Synchronous Motors - Электродвигатели

Cooling and ProtectionThe three most commonly used cooling arrangements areopen air, air-to-water and air-to-air cooling.10An open air cooled motor (IC0A1)with drip proof protection (IP23)A totally enclosed motor (IP54) using anair-to-water heat exchanger (IC8A1W7)Open Air CoolingAir-to-water Closed Circuit CoolingOpen air cooling can be used wherethe air in the immediate environment isrelatively clean and there is adequate aircirculation. The cooling air is typically drawnin through air filters, passed through the activeparts of the motor, and then exhausted backto the environment. If the room ventilationsystem cannot compensate for the temperaturegradient, the motor air outlet can also beducted to allow the air to be exhaustedoutdoors.The cooling air circulates in a closed circuitthrough the active parts of the motor and thenthrough an air-to-water heat exchanger.This configuration passes hardly any heat to thesurrounding environment, and represents anideal solution for situations where closed circuitcooling is required due to installation outdoors,installation in a hazardous area, or whenever thequality of the surrounding air is not otherwisesuitable for direct cooling. It is also ideal forinstallations in machine rooms with limitedventilation, such as on board ships or inpumping stations which are fully enclosed.ABB / AMZ Synchronous Motors EN 08-2005

ProtectionThe enclosures feature protection in classesIP23, IP44, IP54 and IP55 (totally enclosed),or equivalent NEMA protection classes.Motors are also available for hazardous areasin accordance with IEC/ATEX or NECdefinitions (non-sparking or pressurizedconstruction).A totally enclosed motor (IP54) using anair-to-air heat exchanger (IC6A1A6)Air-to-air Closed Circuit CoolingThe cooling air circulates in a closed circuitthrough the active parts of the motor andthrough an air-to-air heat exchanger.This solution is generally used in situationswhere a closed circuit cooling system – such asair-to-water cooling – is required but water isnot readily available. This cooling arrangementrequires an additional shaft mounted or separateelectric fan to ensure sufficient air flowthrough the cooler.ABB / AMZ Synchronous Motors EN 08-200511

Windings and StatorForm wound coils are usedfor medium or high voltagestators. High voltage coilsinclude a semiconducting layerto decrease the electrical fieldat the slot surface.Stator Winding and Insulation ClassesRotor and Exciter WindingsMedium and high voltage windings up to15 000 V are made of form wound rectangularcopper wire insulated with multiple layers ofglass-fiber reinforced mica-tape. Additionalvoltage stresses associated with convertersupply are allowed for.Rotor and exciter windings are made to matchthe insulation class of the stator. This ensureshigh reliability and a long service life even withasymmetric loads and exceptional conditions.All materials used, including the vacuumpressure impregnation resin, exceed thermalclass F (155 C) requirements.After insertion into the corresponding slots,the coils are firmly held in place by means ofsoft wedges and surge ropes at the coil headsprior to vacuum pressure impregnation.The completed process assures long andtrouble-free service.12The rotor windings are either made of preformed enameled rectangular copper wire orflat copper. Proper supports between adjacentwindings are used to ensure stability up tothe rated overspeed. The rotors are typicallyvacuum pressure impregnated as a whole unit.Exciter windings are made of enameled copperwire. Proper glass fiber supports are used inthe exciter rotor to ensure stability up tothe rated overspeed. The exciters are alsovacuum pressure impregnated.ABB / AMZ Synchronous Motors EN 08-2005

The automated manufacturingprocess is located in anenvironmentally controlled area,ensuring that each medium orhigh voltage coil is producedwith uniform and consistentquality for the highest reliability.StatorThe stator frame is a rigid steel structurethat has been designed to withstand vibrationsinduced by the driven equipment.Frames up to size 1120 are of modular type.The stator core is welded into a cylinder, afterwhich the end-modules with feet are welded tothe stator core. The bearings are flange-mountedon the end-shields. For larger motors integratedpedestal frames incorporating both the statorcore housing and feet are typically used.ABB / AMZ Synchronous Motors EN 08-2005The bearings are mounted on pedestals integratedwith the frame, allowing transportation andinstallation of the motor as a fully assembledsingle unit. In applications with high axial thrustforces, like rolling mills, separate pedestalbearings are used.The stator core itself is built of stacked, highgrade, low-loss laminated electric sheet steel,insulated on both sides with a heat-resistantinorganic coating. Radial cooling ducts ensureuniform and effective cooling of the stator.13

