26.3. Power Breakers, Contactors and Fuses. For Immediate Delivery or Tech Support call KMParts.com at (866) Contents.

Transcription

1 .3 Power Breakers, Contactors and Fuses Fuses General Contents Description Fuses General Product Overview Power Fuse Eaton s roots in the medium voltage power fuse business began over 75 years ago under Westinghouse Electric. In 1935, Westinghouse introduced the medium voltage boric acid expulsion fuse followed by the medium voltage current limiting fuse. Even today, medium voltage fuses continue to use that core technology. Eaton continues to build on the technology legacy by engineering higher performance, cost-effective power fuse products. Eaton s medium voltage fuses are manufactured and tested to the requirements of the C37-4X series of standards, which are maintained and updated regularly to maintain currency with industry practices. These standards are: IEEE Std. C37.40 IEEE Standard Service Conditions and Definitions for High Voltage Fuses, Distribution Enclosed Single- Pole Air Switches, Fuse Disconnecting Switches, and Accessories (ANSI). IEEE Std. C37.41 IEEE Standard Design Tests for High-Voltage (>1000V) Fuses, Fuse and Disconnecting Cutouts, Distribution Enclosed Single- Pole Air Switches, Fuse Disconnecting Switches, and Fuse Links and Accessories used with These Devices (ANSI). ANSI C37.42 IEEE Standard Specifications for High-Voltage (>1000V) Expulsion-Type Distribution- Class Fuses, Fuse and Disconnecting Cutouts, Fuse Disconnecting Switches, and Fuse Links, and Accessories used with These Devices (ANSI). ANSI C37.46 American National Standard for High Voltage Expulsion and Current Limiting Type Power Class Fuses and Fuse Disconnecting Switches. ANSI C37.47 American National Standard for High Voltage Current Limiting Type Distribution Class Fuses and Fuse Disconnecting Switches. The following IEEE standards are also applicable to the fuse products covered in this publication: IEEE Std. C37.48 IEEE Guide for the Application, Operation, and Maintenance of High Voltage Fuses, Distribution Enclosed Single-Pole Air Switches, Fuse Disconnecting Switches, and Accessories (ANSI). IEEE Std. C IEEE Guide for the Classification, Application, and Coordination of Current- Limiting Fuses with Rated Voltages 1 38 kv. A better understanding of some fuse terminology will help you understand and select the correct fuse. The following is a brief overview of those terms. Power vs. Distribution The differentiation is intended to indicate the test conditions and where fuses are normally applied on an electrical system, based on specific requirements for generating sources, substations and distribution lines. Each class has its own unique set of voltage, current and construction requirements (see C37.42,.46 and.47). Low vs. Medium vs. High Voltage While fuses are defined in the ANSI standards as either low or high voltage, Eaton has elected to name their fuses to correspond with the equipment in which they are installed. Therefore, per ANSI C84, our fuses are named as follows: Low voltage 1000V and below Medium voltage greater than 1000 to 69,000V High voltage greater than 69,000V V4-T-630 Volume 4 Circuit Protection CA E April For Immediate Delivery or Tech Support call KMParts.com at (866)

