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the inductance of a solenoid follows as =. A table of inductance for short solenoids of various diameter to length ratios has been calculated by Dellinger, Whittmore, and Ould. [18] This, and the inductance of more complicated shapes, can be derived from Maxwell's equations. For rigid air-core coils, inductance is a function of coil geometry ...
The solenoid can be useful for positioning, stopping mid-stroke, or for low velocity actuation; especially in a closed loop control system. A uni-directional solenoid would actuate against an opposing force or a dual solenoid system would be self cycling. The proportional concept is more fully described in SAE publication 860759 (1986).
Inductor L1 and switch S1 create a standard boost converter, which generates a voltage (V S1) that is higher than V IN, whose magnitude is determined by the duty cycle of the switch S1. Since the average voltage across C1 is V IN , the output voltage ( V O ) is V S1 - V IN .
When this is combined with the definition of inductance =, it follows that the inductance of a solenoid is given by: =. Therefore, for air-core coils, inductance is a function of coil geometry and number of turns, and is independent of current.
When a stator pole is energized, the rotor torque is in the direction that reduces reluctance. Thus, the nearest rotor pole is pulled from the unaligned position into alignment with the stator field (a position of less reluctance). (This is the same effect used by a solenoid, or when picking up ferromagnetic metal with a magnet.) To sustain ...
That is, the back-EMF is also due to inductance and Faraday's law, but occurs even when the motor current is not changing, and arises from the geometric considerations of an armature spinning in a magnetic field. This voltage is in series with and opposes the original applied voltage and is called "back-electromotive force" (by Lenz's law).
(In the case of an electrical circuit, a capacitor to absorb energy stored in (often parasitic) supply side inductance.) High frequency PWM power control systems are easily realisable with semiconductor switches. As explained above, almost no power is dissipated by the switch in either on or off state.
The balance conditions for Anderson's bridge or, equivalently the values of the self-inductance and resistance of the given coil can be found using basic circuit analysis techniques such as KCL, KVL and using phasors. Consider the circuit diagram of Anderson's bridge in the given figure.