CN2057040U

CN2057040U - Over-voltage protector for household electric appliances

Info

Publication number: CN2057040U
Application number: CN 89205223
Authority: CN
Inventors: 龙斌
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-07-10
Filing date: 1989-07-10
Publication date: 1990-05-09

Abstract

The utility model relates to an over-voltage protector for household electric appliances, which comprises a transformer, a bridge-typed rectifier, an overvoltage relay, a rectifier diode and a thyristor. When the power supply voltage is normal, the relay does not operate, and the thyristor is controlled to make the power supply conducted normally; however, when the power supply voltage is over the normal value, the relay operates, the thyristor is controlled to make the power supply switch off reliably to protect the electric appliances from being damaged. The utility model has the advantages of simple structure and reasonable design; the switching on and switching off can realize automatic control.

Description

Over-voltage protector for household electric appliances

This utility model belongs to the servicing unit of household electrical appliance, specifically a kind of overvoltage protector of household electrical appliance.

Present over-pressure safety device of the prior art has two kinds: a kind ofly be and the earth leakage protector fit applications, control circuit mainly is made up of integrated package inverter, bridge rectifier, triode, voltage-stabiliser tube, relay etc., but complex circuit, price are very expensive; Another kind has under-voltage, two kinds of function and protectings of overvoltage, control circuit mainly is made up of transformer, bridge rectifier, voltage-stabiliser tube, CMOS integrated package, triode, bidirectional triode thyristor, has above-mentioned complex circuit, weak point that price is expensive equally.

Task of the present utility model is that one of proposition is comparatively simple, and cost is lower, volume is less compared with prior art, especially is fit to the overvoltage protector of the household electrical appliance in rural area.

Household electrical appliance overvoltage protector of the present utility model is characterized in that having formed the The Trigger of Bidirectional Triode Thyristor control circuit by two contacts of overvoltage relay, the secondary of two diodes, electric capacity and transformers.

Accompanying drawing is a line map of the present utility model.

Be explained in detail below in conjunction with the solution of accompanying drawing to utility model

Fastp-acting fuse RLS, controllable silicon KS and household electrical appliance Rfz are composed in series the reverse-blocking tetrode thyristor major loop; The input of bridge rectifier D and transformer secondary winding B₂Two ends link to each other, its output and variable resistor W, overvoltage relay DJ are connected into the voltage detecting loop; Two detector diode D₁、D ₂, normally closed, the normally opened contact DJ of overvoltage relay DJ₁、DJ ₂With transformer secondary winding B₃Series connection, capacitor C₂Be connected to diode D₂Negative pole and transformer secondary B₃Mid point O; Two contacts of overvoltage relay junction b extremely links to each other transformer secondary winding B with silicon controlled control₃Mid point O be connected with the anode of controllable silicon KS; Resistance R, capacitor C₁Be connected to silicon controlled anode, negative electrode two ends after the series connection.

Circuit of the present utility model is work like this: by variable resistor W, the operating point of overvoltage relay DJ is adjusted to the normal critical value of civil power.When line voltage just often, the normally-closed contact DJ of overvoltage relay DJ ₁Be failure to actuate, apply a forward voltage at the control utmost point two ends of controllable silicon KS, controllable silicon conducting, household electrical appliance operate as normal; When line voltage raises suddenly, overvoltage relay action, its normally-closed contact DJ ₁Open normally opened contact DJ ₂Closure applies a reverse voltage between controllable silicon KS control utmost point negative electrode, work ends, and load is cut off the electricity supply, and shields.When voltage recovers just often, repeat said process, the controllable silicon conducting, household electrical appliance are work as usual.

One of embodiment of this protector is: resistance R, W are 100 Ω, C ₁, C ₂Be 0.2 μ f and 20 μ f, controllable silicon is selected KS for use _25-b-21, in this case, transformer secondary B ₃Mid point be ± 1 volt to the voltage of the SCR control utmost point.

This overvoltage protector protection domain is 260-400V, and the power maximum of its load can reach 4KW. Have simple in structure, with low cost, safe and reliable, the characteristics that volume is little, use abnormal vast rural area that is particularly suitable for powering.

Claims

1, a kind of household electrical appliance overvoltage protector, it comprises a controllable silicon major loop, pays limit B by transformer for one ₂, bridge rectifier D, the rectification testing circuit that overvoltage protector DJ winding and variable resistor W form, a controlled trigger control circuit is characterized in that described controllable silicon trigger control circuit is the contact DJ by overvoltage relay DJ ₁, DJ ₂, diode D ₁, D ₂, capacitor C ₂, transformer is paid limit B ₃Deng composition, the anode of controllable silicon KS had both passed through the neutral point O and the diode D of transformer ₁Negative pole, D ₂Anodal linking to each other is again with capacitor C ₂Negative pole links to each other, and the control utmost point of controllable silicon KS passes through the contact DJ of relay DJ respectively ₁, DJ ₂With diode D ₁Positive pole, D ₂Negative pole and capacitor C are anodal to link to each other.