2 Power Breakers, Contactors and Fuses Fuses General.3 Expulsion vs. Current Limiting (Definitions per ANSI C ) An expulsion fuse is a vented Backup Fuses fuse in which the expulsion A fuse capable of interrupting effect of the gases produced all currents from the by internal arcing, either maximum rated interrupting alone or aided by other current down to the rated mechanisms, results in minimum interrupting current. current interruption. An expulsion fuse is not current limiting and as a result limits the duration of a fault on the electrical system, not the magnitude. A current limiting fuse is a fuse that, when its current responsive element is melted by a current within the fuse s specified current limiting range, abruptly introduces a high resistance to reduce current magnitude and duration, resulting in subsequent current interruption. Refer to Fuse Types Protection Range figure on Page V4-T-632 for a features comparison. Fuse Types There are three current limiting fuse types: Backup, General Purpose and Full Range. It is important that the user have an understanding of these definitions to ensure proper application of the fuse (see Fuse Types Protection Range figure on Page V4-T-632). Backup fuses are always used in a series with another interrupting device capable of interrupting currents below the fuse s minimum interrupting current. General Purpose Fuses A fuse capable of interrupting all currents from the rated interrupting current down to the current that causes melting of the fusible element in no less than one hour. General Purpose fuses are typically used to protect feeders and components such as transformers. Full Range Fuses A fuse capable of interrupting all currents from the rated interrupting current down to the minimum continuous current that causes melting of the fusible element, with the fuse applied at the maximum ambient temperature specified by the manufacturer. General Fuse Component Terms Fuse Refill Unit (of an Expulsion Fuse) A fuse refill unit is a replaceable assembly containing the calibrated current-responsive fuse element and certain other items that facilitate current interruption. On its own, the refill unit has no interrupting ability. A refill unit must be mounted in a fuseholder with a spring assembly to form a refillable fuse unit. The refill unit is the section of the fuse that must be replaced after a fuse operation. Fuseholder (of an Expulsion Fuse) A fuseholder is a reusable holder that when equipped with a fuse refill unit forms a fuse unit, capable of interrupting an overload or fault current. A fuseholder is supplied with a spring and shunt assembly, necessary to complete the internal interrupting assembly. The spring and shunt assembly is supplied with the fuseholder but is also available as a replacement part, as it may need replacement after several of heavy operations. Fuse Unit A fuse unit is a replaceable unit or assembly that is able, on its own, to perform current interruption. In the case of a refillable fuse unit, the refill unit must be replaced after a fuse operation. Where a complete fuse unit is supplied from the factory, the complete fuse unit must be replaced after a fuse operation. All currentlimiting fuses are fuse units. Exhaust Control Device When expulsion fuses are used in enclosures, exhaust control devices (filters, condensers or mufflers) are used to control the sound of the fuse operation, and to de-ionize and absorb the fuse exhaust products. These devices are normally supplied separately, because of different characteristics and ratings. They are reusable but may need replacement after several heavy operations. Mounting A mounting provides all the necessary parts to safely mount a fuse in its intended piece of equipment. The base is the metal support to which all other pieces attach. Insulators attach to the base and insulate the live fuse unit from the base and everything beyond the base. Live parts are the parts of the mounting that are energized once electricity is flowing. The live parts provide the means to hold the fuse unit in place, electrical contact, and a place to make line and load connections. Non-Disconnect Mounting A non-disconnect mounting does not provide a means for removing the fuse unit until the circuit is dead and the fuse unit can be removed manually. The fuse unit is held in place by friction through the use of fuse clips or by a cross bar. Volume 4 Circuit Protection CA E April V4-T-631 For Immediate Delivery or Tech Support call KMParts.com at (866)

3 .3 Power Breakers, Contactors and Fuses Fuses General Disconnect Mounting The disconnect mounting allows the fuse unit to be removed (off load) using an insulated hook stick. The hookstick grabs a pull ring and disconnects the fuse unit, which may then be lifted out of its mounting. Dropout Mounting Dropout mountings are used in outdoor applications. The fuse unit is equipped with a mechanical trigger that unlatches the upper contact, allowing the fuse unit to drop out, increasing the dielectric separation, and providing visible indication of a blown fuse. Live Parts Live parts were briefly discussed as part of the Mounting definition. Everything above the insulators on the mounting excluding the fuse unit, fuse holder, and the fuse end fittings (if required) are considered the live parts. Fuse end fittings are discussed next and are not required with non-disconnect live parts, but are required and included with disconnect live parts. Live parts may be sold separately as replacement parts or for new OEM applications. End Fittings End fittings are metal parts that attach to each end of a fuse unit s ferrules (end caps). As previously mentioned, they are used solely with disconnect fuse applications or when converting a nondisconnect to a disconnect fuse configuration. When end fittings are ordered, a fitting for each end of the fuse is included. Keep in mind that end fittings can become damaged in use and, therefore, are sold separately from the live parts when necessary. It is not necessary to purchase an entire set of live parts when only the end fittings are required. General High Voltage Fuse Comparison Expulsion Vented Electromechanical Interrupts at current zero Generally higher voltage and current application capabilities Different time/current characteristics Fuse Types Protection Range Current Limiting Type Interrupting Current Current Limiting Sealed Static Limits fault current Generally higher interrupting ratings Different time/current characteristics BACKUP GENERAL PURPOSE FULLL RANGE i i hr. i min. i max. V4-T-632 Volume 4 Circuit Protection CA E April For Immediate Delivery or Tech Support call KMParts.com at (866)

