Westinghouse DB-50 Instructions Manual Download Page 26 | Manualshive

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Courtesy of NationalSwitchgear.com

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Summary of Contents for DB-50

Page 1: ...tions for Types DB 50 DBF 16 and DBL 50 Air Circuit Breakers Westinghouse Electric Corporation Switchgear Division East Pittsburgh Pa LB 33 850 3D Effective May 1970 Supersedes l ll 33 850 3 C March 1966 Courtesy of NationalSwitchgear com ...

Page 2: ...ation Operation Time Current Characteristics Adjustment of Calibration Settings Control Relay Shunt Trip Attachment Undervoltage Trip Attachment Undervoltage Time Delay Attachment Reverse Current Trip Attachment Field Discharge Switch Auxiliary Switch Alarm Switch Attachment Electric Lockout Attachment Key Lock Attachment Key Interlock Attachment Rectifier Unit for A c Undervoltage and A c Electri...

Page 3: ...ics of Special Series Overcurrent Tripping Device with Instantaneous Element Only 19 Schematic Diagram of Standard Series Overcurrent Tripping Device with Adjustable Long Delay and Adjustable Instantaneous Elements 20 Schematic Diagram of Selective Series Overcurrent Tripping Device with Adjustable Long Delay and Adjustable Short Delay Elements 22 Schematic Diagram of Series Overcurrent Tripping D...

Page 4: ... enclosure suitable to local operating conditions A selection of standard enclosures is available for various applications IMPORTANT To assure proper functioning inspect each breaker at regular intervals in ac cordance with a systematic maintenance schedule The frequency and character of the inspections will for the most part be deterinined by these verity of the duty performed The minimum re quir...

Page 5: ...a clockwise direction to move the contacts toward the closed position a Observe whether all parts are in proper alignment and move freely b Make certain that the studs have not been forced out of alignment c Be sure that the contacts are clean and properly aligned For a description of contact alignment refer to Contacts Page 9 3 If the contacts are in alignment and all parts move freely continue t...

Page 6: ...breaker resulting in possible excessive temperature rise Connecting cables or bus bars must be supported so that the circuit breaker studs will not be subjected to unnecessary stresses The circuit breaker studs and all con nections should be clean smooth and free from burrs to assure full contact area They should be firmly clamped or bolted in place to prevent excessive heating TABLE NO 2 Closing ...

Page 7: ...PA OLOCK AT TR1 ITTC i MANOL E 0 1 C ONLY FOR C LOSlNC ASSl lCIWH _ OCLOSE ih j I I I I l ll L_ i r l Ro F 0 Y I J I _ _ i 0 MOU mNG HC 5 j lrt RlPPP I 11 T ii I F f IZ E I I Q AC I PLK E I I I Ii I I J J i 1 1 J I i I IJ _ 31 IW I m I 1 I P CS T ON lt DICll TOR I i I m t ro I Ji 11 I j l 1 I I I J I 3 _T 1A t ff RO fAR TO tU Ml C IANl M It 9l_ l 0 eR AKE R R 1i I QC JJL 11L i 1 i IN TR P RE CONOt...

Page 8: ...OWING ATTACHMENTS CAN BE SUPPi JED Wl1HOUT INCREASING OVERALL DIMENSIONS 1 AUXILIARY SWITCHES 02 CIRCUIT MAX 2 SHUNT TRIP 3 UNDERVOLTAGE TRIP WITH OR W TflOUT TIM DELAY 4 ALARM SWITCH 5 ELECTRIC LOCKOUT 6 0PERATION COUNTER B 6FINGERS ff __ 12 OR 24 SECONDARY EL BASE SUPPLIED LOWER 12 CONTACTS CAN BE CAN BE OMITTED I tSECONDARY I CONTACTS UPPER l STUDS HANDLE I i 1 1 I 1 1 I SHUt T 11 l 31r 1 m INT...

