AUTOMATIC TRANSFER SWITCHES自动转换开关.pptVIP

Overview What is Selective Coordination? Proper Selective Coordination is becoming more and more of an engineering consideration and is being enforced more often… NEC 2008 –Verbiage on Selective Coordination One-line Selective Coordination More on Selective Coordination Code Requirements 2005 Code Adoption 2008 Code Adoption Code Rulings Exceptions to Code RulingsRefer to IEEE handout “Selective Coordination versus Arc Flash…” page 12 Exceptions to Code Rulings (cont.) Arc Flash ConsiderationsRefer to IEEE handout “Selective Coordination versus Arc Flash…” page 10 UL 1008 Withstand Test 34.1 When tested under the conditions described in 34.2 – 34.15, a transfer switch shall withstand the designated levels of current until the over-current protective devices open or for a time as designated in 34.3. At the conclusion of the test: The switch shall be capable of being operated by its intended means; The fuse mentioned in 34.14 shall not open, There shall be no breakage of the switch base to the extent that the integrity of the mounting of live parts is impaired, The door shall be prevented by its latch, without bolt or lock installed therein, from being blown open, and deformation of the door alone is not determined to be unacceptable; No conductor shall have pulled out of a terminal connector and there is no damage to the conductor insulation or the conductor (see 41.56); and For a plug in or draw out unit, the point of contact is to be the same both mechanically and electrically as before the test. UL 1008 Closing Test 36.1 When tested in accordance with 36.2, a transfer switch shall comply with the requirements in 34.1(a) –(f). 36.1 Revised September 18, 1996 36.2 The sample for this test is to be that used for the withstand test. Test procedures and conditions for the closing test are to be as described in 34.3 – 34.19. The switch is to be closed on the circuit. 36.3. The test (for close on) current shall be the same as that used in the withstand test. U