Gear shifting zero-crossing switching circuit used for fan or cooling fan

Abstract

The invention discloses a gear shifting zero-crossing switching circuit used for a fan or a cooling fan. The gear shifting zero-crossing switching circuit used for the fan or the cooling fan comprises a silicon-controlled switch Q4, a voltage reducing capacitor C1 and a zero-crossing detecting and triggering circuit, wherein the voltage reducing capacitor C1 and the silicon-controlled switch Q4 are connected in parallel; the silicon-controlled switch Q4 is arranged on an L-phase circuit of the fan or the cooling fan in a series connection manner; the control end of the silicon-controlled switch Q4 is connected with the output end of the zero-crossing detecting and triggering circuit; and a protective resistor R4 is further connected to the two ends of the silicon-controlled switch Q4 in parallel. The gear shifting zero-crossing switching circuit used for the fan or the cooling fan has the beneficial effects that the speed decreasing function can be achieved when the silicon-controlled switch Q4 is turned off, explosions of a relay can be prevented, seamless switching can be achieved, reliability is high, safety is good, the impact resistant capacity is high, and the service life is long.

Description

Technical field [0001] The invention relates to a gear adjustment circuit, in particular to a zero-crossing detection and trigger circuit used for fan or cooling fan gear adjustment. Background technique [0002] Existing fan or cooling fan gear shifts generally have a delay circuit, each time shifting is extended by 5-10 seconds, the motor suddenly accelerates or decelerates, the wind suddenly becomes larger or smaller, and there is an obvious over-shifting feeling , Has a great impact on the performance of the motor; the existing gear shifts are implemented by stepping down the motor power control, and the gear shift is realized by reducing the motor power and slowing the rotation speed. Because the voltage of the control module of the circuit control board changes suddenly when shifting High or low will seriously affect the service life of the circuit board and have a greater impact on the normal operation of electronic components. Summary of the invention [0003] The technic...

AI Technical Summary

Problems solved by technology

[0002] Existing fans or cooling fans generally have a delay circuit for shifting gears, each time the shift is extended for 5-10 seconds, the motor suddenly accelerates or decelerates, the wind suddenly becomes larger or smaller, and there is an obvious feeling of excessive shifting , which has a great impact on the performance of the motor; the existing shifting is to implement motor power control through step-down, and realize shifting by reducing the motor power to slow down the rotation speed, because the voltage of the control module of the circuit control board changes suddenly when shifting High or low, which seriously affects the service life of the circuit board and has a great impact on the normal operation of electronic components

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