Page 9: ...ng maintaining or adjusting contacts OPERATING MECHANISM The operating mechanism see Fig 3 is non adjustable and consists of a series of non ferrous links designed to secure low closing and tripping forces To check for friction raise the trip bar and slowly rotate the manual operating handle in close di rection The linkage should follow the handle without sticking A small quantity of lubricant is ...

Page 10: ...I I Page 10 l Courtesy of NationalSwitchgear com ...

Page 11: ...00 STATIONARY ARCING CONTACT 314 UPPER STUD 313 MAIN MOVING CONTACT 312 G 050 093 AUXILIARY 1J f I MAIN I CONTACT LOWER COIL TERMINAL 306 OVERGURRENT TRIPPING DEVICE 305 310 MOVING CONTACT HINGE 309 A LOWER STUD 307 UPPER COIL TERMINAL 308 _fl __ CLOSED TRIPPED OPEN RESET u Fig 3 Cross Sectional View of Type DB 50 Circuit Breaker Page lJ Courtesy of NationalSwitchgear com ...

Page 12: ...nto hole on right hand side of solenoid yoke 1 and allow moving core 3 to drop into brass tube 5 Pick up closing coil with brass tube and moving core and bring out through the U shaped foot on breaker Re assemble closing coil and details in reverse order from removal Take care to align stationary core 4 and moving core 3 in brass tube 5 OVERCURRENT TRIPPING DEVICE The overcurrent trip is an air de...

Page 13: ...ON CHEOO I tFRONT VIEW FACE f LATE HANO l a PANTOGRAPH uNKS INOT OWN I _ TEST POSITION MARK MANUAL TRIP PRESS LATCH TO REMOVE HANDLE Ai J Fig 3B Type DB 50 Three Posit1 on eff8rating Mechanism l 0 Courtesy of NationalSwitchgear com ...

Page 14: ... Care should be taken to make sure that bolts A B Fig 5 Series Overcurrent Tripping Device Showing the Assemhly of Calibration Case to Magnetic Circuit longer than specified above are not used because the ends of the bolts may bottom in coil terminal thereby causing a loose con nection OVERTRAVEL ADJUSTMENT CAUTION Do not attempt to check overtravel adjustment until the breaker has been completely...

Page 15: ...he breaker has been found add the standard overtravel which is one half turn of the trip screw downward Construction The overcurrent tripping device is air de layed with all of its elements completely adjustable A typical unit is shown ready for mounting on a circuit breaker pole unit in Figure 4 The tripping device consists oftwo main subassemblies namely 1 The magnetic frame and coil assembly as...

Page 16: ...standard device or another selective device of the same or of a dif ferent rating The calibration for the various elements are a Long delay pick up Adjustable with calibrated marks at 80 100 120 140 and 160 percent of coil rat ing b Long delay Adjustable with two calibrated marks at 30 and 20 seconds Calibrated marks at 20 and 12 seconds or at 60 and 40 seconds may be supplied for special applicat...

Page 17: ...i _ r __ 3 E CD Tota clearing time is the duration of 1 fault current flow including arcing 1 l l l 1 1 71f t r t i 1 1 r 1 2 time r f f j J t J flf li f 4 f j j H lf j j f t I Resettable delay curve shows the 1 a11 owoble du rot ion of current tlow l f East Jl E J ES f f i E t t t 1t r J1 for which the breaker will not trip 1 j J H t s If the overcurrent subsides within i 7 that time to BOo 0 or ...

Page 18: ...rks at 500 750 and 1000 1600 1600 1600 v I percent of trip unit roting gg gg r 1 Hl t H t n 11 n __ 600 600 600 vI 1 1 tt 1 r 500 500 500 H H short delay setting adjustable with 400 400 V 1 colibrated marks at 30 14 and 6 cycles I 350 r 1 30 20 10 7 6 4 2 I 9 t OOf S l 1 7 CD 6 1 Total cleoring time is the duration I I I 1 h 1 f f t t H ti 6 of fault current flow including arcing time ma imum Rese...