InsulationMCI Insulation SystemABB uses the MICADUR Compact Industry(MCI) insulation system, which is based on thevacuum pressure impregnation (VPI) method.The VPI and curing of the completely woundand connected stator winding with a speciallyformulated epoxy resin ensures a sealed andhomogenous insulation system. This results inhigh dielectric strength, excellent heat transfer,and the elimination of hazardous internalpartial discharges.ABB has been using the MCI system for30 years. In that time it has been used on tensof thousands of our larger motors and generators,which are operating successfully all over theworld. No primary insulation failures due tothermal ageing have been experienced. Thermallifetime tests performed on the MCI system alsoshow that its endurance substantially exceedsIEC and IEEE requirements.MCI insulated windings require very littlemaintenance. Usually it is sufficient to ensurethat the cooling ability of the winding is notreduced by the ingress of moisture or dirt duringperiods when the motor is not operating.14ABB / AMZ Synchronous Motors EN 08-2005

The VPI process features: High vacuum cycle – removing air andmoisture from the voids and pores of theinsulation. Highly stable epoxy resin – ensuringsuperior protection under the most difficultenvironmental conditions (against lubricants,oil, moisture, common solvents, chemicallyaggressive gases, abrasive dust, tropicalclimate etc.). High pressure cycle – forcing the resin intoeven the smallest pores. Oven curing – after the VPI process hasbeen completed, stators and rotors are curedin an oven at high temperature. This producesvery strong and stable insulation, exhibitinghigh mechanical and electrical strength.This is especially important in order to resistinadvertent high stresses from out-of-phasesynchronization, transients and short circuits.Even the largest wound stators are impregnatedas complete units. This ensures that both theinsulation and the mechanical properties of thewindings are excellent – which means thatthey can withstand prime mover inducedvibrations and the mechanical stresses causedby transients such as short circuits.ABB / AMZ Synchronous Motors EN 08-200515

RotorThe characteristics of the rotor play a crucial part in achievingthe best possible levels of electrical and mechanical performance.As a result, ABB continues its development work to optimizerotor designs.State of the art precisionmachined forgings are usedin rotors with maximumreliability.ShaftThe rotor comprises a shaft, a rotor centerfor larger machines, and salient poles. The shaftis manufactured of forged or rolled steel andmachined to exact specifications. Rotors forframe sizes 1250 and greater are normallyequipped with a separate rotor center which isshrink-fitted onto the shaft. The shaft ends arenormally cylindrical or flanged.PolesWound rotor poles are normally manufacturedfrom 2 mm laminated steel sheet. The sheets arepressed together with inserted steel bars whichare welded to the end plates. The pole structureis integrated or the poles are secured to the shaft16ABB / AMZ Synchronous Motors EN 08-2005

The robust constructionof permanent magnet rotorsoffers maximum reliability forvariable speed applications.or rotor center by bolts from above or below, orby means of dovetails. The poles are often fittedwith a copper or brass damper winding.Wound rotor assemblies are vacuum pressureimpregnated (VPI) for excellent insulation andmechanical strength. After impregnation, thebalance of the complete rotor assembly isdynamically checked.Permanent magnet poles are used in certainvariable speed applications. Permanent magnetrotors do not require any excitation system, andare simple, low weight and robust constructionswith virtually no maintenance requirements.High pole numbers can be used when necessaryin slow speed applications.ABB / AMZ Synchronous Motors EN 08-200517