4 A ability, 2 able, 2 above, 3 abruptly, 2 absorb, 2 Accessories, 1 acid, 1 after, 2 ago, 1 aided, 2 Air, 1 All, 2 all, 2 allowing, 3 allows, 3 alone, 2 also, 1-2 always, 2 ambient, 2 American, 1 An, 2 an, 1-3 and, 1-3 another, 2 ANSI, 1-2 applicable, 1 Application, 1 application, 2-3 applications, 3 applied, 1-2 April, 1-3 arcing, 2 are, 1-3 As, 3 as, 1-3 assembly, 2 at, 1-3 attach, 2-3 available, 2 B BACKUP, 3 Backup, 2 bar, 2 base, 2 based, 1 be, 2-3 because, 2 become, 3 began, 1 below, 1-2 better, 1 beyond, 2 blown, 3 boric, 1 Breakers, 1-3 brief, 1 briefly, 3 build, 1

5 business, 1 but, 2-3 by, 1-2 C CA, 1-3 calibrated, 2 call, 1-3 can, 2-3 capabilitieslifted, 3 capable, 2 caps, 3 case, 2 causes, 2 certain, 2 characteristics, 2-3 Circuit, 1-3 circuit, 2 Class, 1 class, 1 Classification, 1 clips, 2 com, 1-3 comparison, 2 ComparisonThe, 3 complete, 2 Component, 2 components, 2 condensers, 2 Conditions, 1 conditions, 1 configuration, 3 connections, 2 considered, 3 construction, 1 contact, 2-3 Contactors, 1-3 containing, 2 Contents, 1 continue, 1 continues, 1 continuous, 2 Control, 2 control, 2 converting, 3 Coordination, 1 core, 1 correct, 1 correspond, 1 cost, 1 covered, 1 cross, 2 currency, 1 Current, 1-3 current, 1-3 Currentfittings, 3 currents, 2 Cutouts, 1 D damaged, 3 de, 2 dead, 2 defined, 1 definition, 3 Definitions, 1-2 definitions, 2 Delivery, 1-3 Description, 1 Design, 1 Device, 2 device, 2 Devices, 1 devices, 2 dielectric, 3 Different, 3 different, 2 differentiation, 1 Disconnect, 2-3 disconnect, 2-3 Disconnecting, 1 disconnects, 3 discussed, 3 Distribution, 1 distribution, 1 does, 2 down, 2 drop, 3 Dropout, 3 duration, 2

6 E Each, 1 each, 3 Eaton, 1 eaton, 1-3 effect, 2 effective, 1 either, 1-2 elected, 1 Electric, 1 electrical, 1-2 electricity, 2 Electromechanical, 3 element, 2 Enclosed, 1 enclosures, 2 End, 3 end, 3 energized, 2 ensure, 2 entire, 3 equipment, 1-2 equipped, 2-3 Even, 1 Everything, 3 everything, 2 excluding, 3 Exhaust, 2 exhaust, 2 Expulsion, 1-3 expulsion, 1-2 F facilitate, 2 factory, 2 fault, 2-3 features, 2 feeders, 2 ferrules, 3 figure, 2 filters, 2 fitting, 3 Fittings, 3 fittings, 3 flowing, 2 followed, 1 following, 1 follows, 1 For, 1-3 for, 1-3 form, 2 forms, 2 friction, 2 from, 2-3 FULL, 3 Full, 2 Fuse, 1-3 fuse, 1-3 Fuseholder, 2 fuseholder, 2 Fuses, 1-3 fuses, 1-2 fusible, 2 G gases, 2 GENERAL, 3 General, 1-3 Generally, 3 generating, 1 grabs, 3 greater, 1 Guide, 1 H has, 1-2 have, 2 heavy, 2 held, 2 help, 1 High, 1, 3 high, 1-2 higher, 1, 3 hold, 2 holder, 2-3 hook, 3

