BENTLY NEVADA 990-04-50-02-00

BENTLY NEVADA 990-04-50-02-00

BENTLY NEVADA 990-04-50-02-00

联系人:刘经理

电话:0592-5580706   15359273796

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.
异步电动机的制动方法有哪些?各自有何特点?速度继电器用于哪种制动方法? 
异步电动机的制动方法一般有两类:机械制动和电气制动。机械制动常用的方法有:电磁抱闸和电磁离合器制动。常用的制动方法有能耗制动、反接制动和回馈制动。
反接制动的优点是:制动力强，制动迅速。缺点是:制动准确性差，制动过程中冲击强烈，易损坏传动零件，制动能量消耗大，不宜经常制动。因此反接制动一般适用于制动要求迅速、系统惯性较大，不经常启动与制动的场合。
能耗制动的优点是制动准确、平稳，且能量消耗较小。缺点是需附加直流电源装置，设备费用较高，制动力较弱，在低速时制动力矩小。所以，能耗制动一般用于要求制动准确、平稳的场合。
回馈制动是一种比较经济的制动方法。制动时不需改变线路即可从电动运行状态自动地转入发电制动状态，把机械能转换成电能再回馈到电网，节能效果显著。缺点是应用范围较窄，仅当电动机转速大于同步转速时才能实现发电制动。
BENTLY NEVADA 3300/55-01-04-03-03-00-00-05-00
BENTLY NEVADA 3300/61-03-01-00-01-00-00 GK70030L
BENTLY NEVADA 3300/65 -02-01-00-00-01-01
BENTLY NEVADA 3300/65-03-01-00-00-00-01
BENTLY NEVADA 3300/70-01 
BENTLY NEVADA 3300/80 
BENTLY NEVADA 3300/80-02-00-01-00
BENTLY NEVADA 3300/90-00-00 TE619161 TC611040
BENTLY NEVADA 3300-01-01-00
BENTLY NEVADA 330001-02-00
BENTLY NEVADA 3300-01-3300-25
BENTLY NEVADA 330003-01-00
BENTLY NEVADA 330003-01-02
BENTLY NEVADA 330010-01-02
BENTLY NEVADA 3300-10-01-02-00
BENTLY NEVADA 3300/1/1
BENTLY NEVADA 3300-16-02-05-01-00-00-00
BENTLY NEVADA 330100-50-00 
BENTLY NEVADA 330100-90-05 
BENTLY NEVADA 330101-00-20-05-02-00
BENTLY NEVADA 330103-00-09-15-05-00
BENTLY NEVADA 330104-00-08-10-02-00
BENTLY NEVADA 330104-00-08-10-02-05
BENTLY NEVADA 330104-00-10-50-02-00
BENTLY NEVADA 330104-00-13-50-02-00
BENTLY NEVADA 330104-09-19-10-02-00
BENTLY NEVADA 330106-05-30-05-02-00
BENTLY NEVADA 330180-91-00
BENTLY NEVADA 330180-X0-05
BENTLY NEVADA 3303/03-02-01 GK704489
BENTLY NEVADA 330300-90-00
BENTLY NEVADA 330400-01-00
BENTLY NEVADA 330500-04-00 VELOMITOR
BENTLY NEVADA 330850-90-05
BENTLY NEVADA 330900-50-05
BENTLY NEVADA 330930-045-01-00
BENTLY NEVADA 330980-50-05
BENTLY NEVADA 330980-70-00
BENTLY NEVADA 330980-71-05
BENTLY NEVADA 33180-91-05
BENTLY NEVADA 3500/15 127610-01S
BENTLY NEVADA 3500/22M
BENTLY NEVADA 3500/25 126398-01F
BENTLY NEVADA 3500/42M 138708-01
BENTLY NEVADA 3500/93 
BENTLY NEVADA 3500/94 
BENTLY NEVADA 3536-190501
BENTLY NEVADA 35mm-76683-90
BENTLY NEVADA 3600/16-02-01-00-00-00-00
BENTLY NEVADA 4X-IP65-SAR
BENTLY NEVADA 7200RVXYII
BENTLY NEVADA 72050-01-01 
BENTLY NEVADA 72102-01u
BENTLY NEVADA 72200-02-02-01-01-01-11
BENTLY NEVADA 72208-01 
BENTLY NEVADA 72300-01-04-02-03-01-01
BENTLY NEVADA 72301-03-04-01 BOARD
BENTLY NEVADA 72308-01 P601432
BENTLY NEVADA 72383-03-00-00 
BENTLY NEVADA 72400-01-04 
BENTLY NEVADA 72801-XX-02-XX-XX-XX-02-15
BENTLY NEVADA 72975-03-03-01-01-01-01
BENTLY NEVADA 77448-01S