Page 19: ...00 h 1 14 rn GO l H cH H o oo 40 eo eo1oeo90 ill Hi CURRENT IN Xf 1J1ml S PERCENT OF COIL RA l fNG Fig 9 Tripping Characteristics of Special Series Overcurrent Tripping Device with Instantaneous Ele1nent Only Courtesy of NationalSwitchgear com ...

Page 20: ...hragm E The reset valve is shown as G Valve H is the long delay valve and it is permanently open to a calibrated setting This setting which controls the tripping time can be changed by means of dial S Figure 10 The magnitude of current at which the D A 4 T s G long delay will begin to operate is deter mined by the long delay pick up adjusting knob P Figure 10 The magnitude of current at which the ...

Page 21: ...g inside the moving core at the outset thereby subjecting the diaphragm to the constant force pattern of the spring Page 21 The tripping time will remain constant until interrupted by the instantaneous or short delay pick up wherever they occur For the same reason the tripping time in the short delay region remains constant with in creasing current for a given setting of the short delay Adjustment...

Page 22: ...rcurrent 1 ripping Device with Adjustable Long Delay and Short Delay Elements l l F E i p Fig 12 Schematic Diagram of Special Series Overcurrent Tripping Device with Instantaneous Element Only I p J H T s G t l I fi r I I i I Courtesy of NationalSwitchgear com ...

Page 23: ...or that purpose if a different setting is desired 4 Short Delay Pick Up The short delay pick up can be adjusted by means of knob Q Fig 11 The unit has been calibrated and the calibration plate marked at 500 750 and 1000 percent of the coil rating The pick up is usually placed on the 500 percent setting before shipment A different setting can be obtained by care fully turning the adjusting knob wit...

Page 24: ...ent setting before shipment A different setting can be obtained by carefully turning the adjusting knob with the help of a small screwdriver in the slots for that purpose CONTROL RELAY The control relay see Fig 15 mounts di rectly under the auxiliary switch It is a single coil mechanically tripped device with the coil suitable for continuous ener gization The operation sequence is out lined in Fig...

Page 25: ...Y MOLD STOP SUR FACE RELEASE LEVER COVER___ 159 MOVING CONT L P 153 R P 163 STATIONARY CONT L P 60 R P 165 CLOSING SOLENOID MOVING CORE OPERATING COIL 196 ADJUSTMENT RELEASE LEVER BLOWOUT COi L 161 ARC CHUTE FOR o c ONLY Fig 15 Control Relay Adjustment and Construction Details Courtesy of NationalSwitchgear com ...

Page 26: ...ve toward the closed position Trip breaker Reconnect closing coil leads to the con trol circuit wiring Check electric closing of breaker LOCATION SHUNT TRIP ATTACHMENT The shunt trip mounts on top of the platform immediately to the right of the operating mechanism See Fig 16 It is non adjustable and is intended for intermittent duty only The shunt trip cir cuit must always be opened by an auxiliar...

Page 27: ...ltage should have approximately 1 16 inch clearance to the trip bar when the breaker is half way closed UNDERVOLTAGE TIME DELAY ATTACHMENT The undervoltage air dashpot time delay attach ment mounts on the front of the undervoltage Page 27 trip replacing moving core cover See Fig 17 The needle valve screw in the top regulates the opening through which the air is forced and hence the time delay See ...

Page 28: ...ally after the circuit connections are complete as shown in Fig 2 Page 10 Maintenance Remove all power from the breaker and repeat the mechanical inspection given above Check for loose bolts and open cir cuit in potential coil FIELD DISCHARGE SWITCH The DBF 16 breaker is a two pole DB 50 breaker having special arc chutes and modi fied arcing contacts plus a field discharge switch mounted on the ce...

