联系人：陈小真  
Q Q ：
电话：0591- 手机：18950191660 
 传真：0591-83489960（敬请注陈小真收）
邮箱：@qq.com
地址：福州市区乌龙江大道正荣财富中心B座八层

在电动机控制接线中，主电路中装有熔断器，为什么还要加装热继电器?它们各起何作用，能否互相代替?而在电热及照明线路中，为什么只装熔断器而不装热继电器?

答:熔断器在电气线路中主要起短路保护和严重过载保护作用，而热继电器主要用于过载保护.两者不能互为代用，但可以互为补充.如果用熔断器作电动机的过载保护，为了防止电动机在启动过程中熔断器熔断，熔断器熔体的额定电流一般应取电动机额定电流的2. 5~3倍，这样即使电动机长时间过负荷50%，熔断器也不会熔断，而电动机可能因长时间过负荷而烧坏.所以不能用熔断器作过负载保护.而热继电器是利用电流的热效应来工作的，由于热惯性的影响，尽管发生短路时电流很大，也不可能使热继电器立即动作，这样就延长了短路故障的影响时间，对供电系统及用电设备会造成危害.所以也不能用热继电器作为短路保护.

对于电热及照明设备，由于负载的性质不同于电动机的拖动负载，一般来说，它们不会出现过负载现象，所以，一般不装备热继电器，而只装备熔断器，主要起短路保护作用.

