Low-Voltage Motor Control Center
16Pages

MOTOR CONTROL CENTERS

Allis Electrics MCC Type A-S. A-D, arc providing highly eftiLienl service in large-scale power, metal and petroleum plants and in numerous, general utdusirul applications as an integrat- ed puncl primarily for eon I ml nf low-village motors upto66<)V 5(l/60Hz 1. Personnel safely and ease of maintenance. 1 Tlk' slniiK -IniL-nirc resets shotk Arid vibration, 3. tlaiy mounting of channel base& and intereonnecUon of enelosirtW- 4, Easy access to uml wrapper when replacing wiring and parts. 5. Easy connection of cables and control wires ilvm ou^ulc to unit step teiTninatorv o. I he unit wrappwr...

|f'i I >i si -, ITII ii.Lfnn ruin^VnibLLj hiriy^n JLru pruviiUzd un J LI uinl compartmenLs^kn vertical wire- Ways.. Cop htjrimmttl wirewnyn ;iml boimm hori/flnlJLl wire UMVI 11. Overload relay can operate nn each urn dc^ir hy insulated push button withnur opening the 12. Stabs are mounted in a glass reinforced plastic insulation block which total k shrtnids each stab and absolutely ensure positive alignment of the slabs with vertical bus. 1.1.Illation of the vertical bus compartuienl from tlte unit cortiparimcTits is uwumplishcd by a full heielit barrier which is molded elass reinforced...

Structure shall be totally enclosed tree-standing assemblies 2350mm high, MUmm wide 550rnni Jeep tor front mounted only, tind 60Umm deep lor buck to back mounted structures. The slruclure 1'ruiiiework is made of 2,3mm formed steel chnnnels. The sub-Frames fur the front und rear of euch structure an: welded. These su h-ft amcs are then bollfid to longitudinal members to Form the complete tramc which is rigid and self-supporting. Side, back mid roof sheets are mounted xvitb screw fasteners for quick and easy removal when desired. Doors mounted on removable pin hinges are provided on all unit...

The fmishtfilouriii standard colour 5V 7/1 (light gray). The unil pun the top harrier of each unit .space. ETI conjunction with the unit wrapper this provides isolnlion between aJjuic^nL Hfrtlj and wireways. It also provided the Jock and losL [jowLion with lock which. & located on the unit wrapper. Ftt-4 REAK VIEW Of N&UCrVRE FRAMEWORK fV/j SMEWEW tWJT PAN Fig_7 CONNECTION OFSVBFttAME ASD MAIN FRAMEWORK

VERTICAL WIREWAY A verlicul wirowlj" is provided in each vertical structure. Located on the richi side;., it extendi over lhe- full height of the structure. Sup[H>it& arc provided at .suitable intervals to iecure all vyiring and cables. The wireway npening is covered by rwti doors* top and bot- tom. The doors open opposite to Ihe unit doom for maximum accessibility. The doors are mounted on removable pin hinges Tor quick detachment and are .secured in the closed position by two fasteners. HORIZONTAL WIREWAY Fif,S VERTICAL WI/ttWAV the hdiLuin horizontal wircway is 300mm or 200mm high as...

Hoii/onial i h ree-p hasc bi i s-h^ir.^ extend throtieli [he enclosures located in the top or hoiiom, They provide ihree-phase power Jivtnbutton from Ltic- incoming line or primary disconneci device to each vertical structure in an assembly. The bus har.s arc mounted in a vertical plane, edge to edge. This mounling produces an exceptionally strong asscemhly able to withstand high fault cur- renl stresses. Standard horizontal bus Inaciiij; is WKA RMS symmetrical amperes. Dus braces arc molded from a glass reinforced polyester material wiih high strength which Is uon-iracking and impervi- ous...

Ground bus is available in, 5l x 3fJW (in mm) cnppcr. Mounting is atniss rhc kttKirn uf each vertical structure in tlic horizontal wiitway. TEic lius Lan n\so be mounted jucmssihc n>p,

CONTROL & LOAD TERMINATIONS Far Type A wiring, each unit is ji^cmblcd and devices intcrwed. Terminal blocks are not supplied ami cunirol and wiring is internal to the urrit- Fur Type Q wiring, control wires arelcrminatctl at blocks within the mm. Refer m ihc discus- sion of units far types of icrminjd blocks sivniljtble, For Type C wiring, control and Load wires arc extended from the unit terminal bleaks m man tcr terminal block* located at the tnp or bottom nf any vertical structure. Masier Ltrminal blocki are fjneU at lbe horizontal wire way al the top or at the bottom. INCOMING LINE...

UNIT CONSTRUCTION Eftctl unit is designed inlu basic modular heights wiili die smallest unii ^flGmm lu'gh in All units of the same height are inter- UNIT DOOR Each unit compartment skill W provided with an individual t'ronl dewr Unil doors tux [tinned of 2.t) or 1.6 mm steel with a 2t) mm width flange on all four .sides. The flange adds, rigidity lo the door and piovidcs R stir- fate to coiitLtin dwr gaaketiug when uppliL'd The doors will open opposite to wire way doors permitting optimum access in the unit compartment. The doors, arc mow cited on removable pin hinges. This, permit ijuick...

UNIT WRAPPER The LLFIIL wrapper is lubrieuL- ed of LGmiu steeL After fabrica- tion, it is cleaned bind given a rust inhibiting phosphatizing treatment. The unit wrapper pro- vides three iides. of a rujaged s-teel shell anil lhe mountirij base The smallest unit measures, 270nir[i high, a maximum height The unil wrapper is desired [<i prmide simple Spuec fur uable entry Furtrtl the wireway The unil wrapper han a mini mum of fuur mcjunliny points, Lwd (in euuh .fide, whieh support Lhc linil in lhe HlrLicture. They engage: guide rails located ncsr lhc top of each unit space. Thisi mourning pyim...

OTHER PARTS STAB ASSEMBLY Two component copper alloy stab incor- porates ihc ultimate in mechanical simplicity to provide precise control of contact pressure on the bus. This, assures a positive connection permits easy unit insertion and withdrawal. SeJi" aligning stabs are mounted in a glass reinforced plastic insulation block which totally shrouds each stab and absolutely ensure?, positive alignment of the stabs with the vertical bus. The insulation block is also an integral pari of the phaf,u tu phuve isolation GUIDE RAIL The guide rails provide preuixe align- niLinl nf the unil Slafe*...