描述

交流接觸器控制異步電動機的主電路、控制電路和有關(guān)的波形圖。接觸器的結(jié)構(gòu)和工作原理與繼電器的基本相同，區(qū)別僅在于繼電器觸點的額定電流較小，而接觸器是用來控制大電流負載的，例如它可以控制額定電流為幾十安至幾千安的異步電動機。按下起動按鈕SBl，它的常開觸點接通，電流經(jīng)過SBl的常開觸點和停止按鈕SB2、作過載保護用的熱繼電器FR的常閉觸點，流過交流接觸器KM的線圈，接觸器的銜鐵被吸合，使主電路中的3對常開觸點閉合，異步電動機M的三相電源被接通，電動機開始運行，控制電路中接觸器KM的輔助常開觸點同時接通。放開起動按鈕后，SBl的常開觸點斷開，電流經(jīng)KM的輔助常開觸點和SB2、FR的’常閉觸點流過KM的線圈，電動機繼續(xù)運行。KM的輔助常開觸點實現(xiàn)的這種功能稱為“自鎖”或“自保持”，它使繼電器電路具有類似于R-S觸發(fā)器的記憶功能。

在電動機運行時按停止按鈕SB2，它的常閉觸點斷開，使KM的線圈失電，KM的主觸點斷開，異步電動機的三相電源被切斷，電動機停止運行i同時控制電路中KM的輔助常開觸點斷開。當停止按鈕SB2被放開，其常閉觸點閉合后，KM的線圈仍然失電，電動機繼續(xù)保持停止運行狀態(tài)。圖1.3給出了有關(guān)信號的波形圖，圖中用高電平表示1狀態(tài)(線圈通電、按鈕被按下)，用低電平表示0狀態(tài)(線圈斷電、按鈕被放開)。

圖1.3中的控制電路在繼電器系統(tǒng)和PLC的梯形圖中被大量使用，它被稱為“起動-保持-停止”電路，或簡稱為“起保停”電路。

歐美品牌停產(chǎn)的，常用的“PLC”備品備件

我司產(chǎn)品應(yīng)用于以下領(lǐng)域：

1,《發(fā)電廠DCS監(jiān)控系統(tǒng)》

2,《智能平鋼化爐系統(tǒng)制造》

3,《PLC可編程輸送控制系統(tǒng)》

4,《DCS集散控制系統(tǒng)》
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5,《智能型消防供水控制系統(tǒng)》

6,《化工廠藥液恒流量計算機控制系統(tǒng)》

7,《電氣控制系統(tǒng)》造紙,印染生產(chǎn)線,變電站綜合自動化控制系列

本特利，英維思，伍德沃德，?？怂共_、西屋、瑞恩、施耐德莫迪康、ABB、AB、西門子、摩托羅拉、GE發(fā)那科、安川、博世力士樂，ACSO，力士樂等各大品牌的DCS系統(tǒng)配件，機器人系統(tǒng)配件，大型伺服系統(tǒng)備件。

NEW LUBE DEVICES REO156-26 AUTO LUBRICATOR/OILE?R 120V

PAIR PIONEER 450W IMPP SUBWOOFERS/SPEA?KERS WITH BOX

CASE 4000 MURATA CERAMIC CAPACITORS 250V AMMO PACKS

TIME MARK VOLTAGE MONITOR AC260B W/ENCLOSURE CABLES+

TIME MARK 3-PHASE MONITOR A258B KIT W/ENCLOSURE CABLES

CASE GENUINE MONARCH 1136 RED PRICE GUN LABELS WITH INK

NEW 1000’GENESIS 24/3PR CAT3 CMR/FTR VOICE/DATA CABLE

BOX OF 100 NEW BUSS BK/MDL-BV-5 FUSES 5A 250V MDV/MSV

NICE GRS A62-308 RAILROAD RELAY SWITCH/SIGNAL?1985

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2 NEW SIEMENS 500-633440 2 SLOT CC-2 MODULE CARD CAGE

USED IBM 73P0780 ThinkCentre A52 type 8157 System Board

24x 300’DUAL SIDED COLD LAMINATE/LAMINA?TION DL503-300

BRAND NEW AND FRESH….DIRECT THERMAL PAPER COMPATIBLE

NEW JOHNSON CONTROLS M9106-AGA-2 FLOATING ACTUATOR

PHILIPS COLOR KINETICS COLORREACH SPREAD LENS W/BEZEL

NEW DRAPER LVC-III PROJECTION SCREEN CONTROL MODULE

NEW SIEMENS 6SE6400-2FB00 MICROMASTER 4 EMC FILTER

NEW KIDDE XV CONTROL SYSTEM VALVE ACTUATOR 120042-001

QTY 6 175W ED17 CLEAR METAL HALIDE BULBS MP175/U/MED

9 OSRAM 1000W HALOGEN G9.5 DISPLAY/OPTIC LAMPS/BULBS

1969 JIM BEAM LAS VEGAS/HOOVER DAM DECANTER SEALED

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AO SMITH CONDENSER FAN MOTOR 1/5 HP ARMSTRONG LENNOX

QTY 10 NEW SENTRION HVAC LOW PRESSURE SWITCH ILPS-018

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16 NEW MCT MENARD COMPETITION RACING ENGINE LIFTERS?

