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Protection Circuit

Index 11

Motor protector 10

Published:2011/4/27 20:49:00 Author:Ecco | Keyword: Motor protector

Motor protector 10
The motor protector described in the example can cut off the power supply when any phase of power in three-phase AC motor being lacking, it can prevent winding overheating damage due to broken phase operation. The working principle The motor protector circuit is composed of the voltage detection circuit and protection controlling execution circuit, it is shown as Figure 8-46. Starting control circuit is composed of stopping button Sl, starting button S2 and AC contactor KM (the original motor starting circuit). Voltage detection circuit is composed of the diodes VDl-VD3, Zener diode VSl-VS3, resistors Rl-R6, capacitors Cl-C3 and optocouplers VLCl-VLC3. Protection control circuit consists of transistors V, relay K, the diode VD4 and resistor R7. Rl, R3 and R5 use 1-2W metal film resistors; R8, R4, R6 and R7 use 1/4W carbon film resistors or metal film resistors. Cl-C3 select aluminum electrolytic capacitors with voltage in 16V. VDl-VD4 use 1N4007 silicon rectifier diodes. VSl-VS3 select lW, 9 · IV silicon voltage regulator diodes. V uses S8050, 3DG805O, BC136 or other models NPN silicon transistors. VLCl-VLC3 use 4N25 or MCT2E, TL206 coupler. K uses 9V DC relay. (View)

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The fridge over voltage, under voltage, power delay protector composed of 556

Published:2011/4/19 3:08:00 Author:Ecco | Keyword: fridge, over voltage, under voltage, power delay , protector

The fridge over voltage, under voltage, power delay protector composed of 556
The chart shows a fridge over voltage, under voltage, power delay protector circuit. The circuit consists of over and under voltage sampling circuit, trigger circuit, delay circuit, the buck rectifier circuit. And the buck rectifier circuit provides DC voltage for the entire circuit. (View)

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The internal structure of HL601A

Published:2011/4/14 6:29:00 Author:may | Keyword: internal structure

The internal structure of HL601A
HL601A is thick film integrated circuit.It can achieve dual-level protection of signal's over current, over voltage, over heating, etc. Its features include precise threshold, fast speed, and high reliability. (View)

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Three phases of phase lack protection circuit

Published:2011/3/27 22:45:00 Author:Jessie | Keyword: Three phases, phase lack protection

Three phases of phase lack protection circuit
This is a kind of protection circuit used for three-phase three-wirepower phase lack, A, B and C lack any phase, light-coupler output level is lower than comparator's reversed-phase input terminal's benchmark voltage, comparator output low level, blockade PWM drive signal, andcut offpower. Comparator input polarity fluctuant, also can use a high level blockade PWM signal. This phase lack protection circuit uses high light-coupler isolation, safe and reliable, RP2, RP1 used to adjust phase lack protection movement threshold. (View)

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Bridge type picked up horn protection circuit (2)

Published:2011/3/23 3:56:00 Author:Jessie | Keyword: horn protection

Bridge type picked up horn protection circuit (2)
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The principle diagram of IGBT over current protection circuit

Published:2011/4/10 21:50:00 Author:may | Keyword: IGBT, over current protection

The principle diagram of IGBT over current protection circuit
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The application circuit of EXB841

Published:2011/4/10 21:28:00 Author:may | Keyword: application

The application circuit of EXB841
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The principle circuit of EXB841

Published:2011/4/10 21:30:00 Author:may

The principle circuit of EXB841
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The application circuit of EXB850

Published:2011/4/10 21:31:00 Author:may

The application circuit of EXB850
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The battery voltage protection indicating circuit diagram

Published:2011/4/7 22:14:00 Author:Ecco | Keyword: battery voltage, protection indicating

The battery voltage protection indicating circuit diagram
Power, low battery indication In the following circuit when the battery is OK, it indicates the green LED, the LED is the power indicator during operation. When the battery voltage is lower than the default, the red LED light will light up. (View)

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A power-saving three-phase asynchronous motor-phase protection device

Published:2011/4/6 1:04:00 Author:Ecco | Keyword: power-saving , three-phase asynchronous , motor-phase , protection device

A power-saving three-phase asynchronous motor-phase protection device
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The application of IGBT in CO2 gas shielded welding power supply

Published:2011/4/8 1:38:00 Author:may | Keyword: IGBT, CO2 gas, shielded welding, power supply

The application of IGBT in CO2 gas shielded welding power supply

1, In order to accurate control the process of short circuit, main circuit adopts IGBT with very high working frequency as switch power device. The main circuit of CO2 gas shielded welding power supply adopts full bridge structure. 2, 80C196KB control system structure principle block diagram (View)

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Over voltage buffer protection circuit in the process of IGBT switching

Published:2011/4/8 1:23:00 Author:may | Keyword: Over voltage, buffer protection, IGBT switching

Over voltage buffer protection circuit in the process of IGBT switching
(a) C buffer circuit (b) RC buffer circuit (c) RCVD buffer circuit (d) Discharge blocking buffer circuit (View)