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c.安装简单、使用方便、维护成本大大降低。
d.机械特性好、动态响应速度快、可提高控制系统的调节品质。
e.风机、泵类等高耗电设备采用变频调速后可降低耗能、节约成本、提高效率。
二、变频装置原理
变频电动执行机构是由变频装置（变频器）和电动机组成的可调速拖动机构，电动机的转速和转向由变频装置控制，按照生产工艺的要求工作。其理论依据是下面公式：
n＝no（1-s）
no=60f／p
其中：
n——电动机转速
no——同步转速
s——滑差
f——输入电压频率
D——电动机极对数
从上面公式看出，改变电动机转速的方法有三种：一是改变滑差：二是改变电动机极对数；三是改变输入电压频率。通过引入变频装置把固定的电网频率转换成电动机所需要的频率来实现电动机的调速就是变频电动执行机构工作的理论基础。
DSQC327A 变频装置一般分为交一交、交一直一交两种实现方式。交一交型变频器的调节范围小、功率因数低、谐波污染大。现在的大部分变频装置都采用交一直一交的实现方式，其主要构成分四部分：整流器、滤波器、逆变器和以CPU为核心的控制保护部分。
整流器采用可控元件接成三相全控桥，把输入的三相交流电变成电压可调的直流电。
滤波器主要是为了获得较为平直的直流电、吸收电动机回馈的能量实现紧急刹车制动功能。
逆变器采用"门极可关断晶闸管"GTO、"大功率晶体管"GTR、"绝缘栅双级型晶体管"IGBT等元件，采用脉宽PWM调制或矢量控制等方式将直流电逆变为频率可调的交流电。
以CPU为核心的控制保护部分是整个变频装置的指挥中心、其通过输入CPU的软件程序来完成控制、保护等各种功能，并且实现与DCS、PLC及其它控制系统的接口。
变频装置按其工作电压还有高压、低压之分，高压变频器又可分为直接高压型和高一低一高型。各种类型的变频器有不同的应用场合，即使是相同类型的变频器因其技术上的差别也有着不同的品质和价格。因而在变频电动执行机构的使用中要科学的选择变频器和电动机，力求最好的性能价格比。
NIB* MARS 12005 MOTOR RUN CAPACITOR 370VAC 50/60 HZ (BIN30)
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C&D VALVE INTERNAL TEMP READING TOOL CD 3940 DIGITAL THERMOMETER & VALVE (T3)
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ALLEN BRALDEY SLC 500 INPUT MODULE 1746-IA16 SERIES C 85-132VAC 50/60HZ (W1-1)
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USED BAILEY BCN23215150 PRESSURE TRANSMITTER 3600 PSI 4-20mA 13-42 VDC (Q4)
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MTI OEM 591595-005 18GB DISK W/ SLED 7200 RPM CVD, SCA REV 6246 MOD SS-CAR (YY2)
ALLEN BRADLEY 800H-BK6 PUSH BUTTON ASSEMBLY STATION (270)
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NEW** MICRO MOTION 026791-9721 PROCESSOR BOARD (331)
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NIB* MOTOROLA MULTI-UNIT HTN9005 SERIES MULTI-UNIT RADIO CHARGER (N8)
NIB* SHIMADEN DIGITAL INDICATOR SD10 110-120/220-240?VAC (260)
FLUKE TRANSFER STANDARD MODEL 540B W/ FLUKE PLUG-IN VOLTAGE UNIT A54-2 (ZZ4)
NNB** HONEYWELL L404B PRESSURETROL SWITCH L404B12X3 PRESSURE SWITCH (O2)
NEW* GE SB-10 PUSH or PULL 16SB10 226A9448G1X2 LATERAL SWITCH W/ COVER (F7)
NEW** GE SB-10 - 12" PUSH/PULL 16SB10 226A9725G1X2 LATERAL SWITCH W/ COVER (F7)
NEW TRANE X13650140-01 PCB PROCESS CONTROL PANEL (TT4) DSQC327A
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GOOD** BALDOR MA7080BF SOLID STATE TYPE M DRIVE STARTER 50HP 460V 3PH 60HZ (Q7)
DEI DTS-1500A CONTROL CHASSIS DTS-1500A 110VAC 20AMP 50/60HZ (OR35)
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