1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES INC. CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared by UL LLC. It is normative for the applicable ULProduct Certification Program(
2、s); however, it is currently not part of the UL Standard(s) referencedbelow.Product Category (CCN): QYZSStandard Number: UL 218Standard Title: Standard for Fire Pump ControllersEdition Date: September 16, 2015Edition Number: 3Section / Paragraph Reference: Section 14.3.4Subject: Line Reactors Used w
3、ith Variable Frequency DrivesDECISION:14.3.4 A line reactor rated for continuous duty shall be provided. It shall be installed ahead of the VFDand shall have a 5 percent impedance rating as a minimum. A reactor provided as an integral part of aVFD may satisfy all or part of the 5 percent impedance i
4、f the reactor is connected on the line side of theconverter (rectifier) section of the VFD.Note 1: This is to reduce the likelihood of capacitor and rectifier damage and to avoid capacitor overvoltage shutdown of the VFDand to reduce the input current harmonics to near sinusoidal to avoid overheatin
5、g the VFD input circuit components and wiring. Thisreactor is required whether or not the controller or its VFD also contain a DC link reactor, choke (inductor), or swinging choke. Bybeing ahead of the VFD, it protects both the input rectifiers or SCRs, as well as reducing capacitor current (ripple
6、current) andcapacitor over-voltage (and over-voltage trip) in the energy storage capacitors. The line reactor enhances line quality by suppressingline transients and disturbances.Note 2: A DC link reactor or choke does not protect the input rectifiers or SCRs from line voltage transients.RATIONALE F
7、OR DECISION:Variable frequency drives (VFD) are often provided with line reactors as part of the factory assembledproduct. The requirement in paragraph 13.3.4 to install a line reactor ahead of the VFD having a 5 percentimpedance rating as a minimum will result in additional impedance for a VFD prov
8、ided with a reactor aspart of the factory assembled product. Most VFDs are designed to operate with a maximum line reactorimpedance. Excessive line reactor impedance may cause improper operation of a VFD such asoverheating. The revised requirement will permit a reactor provided as an integral part o
9、f a VFD to satisfyall or part of the 5 percent impedance requirement in 13.3.4 if the reactor is connected on the line side ofthe converter (rectifier) section of the VFD.Copyright 2018 UL LLCUL LLC, in performing its functions in accordance with its objectives, does not guarantee or warrant thecorr
10、ectness of Certification Requirement Decisions it may issue or that they will be recognized or adoptedby anyone. Certification Requirement Decisions are the opinion of UL LLC. in practically applying therequirements of the standard. They do not represent formal interpretations of the standard underA
11、merican National Standards Institute (ANSI) processes. UL LLC shall not be responsible to anyone forthe use of or reliance upon Certification Requirement Decisions by anyone. UL LLC shall not incur anyobligation or liability for damages, including consequential damages, arising out of or in connecti
12、on withthe use or reliance upon Certification Requirement Decisions. The electronic version of the CertificationRequirement Decision is the current version and previously printed copies may be outdated.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULThis document is published as a service to ULs certification customersSTANDARD NUMBER: UL 218 -2-
