关于UL 1838标准里的输出电路隔离是否要加入屏蔽线?" E7 ~" K9 E: N* j
标准里是这么说的:
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6 P K& Z$ R# A: {, zUL1838 CLAUSE 22.3 Output circuit isolation 22.3 revised August 7, 2007 22.3.1 Each output circuit shall be electrically isolated from the power unit supply circuit. Each output circuit shall not be bonded to the supply circuit equipment grounding conductor or to dead metal bonded to the supply circuit equipment grounding conductor. 22.3.1 added August 7, 2007 22.3.2 Where a transformer is used to provide isolation, the primary and secondary windings shall be: a) Mounted on separate sections of the core; b) Of a split bobbin construction with the transformer complying with the requirements for double insulation in the Reference Standards for Electrical and Electronic Equipment, UL 1097, or UL 2097; or c) separated by a shield of copper that is at least 0.002 inches (0.051 mm) thick or brass minimum 0.005 inch (0.127 mm). 22.3.2 revised August 7, 2007 22.3.3 The copper or brass shield form of isolation specified in 22.3.2 shall be used for a power unit marked as suitable for operating a submersible luminaire or pump. 22.3.3 added August 7, 2007 22.3.4 A connection shall be made between the shield and ground by means of a bonding lead sized at least as large as the conductor used to supply the primary winding magnet wire, and shall be no smaller than 18 AWG (0.82 mm2). 22.3.5 Transformers used for output circuit isolation in an electronic power unit shall comply with 22.3.1 – 22.3.4. Other means to isolate the primary from the output circuit in an electronic power unit, such as optical isolators that comply with the Standard for Optical Isolators, UL 1577, shall be provided where separation through barriers or electrical spacings is not provided.
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