power distribution - Siemens

Lighting and Heating ContractorsMechanically and Magnetically Held Lighting ContactorsCLM 20 AmpCLM 100 AmpMechanically Latched Lightingand Heating ContactorThe CLM Lighting Contactors can beused with metal halide, mercury vapor,quartz halogen, tungsten and fluorescentlighting. They provide reliable andconvenient lighting control in numerousapplications, such as industrial plants,schools, hospitals, office buildings,shopping centers, airports, stadiums . . .literally everywhere lighting is required.The CLMs are listed under UL 508 withno derating when used open orenclosed. Combination lightingcontactors are listed for UL serviceentrance.UL listed File #E60310CSA Certified File LR 6535Type CLM 20 Amp LightingContactor Solid State ControlModulesThe CLM 20 amp lighting contactoris an electromagnetically operated,mechanically latched three wire controlcontactor. The most commonly usedmethod of control is a three positionmomentary contact switch with acenter-off position. The controllingdevice must be able to make the coilinrush current but need not break it.The coil current is interrupted by thecontrol contacts within the CLMcontactor. Power for the control line maycome from a separate source or directlyfrom the line side of the CLM contactor.The CLM contactor can also becontrolled by devices such as:▪ Break-glass control stations▪ Timers having single pole, doublethrow contacts▪ Photo-electric cells ▪ Energy management systems ▪ Microprocessors ▪ Occupancy sensors Control modules make it possible touse a controlling device that does nothave enough current-carrying capacityto control the CLM contactor directly.Control modules are also used whenthe control station is to be located ata distance greater than the allowablecontactor line run.Another use for control modules occurswhen the controlling device is onlyavailable as a single pole single-throwcontact necessitating a two wirecontrol line.Still another application for controlmodules is when start-stop threewire control is needed.Control modules also can make itpossible to operate the CLM coil fromits own incoming line at one voltagewhile providing the control at asecond, perhaps lower voltage.Two Wire Control Module(Accessory 47)The advantages of two wire controls are:1. Control station can have lowerampacity rating.2. Control station can be located anextended distance from the CLMcontactor.3. Control module can frequently becontrolled directly frommicroprocessor.4. Control devices can be two wiresingle pole, single-throw types.5. Control voltage may be different thanthe CLM coil circuit and at a lowervoltage level.Note: If the control power to the solidstate control module is lost while themodule is energized the lightingcontactor will open. If the line powerto the lighting contactor is lost while thecontactor is energized the contactor willnot change state with return of linevoltage. Power will be restored tothe load if the control module is stillenergized. Control station shouldbe the maintained type.Three Wire Control Module(Accessory 48)1. The accessory 48 consists of tworelays with contacts appropriatelyinterconnected which provides for aninterlocking that prevents both relaysfrom being energized simultaneously.2. This module has similar characteristicsto the two wire module (Accessory 47)except there is no change of switchcontact position upon loss of control linepower. Control stations should be themomentary type.SelectionStop-Start Control Module(Accessory 49)Stop-start three wire maintained controlis an arrangement used mostly whencontrolling motors, but can be used inlighting applications.Any number of momentary contactcontrol stations consisting of normallyopen start buttons and normally closedstop buttons can be used. Start buttonsare connected in parallel and stopbuttons in series.Operation (Magnetic Latch)A permanent magnet is built into thecontactor structure of the 30A, 60A,100A, and 200A contactors that willmaintain the contactor in its energizedstate indefinitely without using controlpower. When energized, a DC current isapplied that produces a magnetic fieldthat reinforces the polarity of thepermanent magnet, and the contactorpulls in immediately. The current to thecoil is disconnected by the coil clearinginterlock. In order to drop out thecontactor, it is necessary to apply a fieldthrough the OFF coil in the reversedirection to the permanent magnet.This momentarily cancels the magneticattraction and the contactor drops out.Coil and module failures are possiblewhen used with solid state relays andPLC outputs. 24-volt systems are ok touse, but 120 volts and above should bediscouraged. If higher values cannotbe avoided, an interposing relay shouldbe used.(Mechanically Latched)The 300 & 400A lighting and heatingcontactors operate using a latchingmechanism.Closing – When the “close” pushbuttonis operated, the closing coil is energized,closing the contactor. As the contactorcloses, the latch lever hooks over thelatch pin to mechanically latch thecontactor closed. The coil-clearingauxiliary contact de-energizes theclosing coil.Opening – When the “Trip” pushbuttonis operated, the trip solenoid coil isenergized, unhooking the latch leverfrom the latch pin, which allows thecontactor to open. As the contactoropens, the coil-clearing auxiliary contactde-energizes the trip solenoid coil.16 CONTROLPRODUCTSNEMA & GeneralPurpose Control Operation through control modules.Siemens Power Distribution & Control, SPEEDFAX 2007-2008 Product Catalog 16-71