PM511V08/3BSE01180R1安全仪表系统
变压器保护的选择。公告1489-M断路器为UL 489第7.1.4.2段规定的“非100%额定值”。因此，如果与连续负载一起使用，断路器的额定值应不超过80%。线路和负载可能颠倒。公告1489-M断路器可为底部馈电。1489-M电路断路器罗克韦尔自动化出版1492-SG123D-EN-P-2014年3月13 HACR评级公告1489-A断路器被评为UL 489第6.7段规定的加热、空调和制冷断路器，可用于此类应用。SWD额定值公告1489-M断路器（0.5…20 A）的额定值为开关负载（SWD），因此可用于将荧光灯负载切换至最大电流和电压。公告1489-M断路器的额定值为UL 489第8.6段中规定的限流断路器。公告1489-M线路具有比传统断路器更有效地实现短路中断的能力。在传统的断路器中，所需的短路中断时间约为交流正弦波的一个或两个半周期。当触点断开时，产生的电弧继续燃烧，直到电流水平通过零。由于接触间隙的宽度不足，电弧可能再次点燃。在电弧熄灭之前流动的电流产生与故障电流I2t值（通过能量）成比例的加热效果。Bulletin 1489-M设备的设计目的是大幅减少泄漏电流的量以及由此产生的泄漏能量，这些泄漏能量可能会损坏受保护的部件。公告1489-M能够在故障的前半个周期内中断短路电流。限制通流电流和能量将防止过电流的有害影响，并主要集中于避免过热和机械损坏。如果需要有序停机以尽量减少对人员和设备的危害，则基于故障或过载电路的协调系统将通过仅选择性操作最接近过电流条件的过电流保护装置来隔离。用户应选择符合此要求的设备。selection for transformer protection. The Bulletin 1489-M circuit breakers are “non-100% rated” as defined by UL 489, para 7.1.4.2. As such, the circuit breaker's rating should be loaded to no more than 80% if used with continuous loads. Line and load may be reversed. The Bulletin 1489-M circuit breaker may be bottom fed. 1489-M Circuit Breakers Rockwell Automation Publication 1492-SG123D-EN-P — March 2014 13 HACR Rating Bulletin 1489-M Circuit Breakers are rated as Heating, Air Conditioning and Refrigeration circuit breakers as defined by UL 489, paragraph 6.7 and may used in this type of application. SWD Rating The Bulletin 1489-M breakers (0.5 … 20 A) are rated as Switch Duty (SWD) and as such may be applied to switch fluorescent lighting loads up to their current and voltage maximum. Bulletin 1489-M Circuit Breakers are rated as current limiting circuit breakers as defined by UL 489, paragraph 8.6. The Bulletin 1489-M line features the ability to achieve short circuit interruptions far more effectively than conventional breakers. In conventional circuit breakers, the short circuit interruption time required is approximately one or two half cycles of an AC sine wave. When the contacts open, the resulting arc continues to burn until the current level passes through zero. The arc may re-ignite because of the insufficient width of the contact gap. The current that flows until the arc is extinguished produces a heating effect proportional to the I 2 t value (let-through-energy) of the fault current. The Bulletin 1489-M device is designed to substantially reduce the amount of let-through-current and the resulting let-through-energy that can damage protected components. The Bulletin 1489-M has the ability to interrupt short circuit current within the first half cycle of the fault. Limiting letthrough current and energy will protect against the harmful effects of overcurrent and is focused primarily on avoiding excessive heat and mechanical damage. Where an orderly shutdown is required to minimize the hazards to personnel and equipment, a system of coordination based upon the faulted or overloaded circuit is isolated by selective operation of only the overcurrent protective device closest to the overcurrent condition. The user should select devices that meet this requirement.
