6ES7421-7DH00-0AB0 框架接口

6ES7421-7DH00-0AB0 框架接口

高压软起动

社会发展是有阶段性的。在不同阶段，人们的生产手段、生产工具和生活用品都有很大的不同。上世纪80～90年代，中国的经济实力尚较薄弱，当时的小水泥和小钢铁发展很快，1000kW～4000kW电机的应用增长很快，与当时的经济基础相适应的液态起动装置出现，它经济实用，解决了电机起动中的一些问题。对当时的经济发展起到了的作用。到世纪之交时期，中国经济实力已有较大的发展，生产手段和生产工具亦有了较大发展，电机容量也有了很大增长，人们开始不满足液态起动装置的低性能，于是晶闸管串联式（固态）软起动装置的应用开始增加，继而又出现了开关变压器式软起动装置和磁饱和电抗器式（磁控）起动装置，变频装置用于电机软起动的情况也越来越多，当前这四种产品是大型电机起动市场的主流产品，液态起动装置则应用在小型（5000kW以下）电机上较多。另外，两种老式起动方法（自耦变压器和变压器-电动机组）也常常出现在20000kW以下电机的起动上。

大型电机驱动的设备一般都是企业的核心设备，直接影响企业的生产状况，因此人们应该对其起动给予特别的关注，合理的选择起动装置将给企业带来很大的经济效益。但是电机起动技术毕竟不是一个企业的核心技术，许多企业的电气工作者很少有时间来研究各种起动方法之间的差别，往往会造成不恰当的选择，有时甚至不得不做出第二次选择，给企业造成不应有的损失。因此，如实地说明各种起动方法的性能及其差别是非常重要的。为此我们在这方面做抛砖之尝试，如有不完善和不妥之处，望不吝添金加玉。

引起电网电压波动，影响同电网其它设备的运行

交流电动机在全压直接起动时，起动电流会达到额定电流的4~7倍，当电机的容量相对较大时，该起动电流会引起电网电压的急剧下降，影响同电网其它设备的正常运行。

软起动时，起动电流一般为额定电流的2~3倍，电网电压波动率一般在10%以内，对其它设备的影响非常小。

⒉对电网的影响

对电网的影响主要表现在两个方面：

①超大型电机直接起动的大电流对电网的冲击几乎类似于三相短路对电网的冲击，常常会引发功率振荡，使电网失去稳定。

②起动电流中含有大量的高次谐波，会与电网电路参数引起高频谐振，造成继电保护误动作、自动控制失灵等故障。

软起动时起动电流大幅度降低，以上影响可完全免除。

YOKOGAWA 260310LSSJ     260310LSSJ

YOKOGAWA 260310LSSJ    260310LSSJ

YOKOGAWA 260-320LSZZ    260320LSZZ

YOKOGAWA 260-320-MTZZ     260320MTZZ

YOKOGAWA 260-320-MTZZ    260320MTZZ

YOKOGAWA 260-320-XSXS     260320XSXS

YOKOGAWA 260321SFSF9 **NIB**

Yokogawa 260324ECNT 0-50 DC Ammeter

YOKOGAWA 260324ECRX     260324ECRX

YOKOGAWA 260324ECRX   260324ECRX

Yokogawa 260338PN-PN9/JAA 100-150VDC Voltmeter

Yokogawa 260340LSRL1 0-5 Amps 50-400 Hz 200 AC Amperes Meter

Yokogawa 260344PZPZ1 Scale: 0-150 VAC Voltmeter

YOKOGAWA 260400FAFA-9JBS     260400FAFA9JBS

YOKOGAWA 260400FAXX    260400FAXX

Yokogawa 260400KGKG9JAU Stylist 4 1/2" Motor Load Panel Meter 60-300 MAAC      

YOKOGAWA 260400KGKG-E9000-1     260400KGKGE90001

YOKOGAWA 260430PZPZ     260430PZPZ

Yokogawa 260439FTZZ1 260-439-FTZZ 4 1/2" iron vane mod meter 3.7MA

Yokogawa 260444PZPZ 0-150VAC AC Voltmeter Scale

Yokogawa 260444PZPZ 0-150VAC Scale AC Voltmeter

Yokogawa 260444SJSJ1JAB/UL AC Voltmeter

YOKOGAWA 260450ANAN9     260450ANAN9

Yokogawa 261224ECPB9 White 75 DC Amperes METER

YOKOGAWA 261339LSZZ9     261339LSZZ9

YOKOGAWA 264220MTMT-010656    264220MTMT010656

Yokogawa 264320PZPZ9 0-150 VDC Voltmeter

Yokogawa 264324ECRL 0-200 DC Ammeters

Yokogawa 264324GBRX9 0-300A Ammeter

Yokogawa 264350ANAN9 120V Frequency Meter

YOKOGAWA 2652-02 (MT120) Manometer

YOKOGAWA 2655-22   265522

Yokogawa 270710 Electronic Galvanometer

Yokogawa 270710 Portable Electronic Galvanometer

Yokogawa 270800 Galvanometer

Yokogawa 270800 Galvanometer

Yokogawa 2709 Electronic Galavanometer (free shipping)

