The motor cooling fans in 0.4 kV low-voltage frequency conversion distributing circuits of TN systems have dis-advantageous features such as low capacity and small sectional area the corresponding cable.This paper discusses the de-sign of its distribution protection,with an emphasis on indirect contact shock prevention for distant distributing circuits.With respect to practical electric designs,the paper recommends the use of the approximate calculating formula of mini-mum ground fault current to deduce the maximum protective distribution distance for circuits with breakers or fuses as protective components.
关键词
变频回路/散热风扇/间接接触防护/接地故障保护/断路器/熔断器
Key words
frequency conversion circuit/cooling fan/indirect contact prevention/ground fault relay/circuit breaker/fuse
维普
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