7 hookstick, 3 hour, 2 hr, 3 I IEEE, 1 if, 3 Immediate, 1-3 important, 2 In, 1-2 in, 1-3 included, 3 increasing, 3 indicate, 1 indication, 3 industry, 1 installed, 1 insulate, 2 insulated, 3 Insulators, 2 insulators, 3 intended, 1-2 internal, 2 Interrupting, 3 interrupting, 2-3 interruption, 2 Interrupts, 3 introduced, 1 introduces, 2 ionize, 2 is, 1-3 It, 2-3 it, 2 items, 2 its, 1-3 K Keep, 3 KMParts, 1-3 kv, 1 L legacy, 1 less, 2 Limiting, 1-3 limiting, 1-2 Limits, 3 limits, 2 line, 2 lines, 1 Links, 1 Live, 2-3 live, 2-3 load, 2-3 Low, 1 low, 1 M magnitude, 2 maintain, 1 maintained, 1 Maintenance, 1 make, 2 manually, 2 manufactured, 1 manufacturer, 2 max, 3 maximum, 2 may, 2-3 means, 2 mechanical, 3 mechanisms, 2 Medium, 1 medium, 1 melted, 2 melting, 2 mentioned, 3 metal, 2-3 min, 3 mind, 3 minimum, 2 mount, 2 mounted, 2 Mounting, 2-3 mounting, 2-3

8 mountings, 3 mufflers, 2 must, 2 N name, 1 named, 1 National, 1 necessary, 2-3 need, 2 new, 3 next, 3 no, 2 Non, 2 non, 2-3 normally, 1-2 not, 2-3 O OEM, 3 of, 1-3 off, 3 On, 2 on, 1-3 once, 2 one, 2 only, 3 Operation, 1 operation, 2 operations, 2 or, 1-3 ordered, 3 other, 2 our, 1 out, 3 outdoor, 3 over, 1 overload, 2 Overview, 1 overview, 1 own, 1-2 P Page, 2 part, 2-3 Parts, 3 parts, 2-3 per, 1-2 perform, 2 performance, 1 piece, 2 pieces, 2 place, 2 Pole, 1 Power, 1-3 power, 1 practices, 1 previously, 3 produced, 2 Product, 1 products, 1-2 proper, 2 protect, 2 Protection, 1-3 provide, 2 provides, 2 providing, 3 publication, 1 pull, 3 purchase, 3 Purpose, 2 PURPOSELive, 3 R RANGE, 3 Range, 2 range, 2 Rangeused, 3 Rated, 1 rated, 2 ratings, 2 ratingsunit, 3 reduce, 2 Refer, 2 Refill, 2 refill, 2

9 refillable, 2 regularly, 1 removed, 2-3 removing, 2 replaceable, 2 replaced, 2 replacement, 2-3 required, 3 requirements, 1 resistance, 2 responsive, 2 result, 2 resulting, 2 results, 2 reusable, 2 ring, 3 roots, 1 S safely, 2 Sealed, 3 section, 2 see, 1-2 select, 1 separately, 2-3 separation, 3 series, 1-2 Service, 1 set, 1, 3 several, 2 shunt, 2 Single, 1 sold, 3 solely, 3 some, 1 sound, 2 sources, 1 specific, 1 Specifications, 1 specified, 2 spring, 2 Standard, 1 standards, 1 Static, 3 Std, 1 stick, 3 subsequent, 2 substations, 1 such, 2 supplied, 2 Support, 1-3 support, 2 Switches, 1 system, 1-2 T Tech, 1-3 technology, 1 temperature, 2 terminology, 1 Terms, 2 terms, 1 test, 1 tested, 1 Tests, 1 than, 1-2 that, 1-3 The, 1-3 the, 1-3 their, 1 then, 3 There, 2 Therefore, 1 therefore, 3 These, 1-2 these, 2 They, 2 they, 1, 3 this, 1 those, 1 three, 2 through, 2 time, 3 to, 1-3 today, 1 transformers, 2 trigger, 3 Type, 1, 3 Types, 2-3 types, 2 typically, 2

10 U under, 1 understand, 1 understanding, 1-2 unique, 1 Unit, 2 unit, 2-3 units, 2 unlatches, 3 until, 2 updated, 1 upper, 3 use, 1-3 used, 1-3 user, 2 using, 3 with, 1-3 within, 2 www, 1-3 Y years, 1 you, 1 Z zero, 3 V Vented, 3 vented, 2 visible, 3 Voltage, 1, 3 voltage, 1, 3 Voltageengineering, 1 Voltages, 1 Volume, 1-3 vs, 1-2 W were, 3 Westinghouse, 1 When, 2-3 when, 2-3 Where, 2 where, 1 which, 1-3 While, 1 will, 1