YOKOGAWA 2743 STANDARD CURRENT SHUNT 2 Amp, 100 mV -- MODEL 274301

Yokogawa 275200 Precision Double Bridge, 0.03 to 0.05%

YOKOGAWA 2755 WHEATSTONE BRIDGE

Yokogawa 275597 Portable Wheatstone Bridge, 1.000 ohm to 10.00 M ohm

Yokogawa 276800 Precision Wheatstone Bridge

Yokogawa 2769-10 0.1mΩ Portable Double Bridge

Yokogawa 276910 Portable Double Bridge

Yokogawa 2769U Portable Double Bridge, Refurbished

Yokogawa 2786 Decade Resistance Box Instruction Manual

Yokogawa 278610 Decade Resistance Box, 0.1-111, 111 ohm (6 Decade Dial

Yokogawa 278620 Decade Resistance Box, 1-111 , 111 ohm (6 Decade Dials

YOKOGAWA 278A2184BPP1 PANEL METER *      IN A BOX*

Yokogawa 279101 Slide Resistor, 4,800 ohm

Yokogawa 279102 Slide Resistor, 1,400 ohm

Yokogawa 279103 Slide Resistor, 600 ohm

Yokogawa 279105 Slide Resistor, 170 ohm

Yokogawa 279108 Slide Resistor, 39 ohm

Yokogawa 279110 Slide Resistor, 10 ohm

Yokogawa 279112 Slide Resistor, 4.7 ohm

Yokogawa 2792(0.001ohm)

Yokogawa 2792(0.01ohm)

