英国R.R.公司MM74灭磁开关简介

MM74直流灭磁开关

英国R.R.(Rolls-Royce)公司 型号：MM74 ，双断口 额定电压3200V 最大弧压6400V 额定电流6000A 最大开断电流50kA 带常闭放电触头。

MM74 MM74 High Speed DC Circuit Breaker

The MM74 high-speed DC circuit breaker has been

designed specifically to meet the system requirements of the DC substation switchgear for controlling the power supplies to heavy rail transit systems, and complies with requirements of ANSI C37.14-1992 and C37.16-1980. lt is also suited to the special applications of other fields as follows:-

Generator main field circuit breaker duty

Thyristor convertor-controlled motors Rolling units in steelworks Electrolytic plants Mine winders

This truck-type withdrawable circuit breaker has been developed from our long established panel and pedestal-mounted circuit breakers which have been in service since 1936.

Main Features ? ? ? ? ? Up to 12000A rating Fully interlocked Metalciad construction Top or bottom cable entry Over 50 years experience in DC switchgear

Rated voltage Rated normal currents

800, 1600, 3200V 4000, 6000, 8000, 12000A

Short circuit interruption rating 800V up to 250kA,1600V up to 150kA,3200V up to 50kA