No-load energy-saving device for single-phase motor

Abstract

An unloaded energy-saving device of a single-phase motor comprises a main circuit, a control circuit and a power supply circuit for supplying a working power to the control circuit. The main circuit comprises a bridge rectifier QL, a single-phase motor connected in series with an input terminal of the bridge rectifier QL, a first inductor L1 and a triode T1 connected in series, and a second inductor L2 and a triode T2 connected in series with an output terminal of the bridge rectifier QL. The control circuit comprises a square wave oscillator, a power factor regulator, a transistor T1 and a transistor T2 which are alternately turned on under the control of the square wave oscillator; When the motor is light load, the power factor decreases, the power factor regulator automatically makes the oscillation frequency of the square wave oscillator increase, the voltage of the motor decreases, the reactive current decreases, and the power factor increases, which has a high energy saving effect. During voltage regulation, the first inductor L1 and the second inductor L2 alternately have current passing through them, the current of single-phase motor is continuous, and the harmonic component is small, which can greatly reduce the pollution to the power network.

Description

technical field [0001] The invention relates to an energy-saving device for a single-phase motor. Background technique [0002] When the single-phase motor is no-load or light-loaded, its power factor drops, and the method of reducing voltage can be used to compensate the power factor. The existing energy-saving devices for single-phase motors generally use silicon controlled rectifiers. The pass angle realizes voltage regulation to achieve energy saving, but the high-order harmonic components of the motor current are relatively large when using thyristors, which will cause pollution to the power grid. Contents of the invention [0003] Aiming at the deficiencies of the prior art, the present invention proposes a no-load energy-saving device for single-phase motors, which has good energy-saving effect, and the high-order harmonic component of the current is small during voltage regulation, which can reduce the pollution to the power grid. [0004] The technical solution o...

AI Technical Summary

Problems solved by technology

[0002] When the single-phase motor is no-load or light-loaded, its power factor drops, and the method of step-down can be used to compensate the power factor. The existing energy-saving devices for single-phase motors generally use silicon controlled rectifiers. The pass angle realizes voltage regulation to achieve energy saving, but the high-order harmonic components of the motor current are relatively large when using silicon controlled rectifiers, which will cause pollution to the power grid

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