Yokogawa 279209 Standard Resistor, 100 k ohm Nominal Value, 3 Terminal

Yokogawa 279210 Standard Resistor, 1 M ohm Nominal Value, 3 Terminal

Yokogawa 2792A01 2792 Series Standard Resistor, 0.001 ohm Nominal Valu

Yokogawa 2792A02 2792 Series Standard Resistor, 0.01 ohm Nominal Value

Yokogawa 2792A03 2792 Series Standard Resistor, 0.1 ohm Nominal Value,

Yokogawa 2792A04 2792 Series Standard Resistor, 1 ohm Nominal Value, 4

YOKOGAWA 2792A-04 standard resister 1ohm 30ppm

YOKOGAWA 2792A-04 standard resister 1ohm 30ppm

Yokogawa 2792A05 2792 Series Standard Resistor, 10 ohm Nominal Value,

Yokogawa 2792A06 2792 Series Standard Resistor, 100 ohm Nominal Value,

Yokogawa 2792A07 2792 Series Standard Resistor, 1k ohm Nominal Value,

Yokogawa 2792A08 2792 Series Standard Resistor, 10k ohm Nominal Value,

Yokogawa 2793 Decade Resistance Box

YOKOGAWA 2793 DECADE RESISTANCE BOX 279301 NICE ! W

Yokogawa 279301 Decade Resistance Box

Yokogawa 279301 Decade Resistance Box, 1 M ohm

Yokogawa 279303 Decade Resistance Box, 100 M ohm

Yokogawa 279303 Resistance Decade Box

Yokogawa 2805 Digital Voltmeter Service Manual w/ Schematics Rev 3/73

Yokogawa 2805 Digital Voltmeter Service Manual w/ Schematics. c 8/72. copy

Yokogawa 286111FA-FA8/JAC Panel Meter 0-1 MADC(H) 0-100

YOKOGAWA 286112FAFA   286112FAFA

YOKOGAWA 286-113-HJZZ     286113HJZZ

Yokogawa 286119CYZZ8 286-119-CYZZ 0-50UADC DC Ammeter

YOKOGAWA 286-129-ECZZ8   286129ECZZ8

YOKOGAWA 287-011-NTNT   287011NTNT

YOKOGAWA 287051NTNT   287051NTNT

YOKOGAWA 287112CYCY8 PANEL METER DC MICROAMPERES RIG 50-0-50HA ***NIB***

YOKOGAWA 287113CYCY8JBB     287113CYCY8JBB

Yokogawa 287119 FAZZ8 DC Ammeter Vertical 0-1.0 Milliamperes DC Current

YOKOGAWA 287119FAZZ     287119FAZZ

YOKOGAWA 287-121-GBSF   287121GBSF

YOKOGAWA 2871991/61RW0991 17MM X 64MM PH ANALOG PANEL METER SENSOR

Yokogawa 288119HEZZ8 288-119-HEZZ DC Ammeter 4-20mA      

YOKOGAWA 288123ECNG     288123ECNG

YOKOGAWA 288123ECNG   288123ECNG

YOKOGAWA 288-1988-68RY0503   288198868RY0503

YOKOGAWA 288-1989   2881989

YOKOGAWA 288-1990-60RY0412   288199060RY0412

YOKOGAWA 288-1990-60RY0426   288199060RY0426

YOKOGAWA 288-1990-60RY2781    288199060RY2781

YOKOGAWA 29324   29324

Yokogawa 2B6 Panel Meter 50-0-50 8920HD DC Microamperes Amps      

Yokogawa 2-MR-33 Chart Recorder

YOKOGAWA 2-Wire Conductivity Resistivity Analyzer Transmitter SC202G-A-E/U

YOKOGAWA 3.0W 120V 60H TIME METER NIB 240311AAAB

Yokogawa 3.5" DC Current Panel Meter 0-5A 250300LSLS

Yokogawa 3.5" Panel 75Vdc DC Voltmeter Part # 2944-864-00 w/ Zero Adjuster

YOKOGAWA 3/4" NPT 18' 12MM CONDUCTIVITY SENSOR SC41-SP26      

YOKOGAWA 300-0002    3000002

YOKOGAWA 300-0-300 PANEL METER 7VDPX032AM04 *      IN BOX*

YOKOGAWA 30031A Digital Clamp on Meter       with Warranty

YOKOGAWA 30032A Digital Clamp on Meter       with Warranty

Yokogawa 3015-0627 All-in-one Refrigerant Leak Detector - R12/r134a (30150627)

Yokogawa 3021 Pen Recorder Plotter

YOKOGAWA 302211   302211

Yokogawa 3025 X-Y Chart Oscillograph Recorder Time Base Data Plotter Logger

YOKOGAWA 302523   302523

Yokogawa 3057 305722 Portable Recorder

YOKOGAWA 30800224 3 PACK B9588KJ

Yokogawa 3087 Portable Hybrid Chart Recorder 308764, -3/D

YOKOGAWA 3087 PORTABLE HYBRID RECORDER - SOLD AS IS

YOKOGAWA 3087-64 PORTABLE DIGITAL HYBRID CHART RECORDER

YOKOGAWA 3087-64 PORTABLE HYBRID RECORDER - SOLD AS IS

Yokogawa 3-1/2" 0-200VAC Analog Panel Gauge Panel Meter 250330RLRL 250-330-RLRL

Yokogawa 3-1/2" Horizon Line 0-300 DC Amperes Analog Panel Meter 261 324 ECRX

Yokogawa 3-1/2" Panel Meter Gauge 0-1000 AC Amps 0-1 kA-Ammeter 0-5A Rating NIB

Yokogawa 3-1/2" Panel Meter Gauge 0-1500 AC Amps 0-1.5kA-Ammeter 0-5A Rating NIB

Yokogawa 3-1/2" Panel Meter Gauge 0-2000 AC Amps 0-2 kA-Ammeter 0-5A Rating NIB

Yokogawa 3-1/2" Panel Meter Gauge 0-2500 AC Amps 0-2.5kA-Ammeter 0-5A Rating NIB

Yokogawa 3-1/2" Panel Meter Gauge 0-4000 AC Amps 0-4kA -Ammeter 0-5A Rating NIB

YOKOGAWA 3-1/2” Dual Scale Panel DC Ammeter

YOKOGAWA 3213-04   321304

YOKOGAWA 321342   321342

Yokogawa 321345 Insulation Tester

Yokogawa 3213A Insulation Tester BR

Yokogawa 322610 Current Sensor

Yokogawa 3226-10 Leakage Current Tester (AC/DC)

Yokogawa 322710 (Test Box for 3226)

Yokogawa 3228 Clip-On Ammeter

YOKOGAWA 3235 Analog Earth Tester

Yokogawa 3235 Earth Tester Instruction Manual 2nd ed 10/72

Yokogawa 3235 Earth Tester Instruction Manual 2nd ed 10/72. copy

Yokogawa 325400

Yokogawa 3296 - 01 Optical Probe & Sensor

YOKOGAWA 3298 329811 MULTIMEDIA DISPLAY TESTER

YOKOGAWA 3298 329821 Colour MULTIMEDIA DISPLAY TESTER

YOKOGAWA 3298F / 392802-J Colour MULTIMEDIA DISPLAY TESTER

YOKOGAWA 33 0-30-60/5A AM METER       IN BOX

Yokogawa 33" Temperature Sensor & Recorder Unit Stainless Steel Case

Yokogawa 336637 Panel Meter 0-100ADC Range 0-100DCA      

Yokogawa 336637-800 Panel Meter FS=200MV 0-800A DC Range      

Yokogawa 3606 Sound Level Meter

Yokogawa 3640-13-1-M Power Line Monitor (High-function type)

YOKOGAWA 3655E ANALYZING RECORDER

YOKOGAWA 3655E ANALYZING RECORDER 115VAC 60HZ ***XLNT***

YOKOGAWA 3659-41   365941

YOKOGAWA 3659-42   365942

YOKOGAWA 3659-61 PT,CT 2ch 600V 10A Line Power unit

YOKOGAWA 370166 LR8100E Multiple Pen Recorder

YOKOGAWA 371122-B-O/D   371122BOD