Economizer of alternative-current contactor

Abstract

The invention discloses an economizer of an alternative-current contactor, and the economizer comprises a peripheral circuit which is connected with the alternative-current contactor and a signal processor which is connected with the peripheral circuit; the signal processor comprises a comparison circuit, a zero-crossing detection circuit, a pulse width modulation circuit, a selection circuit, a low-voltage detection circuit and a signal synthesis circuit. Due to the adoption of the economizer, narrow pulse of small current passing through the alternative-current contactor can be changed along with the variation of external voltage, the width of the narrow pulse is reduced while the external voltage is increased, the current passing by the economizer is reduced, and thus the burning of the coil caused by the overlarge current can be avoided. When the external voltage is dropped, the width of the narrow pulse outputted by the economizer is increased, the current passing by the alternative-current contactor is correspondently increased, and thus the disconnection of the alternative-current contactor because of reduced current can be prevented; and moreover, the power consumption of the alternative-current contactor can be further reduced, and the burning of a contactor coil because of over-current can be avoided.

Description

technical field [0001] The invention belongs to the technical field of energy-saving of low-voltage electric appliances, and in particular relates to an energy-saving device of an AC contactor. Background technique [0002] A contactor refers to an electrical appliance in the industry that uses a coil to flow current to generate a magnetic field to close the contacts to control the load. The contactor consists of an electromagnetic system (iron core, static iron core, electromagnetic coil) contact system (normally open contact and normally closed contact) and an arc extinguishing device. The principle is that when the electromagnetic coil of the contactor is energized, it will generate a strong magnetic field, so that the static iron core will generate electromagnetic attraction to attract the armature, and drive the contact to move, and the contactor will pull in. When the coil is de-energized, the electromagnetic attraction disappears, the armature is released under the a...

AI Technical Summary

Problems solved by technology

[0004] At present, the existing AC contactor energy saver also adopts the method of high current pull-in and low current maintenance, but the existing technology has the following defects: At present, when saving energy, the small current is usually kept unchanged, or it is used to control this small current The DC pulse width remains constant

The limit value of contactor release and complete disconnection is 20%-75% of its rated control power supply voltage Us, and the circuit built with discrete components cannot meet this standard

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