaded to the development of a generation of variable speed wind turbines that present many advantages compared to the fixed speed wind turbines. In this paper the phasor model of D ...
Tech Notes - Variable capacitors
... applied across the diode. Any diode exhibits this effect (including p/n junctions in transistors), but devices specifically sold as variable capacitance diodes are designed with a large junction area and a doping profile specifically designed to maximise capacitance. Their use is limited to low sign ...
... applied across the diode. Any diode exhibits this effect (including p/n junctions in transistors), but devices specifically sold as variable capacitance diodes are designed with a large junction area and a doping profile specifically designed to maximise capacitance. Their use is limited to low sign ...
International Electrical Engineering Journal (IEEJ) Vol. 5 (2014) No.10, pp. 1567-1575
... freewheeling in an inactive phase are the research hotspot in recent years [9]. Conventional control techniques injecting the similar rectangular phase current command to the stator without the knowledge of non-linearity in the back EMF waveform which causes more amount of ripple in the generated el ...
... freewheeling in an inactive phase are the research hotspot in recent years [9]. Conventional control techniques injecting the similar rectangular phase current command to the stator without the knowledge of non-linearity in the back EMF waveform which causes more amount of ripple in the generated el ...
Starting High Inertia Loads - Rockwell Automation Knowledgebase
... voltage to full voltage at some point in the starting cycle. When the transition is made, there is normally a line current surge. The amount of surge depends on the type of transition being made and the speed of the motor at the transition point. There are two methods for transition from reduced to ...
... voltage to full voltage at some point in the starting cycle. When the transition is made, there is normally a line current surge. The amount of surge depends on the type of transition being made and the speed of the motor at the transition point. There are two methods for transition from reduced to ...
engineering note - Hitachi America, Ltd.
... This is ONLY correct for the SJ300. There are only TWO settings for the L300P: “00” for Normal Operation, and “01” for Energy-Saving Operation. The latter setting seeks to adjust the output voltage at any given output frequency to minimize the motor current, and hence power consumption at that speed ...
... This is ONLY correct for the SJ300. There are only TWO settings for the L300P: “00” for Normal Operation, and “01” for Energy-Saving Operation. The latter setting seeks to adjust the output voltage at any given output frequency to minimize the motor current, and hence power consumption at that speed ...
U4201139143
... followed by a capacitor at dc link. Due to an uncontrolled charging of the capacitor at dc link, draws a pulsed current. With a peak higher than the amplitude of the fundamental input current at ac mains. This results in poor power quality (PQ) at ac mains in terms of poor power factor (PF), high to ...
... followed by a capacitor at dc link. Due to an uncontrolled charging of the capacitor at dc link, draws a pulsed current. With a peak higher than the amplitude of the fundamental input current at ac mains. This results in poor power quality (PQ) at ac mains in terms of poor power factor (PF), high to ...
Synchronous Machines
... When a synchronous generator is excited with field current and is driven at a constant speed, a balanced voltage is generated in the armature winding. If a balanced load is now connected to the armature winding, a balanced armature current at the same frequency as the emf will flow. Since the freque ...
... When a synchronous generator is excited with field current and is driven at a constant speed, a balanced voltage is generated in the armature winding. If a balanced load is now connected to the armature winding, a balanced armature current at the same frequency as the emf will flow. Since the freque ...
Induction motor
An induction or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor therefore does not require mechanical commutation, separate-excitation or self-excitation for all or part of the energy transferred from stator to rotor, as in universal, DC and large synchronous motors. An induction motor's rotor can be either wound type or squirrel-cage type.Three-phase squirrel-cage induction motors are widely used in industrial drives because they are rugged, reliable and economical. Single-phase induction motors are used extensively for smaller loads, such as household appliances like fans. Although traditionally used in fixed-speed service, induction motors are increasingly being used with variable-frequency drives (VFDs) in variable-speed service. VFDs offer especially important energy savings opportunities for existing and prospective induction motors in variable-torque centrifugal fan, pump and compressor load applications. Squirrel cage induction motors are very widely used in both fixed-speed and variable-frequency drive (VFD) applications. Variable voltage and variable frequency drives are also used in variable-speed service.