IECAB01 General Purpose Cabinet －－- This cabinet houses both modules
IECAB02 General Purpose Cabinet －－- This cabinet houses termination
IECAB03 General Purpose Cabinet －－- This cabinet houses both modules
IECAB11 NEMA 4 Cabinet －－- This cabinet is rated as a NEMA 4 enclosu
IECAB12 NEMA 4 Cabinet －－- This cabinet is rated as a NEMA 4 enclosu
IECFE11 NEMA 4 Small Field Enclosure Wall Mount －－- This enclosure
IECFE12 NEMA 4 Small Field Enclosure Floor Mount －－- This enclosure
IEFAN01 Fan Assembly 120 VAC Six Fan Assembly －－- The Fan Assembly
IEFAN03 Fan Assembly 24 VDC Six Fan Assembly －－- The Fan Assembly p
IEFAN04 Fan Assembly 120 VAC Redundant Fan Assembly －－- The Fan Ass
IEFAN05 Fan Assembly 48 VDC Six Fan Assembly －－- The Fan Assembly p
IEFAN06 Fan Assembly 240 VAC Redundant Fan Assembly －－- The Fan Ass
IEMMU01 Module Mounting Unit (Rear Mounted) －－- The Module Mounting
IEMMU02 Module Mounting Unit (Front Mounted) －－- The Module Mounting
IEMMU04 Module Mounting Unit 5 Module Slots －－- Included in the NEM
IEMMU11 Module Mounting Unit (Rear Mounted) －－- The Module Mounting
IEMMU12 Module Mounting Unit (Front Mounted) －－- The Module Mounting
IEMMU21 Module Mounting Unit (Rear Mounted) －－- The Module Mounting
IEMMU22 Module Mounting Unit (Front Mounted) －－- The Module Mountin
IEPAF02 Field Power Module AC Input －－- The IEPAF02 provides 24 vol
IEPAS02 System Power Module AC Input －－- The IEPAS02 provides +5V
IEPBM01 Power Bus Monitor －－- The IEPBM01 monitors 5 VDC ａnd + -15 V
IEPDF01 Field Power Module 24 VDC Input －－-The IEPDF01 power module
IEPDF02 Field Power Module 48 VDC Input －－-The IEPDF01 provides 48V
IEPDP01 Power Distribution Panel －－-The IEPDP01 provides power Fan-
IEPDS01 System Power Module 24 VDC Input －－- The IEPDS01 receives 2
IEPDS02 System Power Module 48 VDC Input
IEPEP01 Power Entry Panel Single AC Feed －－-The Power Entry Panel c
IEPEP03 Power Entry Panel Redundant AC Feed －－- The IEPEP03 transfe
IEPEP04 Power Entry Panel Redundant 24 or 48 VDC Feed －－- The Power
IEPMU01 Power Mounting Unit Rear Mount －－- The Power Mounting Unit
IEPMU02 Power Mounting Unit Front Mount －－- The Power Mounting Unit
IIADP01 Annunciator Display Panel －－- The IIADP01 panel mounts on th
IIADP02 Annunciator Display Panel －－- The IIADP02 is the same as the
IIAKB01 Auxiliary Engineering Keyboard －－- This QWERTY keyboard plug
IIAKB03 Auxiliary Engineering Keyboard －－- For OIS40 OIS OIC41 and
IIAKB03A Auxiliary Engineering Keyboard －－- For OIS OIC43 ａnd Conduct
IIAKB04 Auxiliary Engineering Keyboard －－- For OIC42 ａnd Conductor V
IIATB01 Trackball for OIS Series 20 25
IIATB02 Trackball for OIS OIC40 OIS OIC41 ａnd OIS42
IIATB03 Trackball for Signature 42 Series
IIATB04 Trackball for Signature 12 43 ａnd Conductor VMS Signature C
IIATB05 Trackball for OIC42 OIS43 OIC43 ａnd Conductor VMS
IIATS01 Touchscreen on OIS OIC 20 ａnd 25 －－- Touch screen allows the
IIATS02 Touchscreen on OIS OIC 20 ａnd 25 －－- Use with 19 Console p
IIATS03 Touchscreen on OIS OIC 20 ａnd 25 －－- Use with 19 Console p
IIATS41 Touchscreen on OIS42 OIC42 OIS OIC43 Conductor VMS －－- Use
IIATS42 Touchscreen on OIS42 OIC42 Conductor VMS －－- Use with 19 c
IIMCL01 Multibus Communication Link Termination －－- Infi-Net Plant L
IIMCP01I Multibus Communication Processor Infinet
IIMCP01P Multibus Communication Processor Plantloop
IIMCP02 Multibus Communication Processor SCSI －－- Loop module to OI
IIMGC01 Multibus Graphics Card －－- Support for one OIS CRT For IIOIS
IIMGC02 Hi Speed Multibus Graphics Card (640 x 480) －－- Support for
IIMGC03 Hi Speed Multibus Graphics Card (1024 x 768) －－- Support for
IIMKM01 Multibus Keyboard Module －－- Keyboard electronics for IIOIS1
IIMKM02 Multibus Keyboard Module －－- Keyboard electronics for IIOIS4
IIMLM01 Multibus Loop Module －－- Communication Highway to Communicat
IIMPM01 Multibus Processor Module －－- Processor CPU Module For use w
IIMPM02 Multibus Processor Module －－- Processor CPU Module For use w
IIMRM02 Multibus Reset Module －－- Reset electronics for driver cabin
IIMSM01 Multibus Serial I O Module －－- For use with IIOIS20 25 ａnd N
IIOIS10 Operator Interface Station Series 10 －－- 1500 tags 500 tre
IIOIS20 Operator Interface Station Series 20 －－- 5000 tags 1000 tr
IIOIS25 Operator Interface Station Series 20 －－- 5000 tags 1000 tr
IIOIS30 Operator Interface Station Series 30 －－- 10 000 tags 1500
IIOIS40 Operator Interface Station Series 40 －－- The IIOIS Series 4
IIOIS41 Operator Interface Station Series 40 －－- The IIOIS Series 4
IIOIS42 Operator Interface Station Series 40 －－- The IIOIS Series 4
IISAC01 Analog Control Station －－- The Analog Control Station provid
IMAMM03 Analog Master Module －－- The Analog Master Module accepts an
IMASI02 Analog Input Module －－- The Analog Input Module provides fif
IMASI03 Analog Input Module －－- The Analog Input Module has 16 analo
IMASI13 Analog Input Module －－- The Analog Input Module has 16 analo
IMASI23 Analog Input Module －－- The Analog Input Module has 16 analo
IMASM01 Analog Input Module －－- This analog slave module processes u
IMASM02 Analog Input Module －－- This NASM02 IMASM02 accepts up to ei
IMASM03 Analog Input Module －－- This analog slave module accepts up
IMASM04 Analog Input Module －－- This NASM04 IMASM04 accepts up to ei
IMASO01 Analog Output Module －－- The NASO01 IMASO01 IMASO11 provides
IMASO11 Analog Input Module －－- This analog slave module processes u
IMASO11 Analog Output Module －－- The NASO01 IMASO01 IMASO11 provides
IMCIS02 Control I O Module －－- The Control I O Module supplies analo
IMCIS12 Control I O Module －－- The Control I O Module supplies analo
IMCIS22 Control I O Module －－- The Control I O Module supplies analo
IMCOM03 Enhanced Controller Module －－- The Enhanced Controller Modul
IMCOM04 Advanced Controller Module －－- This module has similar featu
IMCPM01 Communication Port Module
IMCPM01 Communication Port Module