Excitation SystemsFixed speed synchronous motorstypically have a brushless exciter and anautomatic voltage regulator. The brushlesssystem has no wearing parts, and theexternal excitation power requirementis small.Variable speed synchronous motorsrequiring very fast speed or torque controlare generally equipped with brushes and aslip ring unit for excitation and control of themotor from the converter. For dynamicallyless demanding applications the brushlesssystem is optimal.Variable speed synchronous motors basedon permanent magnet rotors do not requireany excitation system.Brushless Excitation SystemThe brushless exciter is a separate AC generatormounted on the motor shaft. The exciter islocated at the non-drive end. In fixed speedmotors the field winding is DC fed; in variablespeed motors (and fixed speed motors with LCIstarting) the field winding is AC fed. The exciteris vacuum pressure impregnated using the MCImethod, ensuring that the windings are sealedand secured.In fixed speed motors the excitation currentcontrol and related protections are based ona separate excitation control system. This utilizesthe UNITROL 1000 digital voltage regulator,which features both automatic and manualoperating modes. The automatic mode maintainseither the power factor or reactive power atset values regardless of the active power.Manual control allows a constant excitationcurrent to be maintained. Using the regulatorit is possible to change parameters, settings18and operating modes during running.The regulator set points can be changed locallyor remotely using an increase/decrease switch.The system also includes the necessaryprotections. Typical features are: Excitation field application logic Out of step / pull out protection Minimum and maximum field protection Stall / Too long start protection (based onspeed of motor) Rotating diode monitoring. Measures ripplecomponent of DC excitation current andprotects against diode short circuit and cut-off Meters for power factor and excitation current All necessary push buttons (Lamp Test,Trip Reset), control switches (Auto/Manual,PF/VAR, Increase/Decrease) and indicatorlamps (Ready For Start, Excitation ON,Excitation Trip, Diode Fault, Out Of StepTrip, Incomplete Start) Excitation transformer installed inexcitation cubicleABB / AMZ Synchronous Motors EN 08-2005

Windows-based commissioning, maintenanceand communication software Potential free (dry) contacts for communicationwith plant control system (Ready For Start,Excitation ON, Excitation Trip, Diode Fault,Out Of Step Trip, Incomplete Start) 4 –20 mA signals from measured values(PF, MVAr) to plant control system.Optional features, including a communicationport and motor protection relays, are availableon request.In variable speed motors with a brushlessexcitation system, the converter provides thesupply voltage and excitation control, as wellas the necessary protections, instead of aseparate excitation control system.ABB / AMZ Synchronous Motors EN 08-2005Static Excitation SystemExcitation with slip rings and brushes istypically used with variable speed motors, withthe supply voltage and excitation control, aswell as the necessary protections, providedby the converter.To supply the excitation current into the rotor,slip rings are installed on the motor shaft withaccess via removable inspection covers. The sliprings, together with the mounting flange or hub,are usually made of steel and are normallymounted as a single unit. Slip ring units withbrass rings, as well as split flange mounted units,are available on request. The slip ring unit isequipped with brass connection pins tofacilitate installation.19

