Demonstration aids for DC motor with adjustable internal resistance

Abstract

The invention relates to a direct current motor demonstration teaching aid with an internal resistor adjustable. The direct current motor demonstration teaching aid with the internal resistor adjustable comprises a base, a coil A, a coil B and the simulated motor internal resistor. The coil A and the coil B are wound on a rotating shaft of a motor, the coil A and the coil B are essentially in the same set, two wires are led out after the coil is cut off from the center, and the two wires are connected to a pair of copper semi-rings A. The resistance on the simulated motor internal resistor is adjustable, and the simulated motor internal resistor can be connected to a pair of simulated motor internal resistor binding posts in an inserting mode. A direct current voltmeter is used for detecting the working voltage, the internal voltage and the mechanical voltage of a power supply. The direct current motor demonstration teaching aid with the internal resistor adjustable has the advantages that influences on the rotating speed and the working currents of the motor by the changes of the internal resistance, the changes of magnetic field intensity, and the changes of the magnetic field direction of the direct current motor can be demonstrated, and the influences on abrasion of the rotating shaft of the motor on a rotating shaft support when magnetic poles are asymmetric relative to the coils can also be demonstrated; the voltages of the power supply can be detected and can be compared with the mechanical voltage and the internal voltage, energy conservation during working of the motor can be verified, and therefore the direct current motor demonstration teaching aid with the internal resistor adjustable is a demonstration teaching aid with high operability for direct current motor teaching and research.

Description

technical field [0001] The invention relates to the field of research on the working principle of a DC motor for teaching equipment, in particular to a demonstration teaching aid for a DC motor with adjustable internal resistance. Background technique [0002] At present, the functions of DC motor models for teaching are single, and most of them are composed of fixed stators, rotors, brushes, slip rings, etc. After the constant voltage source is connected, they will rotate at a constant speed to demonstrate the working principle of DC motors; however, if you want to It is more difficult to study the influence of DC motor internal resistance change, magnetic field strength, and magnetic field direction on motor speed and operating current, because all parts of the DC motor model sold by the manufacturer are fixed and immovable; it is also impossible to measure the power supply voltage and internal Quantitative relationship between voltage and mechanical voltage, so a DC motor...

AI Technical Summary

Problems solved by technology

[0002] At present, the functions of DC motor models for teaching are single, and most of them are composed of fixed stators, rotors, brushes, slip rings, etc. After the constant voltage source is connected, they will rotate at a constant speed to demonstrate the working principle of DC motors; however, if you want to It is more difficult to study the influence of DC motor internal resistance change, magnetic field strength, and magnetic field direction on motor speed and operating current, because all parts of the DC motor model sold by the manufacturer are fixed and immovable; it is also impossible to measure the power supply voltage and internal The quantitative relationship between voltage and mechanical voltage, so a DC motor for teaching and research is needed to solve the defects of insufficient demonstration functions in middle school physics motor demonstration teaching aids

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