Page 29: ...NG Fig 18 Undervoltage Time Delay Attachment Construction Details TRIP CRANK ARMATURE COIL ASSEMBLY 10 FRONT YOKE a 0 sPR1Nol STUD I CALIBRATION I SPRING CAL BRAT ION I BACK THUMB NUT I I YOKE i L POTENTIAL COIL Fig 19 Reverse Current Trip Attachnient Construction Details Courtesy of NationalSwitchgear com ...

Page 30: ...the back cover shaft and end bushing Remove the rotor and change the contacts as desired Be sure to replace the shaft in the original position relative to one of the unchanged contacts Inspection Remove front cover and make sure con tacts are touching well before the end of travel Maintenance Check for loose bolts Replace contacts if necessary ALAHM SWITCH ATTACHMENT The alarm switch mounts above ...

Page 31: ...ARCING CONTACTS TOUCH ON CLOSING 1 BREAKER OPEN BREAKER CLOSED OPERATING ROD STOP SURFACE Fig 20 Field Discharge Switch Construction Details BACK COVER SHAFT 0 LEV ER CONTACT i i f ROTOR CASE FRONT COVER Fig 21 Auxiliary Switch Construction Details PagG 31 Courtesy of NationalSwitchgear com ...

Page 32: ...ey is then removable and the breaker is locked in the tripped position Replace key and rotate to the un locked position to free breaker trip button The key is also removable in this position Maintenance The device is non adjustable Check for loose bolts only KEY INTERLOCK ATTACHMENT FOR FIXED BREAKERS The key interlock mounts on the right side of the operating mechanism frame See Fig 24 When the k...

Page 33: ...kll ___J r s j _ _j_J I I TRAVEL h 2 GROUP I 13 12 t l f 1 11F _ IJic oJ I l 1 17 1 I iI T J 1i7 s rvP op s s Fig 23 Electric Lockout Attachment Construction Details Zf3 0 00 00 Courtesy of NationalSwitchgear com ...

Page 34: ... so that the common voltages for 60 cycles can be connected to the appropriate terminal on the unit A terminal block is mounted on the rectifier unit to facilitate all wiring NOTE For A C operated breakers with the clos ing rectifier mounted on the right side of the closing solenoid mechanism the rectifier unit required for A C electric lockout attachment must be mounted external lo the breaker In...

Page 35: ... A C _ Tl I L ___ Lt 1 fl I TRANSFORMER 11 iJ TERMINAL BLOCK RECTIFIER Page 3 5 TO A C VOLTAGE SOURCE SCHEMATIC Fig 25 Rectifier Unit for A C Electric Lockout Attachtnent Courtesy of NationalSwitchgear com ...

Page 36: ... A The breaker must be trip free when a 3 16 thick spacer is placed at the same point D Adjust trip screw C if necessary to secure this condition Fig 26 Type DBL Air Circuit Breaker DBL 50 BREAKER The DBL 50 breaker consists of a standard DB 50 breaker with special current limit ing trigger fuses mounted on the top studs Ref Fig 26 Courtesy of NationalSwitchgear com ...

Page 37: ...CIRCUIT DC NO 161 I I 2 MOVING CONTACT LEFT POLE NO 153 I 2 q MOVING CONTACT RIGHT POLE NO 163 I I 2 STATIONARY CONTACT LEFT POLE NO 160 I 2 q STATIONARY CONTACT RIGHT POLE NO 165 I I 2 COVER NO 159 I I POLE UNIT FIG 3 STATIONARY ARCING CONTACT NO 31q 3 3 6 12 STATIONARY MAIN CONTACT NO 313 3 I 3 MOVING ARCING CONTACT NO 301 3 3 6 12 MOVING MAIN CONTACT NO 312 6 2 I AUXILIARY MAIN CONTACT NO 310 1...

Page 38: ... 1 Page 38 Memorandum Courtesy of NationalSwitchgear com ...

Page 39: ... I Pago 39 Memorandum Courtesy of NationalSwitchgear com ...

Page 40: ...Printed in U S A Courtesy of NationalSwitchgear com ...

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