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隔离变压器的二次端绕组间的电压是大于selv的限值的,那么这段电路是接地或者未接地的次级危险电压电路。如果次级危险电压电路与初级仅有基本绝缘的时候,才要求这个次级危险电压电路与SELV满足附加绝缘或者加强绝缘(不是满足基本绝缘!)。(见IEC/EN60950-1 table 2H note C). O; {- h0 J2 D0 q# K
如果SELV电路由次级危险电压电路供电,只要这个次级危险电压电路与初级是加强或双重绝缘即可。
' _% r+ ?$ S; ~( pIf an SELV CIRCUIT is derived from a HAZARDOUS VOLTAGE SECONDARY CIRCUIT, and the
/ q$ i, E+ B7 l( J' rHAZARDOUS VOLTAGE SECONDARY CIRCUIT is separated from the PRIMARY CIRCUIT by DOUBLE4 o* y8 P7 e. [6 f0 t+ e \5 o/ W
INSULATION or REINFORCED INSULATION, the SELV CIRCUIT shall remain within the limits given in& q2 t, b/ x$ S5 b ?5 X
2.2.3 under single fault conditions (see 1.4.14). |
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