power distribution - Siemens

Reduced Voltage Heavy Duty StartersFeatures and BenefitsSiemens manufactures the three commonlyused electromechanical reducedvoltage starters. Each one is designedfor specific application requirementsand consists of auto transformer,wye-delta and partwinding starters.The reduced voltage starter:▪ Reduces inrush current▪ Provides smoother acceleration of theload▪ Reduces starting torque▪ Reduces stresses on mechanicallinkagesGeneralCombination and non-combinationreduced voltage starter sizes rangefrom 0 to 6 including Siemens exclusivemotormatched half-sizes. Enclosuretypes include 1, 3R/12, 4 painted and4/4X stainless steel. All starters are ULlisted and CSA certified.Auto Transformer Starter▪ Maximum torque per amp▪ Three coil auto transformer for balancedstarting currents▪ 50, 65 and 80% voltage taps▪ Closed circuit transition▪ Adjustable starting time▪ ESP100 overload as standard▪ CPT supplied as standard▪ Wide range of factory modificationsWye-Delta Starter▪ Lowest starting torque▪ Closed or open circuit transition▪ Adjustable starting time▪ ESP100 overload as standard▪ CPT supplied as standard▪ Wide range of factory modificationsPart-Winding Starter▪ Simplest design – most economical▪ Adjustable starting time▪ ESP100 overload as standard▪ CPT supplied as standard▪ Wide range of factory modifications16 CONTROLPRODUCTSVarious Methods of Electro-Mechanical Reduced Voltage Motor Starting—A General ComparisonAutotransformer Part-Winding Wye-Delta50% 65% 80%Characteristic Tap Tap Tap 2 stepStarting current drawn fromline as % of that which would 25% 42% 64% 65% 33%be drawn upon full voltagestartingStarting current drawn by themotor50% 65% 80% 65% 58%Starting torque developed as25% 42% 64% 40% 33%% of that which would beIncreases slightlydeveloped on full voltagewith speedstartingSmoothness of acceleration First in order of Third in order of Second in order ofSmoothness Smoothness SmoothnessAllowable accelerating times 15 seconds at 200HP(typical) max. or 30 seconds on 5 seconds max. 5-60 seconds200HP based on Limited by motor Limited by motorNEMA medium duty design designtransformersStarting current and torque Adjustable within limitsand adjustmentsof various tapsFixedFixedNEMA & GeneralPurpose ControlSiemens Power Distribution & Control, SPEEDFAX 2007-2008 Product Catalog 16-63