UL-508C-BULLETINS-2006.pdf
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1、FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Subject 508C March 24, 2006 SUMMARY OF TOPICS The following topics were discussed at the meeting: 1. REMOVABLE COVERS GIVING ACCESS TO FUSES AND OTHER OVERLOAD PROTECTIVE DEVICES 2. CONDUCTING SHORT CIRCUIT TESTING ON DRIVES WITH SOLID ST
2、ATE DETECTION CIRCUITRY WITH ONLY ONE TYPE OF BRANCH CIRCUIT PROTECTIVE DEVICE IN ORDER TO COVER ALL BCP DEVICES 3. SIZING OF BRANCH CIRCUIT PROTECTION BY SELF-PROTECTED COMBINATION MOTOR CONTROLLERS 4. TEST METHOD FOR INSTANTANEOUS CIRCUIT BREAKERS USED FOR BRANCH CIRCUIT PROTECTION 5. GROUP INSTAL
3、LATION 6. GROUNDING TYPE ATTACHMENT PLUGS 7. KNOCKOUTS 8. SHORT CIRCUIT TESTING OF ALL DRIVES INCORPORATING SOLID STATE PROTECTION CIRCUITRY 9. BREAKDOWN OF COMPONENT TEST METHOD SETUP 10. COMBINATION DRIVE MOTOR CONTRUCTION 11. DYNAMIC BRAKES 12. COMMUNICATION CIRCUITS 13. MISCELLANEOUS REVISIONS 1
4、4. 2008 NEC PROPOSALS IMPACTING THE POWER CONVERSION INDUSTRY 15. UL/IEC 61800-5-1 HARMONIZATION 16. NEW STP INTEREST CATEGORIES 17. 90 C WIRE COMMENTS DUE: May 8, 2006 Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=Army Northwestern Div./7838506130 Not for Re
5、sale, 08/30/2006 05:07:36 MDTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION A meeting of the Standards Technical Panel of UL for Power Conversion Equipment was held on February 20 b)In which the only fuse enclosed
6、is a control-circuit fuse, when the fuse and control-circuit load other than a fi xed control-circuit load, such as a pilot lamp are within the same enclosure; or c)In which a means is provided for resetting all overload-protective devices from outside the enclosure, or kits are available to provide
7、 a means for resetting all overload-protective devices from outside the enclosure and a marking is provided in accordance with Instructions and Markings Pertaining to Accessories, Section 62; or d) The cover is interlocked such that the equipment is inoperable with the cover removed and the cover is
8、 marked as noted in 61.11. 61.11 Enclosures provided with removable covers, as noted in 6.4.2(d) shall be marked WARNING” and the following RISK OF SHOCK Disconnect Power Before Removing Cover. MARCH 24, 2006SUBJECT 508C-1- Copyright Underwriters Laboratories Inc. Provided by IHS under license with
9、ULLicensee=Army Northwestern Div./7838506130 Not for Resale, 08/30/2006 05:07:36 MDTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION 2. CONDUCTING SHORT CIRCUIT TESTING ON DRIVES WITH SOLID STATE DETECTION CIRCUITRY
10、WITH ONLY ONE TYPE OF BRANCH CIRCUIT PROTECTIVE DEVICE IN ORDER TO COVER ALL BCP DEVICES Discussion A proposal was submitted by: Jeffrey DesJarlais, Underwriters Laboratories Inc. The solid state short circuit detection circuitry provided in most power conversion equipment often acts to shut the dri
11、ve down, preventing the propagation of the short circuit current through the equipment, faster than the branch circuit protection device or devices installed in the test circuit, is able to function. This is supported by the requirements in paragraph 45.1.3 parts c), d), and e). Under these conditio
12、ns it should not be necessary to conduct the short circuit test twice, using both fuses and circuit breakers, as is required by paragraph 45.8.1. Where solid state short circuit detection circuitry is provided in accordance with 45.1.3 and it can be shown that the branch circuit protective device wa
13、s not subjected to an increase in current during the short circuit test, short circuit testing does not need to be conducted with both fuses and circuit breakers. The concept of the proposal was supported; however, it was suggested to revise the proposal to remove the text relating to exceeding 125%
14、 of the rated input current since it would be difficult to determine if this would be the correct percentage to use. Based upon the discussion, it was decided to revise proposed exception 2 to indicate that the short circuit detection circuitry should operate prior to the branch circuit protection o
15、perating. The proposals relating to this topic are being shown for informational purposes only and will be sent out for review and comment in a future CSDS work area. REVISED PROPOSALS 45.8.1 Drives shall always be tested with fuses (either semiconductor or non-semiconductor types) in accordance wit
16、h the UL 248 series of standards and circuit breakers (either inverse time or instantaneous trip types) in accordance with the Standard for Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures, UL 489. Exception No. 1: When the drive is marked to identify that branch ci
17、rcuit short circuit protection shall be provided by fuses only (either semiconductor or non-semiconductor types), then testing with circuit breakers is not required. Exception No. 2: When the equipment under test is provided with short circuit detection circuitry per 45.1.3 and it can be shown that
18、this circuitry operates prior to the branch circuit protection operating. 45.8.2 Testing with fuses (either semiconductor or non-semiconductor types) shall not be used in lieu of testing with circuit breakers (either inverse-time or instantaneous trip types). Exception No. 1: Testing with non-semico
19、nductor type fuses covers testing with inverse-time circuit breakers, when it is shown that the let-through energy (i2t) and peak let-through current (Ip) of the inverse-time current-limiting circuit breaker will be less than that of the non-semiconductor type fuses with which the drive has been tes
20、ted. Exception No. 2: When the equipment under test is provided with short circuit detection circuitry per 45.1.3 and it can be shown that this circuitry operates prior to the branch circuit protection operating. MARCH 24, 2006SUBJECT 508C-2- Copyright Underwriters Laboratories Inc. Provided by IHS
21、under license with ULLicensee=Army Northwestern Div./7838506130 Not for Resale, 08/30/2006 05:07:36 MDTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION 3. SIZING OF BRANCH CIRCUIT PROTECTION BY SELF-PROTECTED COMBINA
22、TION MOTOR CONTROLLERS Discussion A discussion item was submitted by: Jeffrey DesJarlais, Underwriters Laboratories Inc. UL 508C was recently revised to allow the use of Manual Self-Protected Combination Motor Controllers (MSPCMC), defi ned as Type E combination motor controllers in UL 508, as branc
23、h circuit protective devices. This is in line with Clause 430.52 (C)(6) of the NEC. However, requirements for sizing the MSPCMC devices were not included in the revisions to UL 508C. UL would like to discuss adding requirements that these types of devices be sized based on 100% of the power conversi
24、on input current as these types of devices can be easily mistaken for circuit breakers since their operation is similar. This could lead to misuse in the fi eld if the device were sized at 250% (or 400% in some cases) as is done for Listed circuit breakers. In addition, the specifi c MSPCMC part num
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