BearingsThe choice of bearing arrangement and typeis based on the application, radial and axial loads,rotation speed, coupling type, customerpreferences. Operating conditions such asambient temperature, air cleanliness, vibrationsand shocks affecting the bearing are also takeninto account.The life expectancy of sleeve bearings isvery long provided that the operating conditionsand maintenance intervals are as specified.To prevent bearing damage from circulatingcurrents, all non-drive end bearing housings areelectrically insulated by means of non-conductingfilm. In VSD motors the drive end bearing is alsoelectrically insulated and the shaft is groundedby an earthing brush.Sleeve bearings withstand high levels ofvibration and they offer excellent quality andperformance, as well as first-class reliability.The bearing assembly is highly suitable forstatic as well as radial and axial dynamic loads.Excellent heat transfer capability makes thesebearings especially suitable for high speedapplications. The bearings are of the splittype and easy to maintain.The bearings are typically self-lubricated bymeans of an oil ring. The lubricating oil is pickedup by the oil ring and transferred directly to theshaft.In the case of high loads, high speeds, highambient temperature or inclined operatingAccessoriesWe offer a large selection of accessories to meetour customers’ requirements. Certain accessoriesare included as standard, depending on the sizeand type of motor. For non-listed accessories,please contact us.Excitation Digital voltage regulators Free standing cubicle with chosenprotection equipmentTerminalsMeasuring and Monitoring Separate air insulated terminal boxes Pt-100 resistance temperature detectors Separate phase insulated terminal boxesin stator winding Pt-100 resistance temperature detectorsin bearings Pt-100 resistance temperature detectorsfor hot or cooled air Leakage detectors for water cooled motors Separate phase segregated terminal boxes Auxiliary terminal boxes Termination kits for phase segregatedterminal boxes Cable glands (e.g. Roxtec) Speed and position encodersShaft End Alternatives Thermometers for cooling circuit or bearings Cylindricalfor local or remote monitoring Vibration probes for sleeve bearingsProtection Flanged Conical Two shaft ends Air filters at air inletLubrication Anti-condensation heaters Hydrostatic jacking Bearing insulation External lubrication unit Differential protection current transformers Earth fault protectionCooling Surge arrestors CuNi or stainless steel, single or double tube, Surge capacitorsfresh or sea water heat exchangers for air-to- Diode failure monitoring unitwater closed circuit cooling Ex accessories for hazardous areas20ABB / AMZ Synchronous Motors EN 08-2005

Flange mounted sleeve bearingposition, an external cooling and circulation circuitfor the oil may be necessary, unless the oil comes directfrom the driven equipment lubrication oil system.In certain applications a jack-up system may be necessaryfor starting with slow speed running.Flange mounted sleeve bearings are typically usedfor frame sizes 0710-1120 and they are mounted onthe end-shields of the motor.Pedestal mounted sleeve bearingPedestal mounted sleeve bearings are typically usedfor frame sizes 1250-2500. Motors with integral pedestalbearings are as easy to mount and align as motors withflange mounted bearings. The motors are normallydelivered ready assembled and require no furtherassembly on site. Separate pedestal bearing motorsare often mounted on a common base frame. Aluminum or stainless steel air-to-air heatexchangers with shaft mounted secondary fans orelectric fans for air-to-air closed circuit coolingHazardous Area Modifications Overall design for EEx nA/Ex n; EEx p/Ex p(all ATEX certified), or CI1 Div2 requirements Purging and pressurization systemsTerminal BoxesSeparate main terminal box is mounted on the sideof the motor, featuring bus bars outside the motor frameand allowing connections from any specified direction.Neutral terminal box is typically mounted on the oppositeside of the motor from the main terminal box. Forauxiliary and instrument cables, separate auxiliaryterminal boxes are supplied as required. Main and auxiliary terminal boxes to matchhazardous area requirementsMounting Hold down bolts Locking pins Jacking screws Shims Sole plates Anchor bolts Grouting moulds Separate steel framesHandling Lifting beams Shaft extensions for rotor removal Wooden packing for under-decksea transportation Tarpaulin packingABB / AMZ Synchronous Motors EN 08-200521

Factory Acceptance TestNumerous tests are performed on themotor components as they progressfrom one manufacturing stage to thenext. These tests include qualitymonitoring, inspections and insulationreliability evaluations. A set of finaltests is performed once all the partsand components have been integrated,in order to verify that the motormeets or exceeds the customer’srequirements. All tests are performedaccording to IEC-34 unless otherwisespecified. Testing according toNEMA MG 1, IEEE-115 or marineclassification society requirementsis available upon request. Checking of temperature detectors No load pointSpecial tests may be conductedto verify performance in specialconditions. They may, for example,be based on customer specifications,hazardous area or classificationsociety requirements.Such tests may include: Short circuit point Overpressure, leakage, andand space heaters Terminal markings and directionof rotation Axial play for unlocked bearings Bearing run Vibration measurement Testing of the excitation controller Overspeed test Auxiliary check Insulation resistance measurement Voltage waveform measurementafter dielectric test Visual in

2 ABB / AMZ Synchronous Motors EN 08-2005 The Global Power in Synchronous Motors ABB is the world’s leading supplier of synchronous motors and generators, with more than a century of ex