NEW XENON HIGH PRESSURE ARC LASER LAMP W/BRASS FITTINGS

GENUINE ALBRIGHT SW180-222 24V DC CONTACTOR 828/36002

NEW BOTTLE GENUINE XEROX iGEN3 5R706 CYAN DEVELOPER

NEW BOTTLE GENUINE XEROX iGEN3 5R671 MAGENTA DEVELOPER

NEW GENUINE XEROX iGEN3/4 505S00003 MAGENTA DEVELOPER

NEW GENUINE XEROX iGEN3/4 505S00004 YELLOW DEVELOPER

NEW GENUINE XEROX iGEN3 5R650 YELLOW DEVELOPER

NEW BOTTLE GENUINE XEROX iGEN3 5R705 BLACK DEVELOPER

QTY 5 175W ED17 CLEAR METAL HALIDE BULBS MH175/U/MED

50 SYLVANIA 3157K TURNING SIGNAL/PARKING LAMPS/BULBS

QTY 20 NEW 9/16 x 1/2 STEEL HYDRAULIC ELBOW FITTINGS

DELTA ARZO T11866 THREE FUNCTION DIVERTER 3-PORT TRIM

NEW VON-DUPRIN EPT-10 SP28 SILVER POWER TRANSFER EPT10

NEW PULL BOX 1000’CCI 22/4 SIGNAL/ALARM/SE?CURITY CABLE

NEW LIFECYCLE 95R ENGAGE/INSPIRE USB/IPOD INTERFACE

NEW GOLIATH ANTENNA ATA 25-022A

2 NEW TITAN FP MERV 11 1000 CFM INDUSTRIAL AIR FILTERS

NEW A&M INSTRUMENTS 495 SWITCHBOARD METER COUNTS/SECOND

NEW 700’SPOOL CORNING OPTICAL CABLE SCA326/X 4 SME

12 NEW ACDELCO PF13/5579164 DURAGUARD OIL FILTERS

10,000 FOOD SERVICE/SALON POLY GLOVES FOODSERVICE LARGE

6 NEW DEUTSCH 24-PIN CONNECTORS/PLUGS DRC26-24S/24SA

NEW SURVEYOR HVAC SENSOR PACK AIRFLOW-DISCHAR?GE-RETURN+

NEW FERGUSON BEAUREGARD iNODE TLM PROBE PCB 100411-02

QTY 25 NEW JIC TO O-RING 9/16 HYDRAULIC ELBOW FITTINGS

20 NEW JIC FEMALE+MALE 9/16 HYDRAULIC ELBOW FITTINGS

NEW ADVANTECH PCA-6108E 8-SLOT BACKPLANE IPC-6908/6608

72 ROLLS FILAMENT/STRAPPING TAPE 12mm x 55M/60 YARDS

50 ROLLS NCR 856911 THERMAL RECEIPT PAPER 3-1/8 x 230′

SIGMA SPECTRUM IV WIRELESS BATTERY MODULE W/TRANSMITTER

12 NEW UNITS AVAILABLE,FREE SHIPPING!

NICE AMGLO KEMLITE APH-6841 LAMP/BULB

400’SUPERIOR ESSEX ADP-S OUTDOOR NETWORKING/DSL CABLE

1970 JIM BEAM MANITOWOC SUBMARINE WWII DECANTER SEALED

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1971 JIM BEAM LONDON BRIDGE/HAVASU CITY DECANTER SEALED

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KIDDE KITCHEN FIRE SYSTEM MANUAL PULL BOX WK-875572-000

STELLAR ORBCOMM ST2500 SATELLITE TRANSCEIVER 166STR

NEW URB Cylindrical Roller Bearing NJ 408 MC3S0 4-1/4

4-GAL STEAMETTE STEAM CARPET LIQUID EXTRACTION CLEANER

NEW Dell PowerEdge 6950 4U Server Rapid Rail Kit 0TW147

PARKER THERMOSTATIC EXPANSION VALVE 040289-01 R407C/R22

BROOKS LOI INTERFACE 4800 SERIES FLOW METER/CONTROLLE?R

GALLON PRENTOX PYRONYL INSECTICIDE ROACHES/ANTS/SP?IDERS

NEW ENLIN STAINLESS STEEL FLANGE A/SA182 F316L/316 1

10 NEW GE ENL 12V 50W BULBS/LAMPS PROJECTION/CAMERA

GEN.LEXMARK 12A5845 HY TONER OPTRA T610/T612 12A5745

QTY 100 SCP 209-AL SNAP COAXIAL WALL PLATE CONNECTORS

BLR EMPLOYMENT LAW EASY TRAINER VERSION 2.0 POWERPOINT

NEW CROW MAGIC MD-01 SINGLE DOOR ACCESS CONTROLLER

VIMEC 433.92MHZ REMOTE CONTROL 4-WHEELCHAIR/ST?AIR LIFT?

NEW PHILIPS HD HDMI/CIRCUIT BOARD AS SSB BASIC LC08SP

MODEL RC-1C VOLTAGE REGULATOR/CONTR?OLLER 400V-1200V

10 NEW CONMED ELECTROSURGICAL PENCILS W/HOLSTER 130318

IBM BLADECENTER MEDIA TRAY 31R3305 FOR CD/DVD DRIVE USB

QTY 6 NEW PHILIPS 100’CAT5E NETWORK CABLES RJ45 GRAY

KIDDE 83-844908-000 DISCHARGE ADAPTER KIT Co2 SYSTEM

NEW OPW AUTOMATIC UNLEADED FUEL PUMP NOZZLE 11AP-0500

MOTOROLA RAD4010ARB ROOF MOUNT VHF ANTENNA 136-174 MHZ

NEW CASE BULK TONER 26.4 LBS OEM IBM INFOPRINT 4100 1R

NEW CONTACT-O-MAX 5 REMOTE CONTROL HOG/BOAR BREEDING

2 NEW ESTERNA SWIMMING POOL INFLATABLE LOUNGE CHAIRS