GE系列PDU原理文档.doc

Last Revised:December 2004This module contains the following sections: Section 1 - Overview Section 2 - NGPDU Physical Description Section 3 - NGPDU Service Overview Section 4 - NGPDU Electrical Specifications Section 5 - NGPDU Drawings Section 6 - NGPDU LEDs Section 7 - NGPDU Control Board Switches and Fuses1Overview The PDU provides a single location to connect input power for the entire CT system. Its function is to provide the following features to the System: Compensation means for a wide range of input voltages via tap selection Provide required system AC power from a single source Provide High Voltage DC power for x-ray generation Provide power for gantry axial rotation Provide a means for emergency shutdown of all x-ray and drives power circuits Provide system AC power circuit protection Provide an interface for an external UPS connection Meet the requirements of IEC601 for both radiated and conducted emissionsThe PDU is designed to comply with United States Federal Regulations and the European Medical Device Directive. It bears the certification marks of a United States National Recognized Test Laboratory with Canadian deviation or a Canadian certified test house. Each unit is identified as being in compliance by being labeled with the official mark(s) of each respective agency.While in the stand-by mode, the NGPDU does not generate sound levels in excess of 50dbA, when measured at a distance of one meter from the nearest cabinet surface, in any direction.2NGPDU Physical Description 2.1Mechanical Enclosure The enclosure has a front, rear and top access covers. The top cover is installed on the frame with a captive fastener in the middle of front edge. The front cover weighs less than 22 lbs (10 kg).A single full-width Lexan safety shield is provided under the front cover. It extends ” below the top front edge of the assembly to the bottom of all HVDC Supply components, including the PDU Control Board.The rear cover is held in place by two captive fasteners. To maintain a good high frequency ground between internal subassemblies, all internal metal surfaces are solidly grounded to each other.The enclosure is painted Mist Gray (GEMS Gray #1).2.2Component Locations The main input transformer is located in the rear accessible chamber near the bottom of the cabinet, allowing enough room for cable access beneath. For ease of installation and serviceability the remaining components for the HVDC Supply and AC Power Distribution are located on the vertical dividing panel behind the front cover. Refer to Table 1 below, for general component information. Items numbers in table appear in circles of Illustration 1.Table 1:Major Components ItemPart No.Name / DescriptionComments1 2326492NGPDU assemble 12326492(H-Power) non stockable2 2326492-3NGPDU assemble 32326492-3(H-Power 60) non stockable3 2354578Front Cover4 2354579Side Cover5 2354580Rear Cover6 2354581Top Cover7 2334820PDU Control Board8 2356067PDU IF BoardIF Bd(2326492-2 Qxi)9 2351483110A CB ASSYCB110235148415A BreakerCB211 235148540A BreakerCB312 235148610A BreakerCB413 235148740A BreakerCB514 229554416A BreakerCB615 229554520A BreakerCB716 229554332A BreakerCB5(2326492-2 Qxi), CB817 22955464A BreakerCB918 2351488100A ContactorKxg19 235148950A ContactorKtg20 235149018-32A ContactorKsv21 235149114-25A ContactorKss222351492200A FuseF1-3(2326492 H-Power)23 2351493100A FuseF1-3(2326492-3 H-Power 60)242113764-36uf / 370Vac CapacitorC1-62523514944600uf / 450V CapacitorC7, C8262351495Diode BridgeBR1272201229-2Power SupplyPS282391041Resistor AssyR292202215-2Emergency SwitchSW302286488LED AssyLED312396924Gantry Enable SwitchSW including LEDIllustration 1:Component/Physical Layout NOTE:For a larger version of the illustration, click on the pdf icon below:Media File 1:Component/Physical Layout 2.3Product Labeling 2.3.1Rating Plate The PDU has a rating plate permanently attached to the rear cover, near the top edge and approximately centered on the cabinet. It contains the following information:For Model 2326492:Manufactured forGE Medical Systems by (Vendor Name)Made in (Country of origin)Power Distribution UnitModel No. 2326492 / (Vendor model # if different)Serial No. _Input Voltage: 3 380 / 480 VLine Frequency: 50 / 60 HzInput Power:Momentary 150 kVA 0.85 PFContinuous 25 kVAWeight 770 lbs. (350 kg.)Mfg Date: _ (appropriate test house markings, e.g., UL, ETL, CSA or eq.)For Model 2326492-3:Manufactured forGE Medical Systems by (Vendor Name)Made in (Country of origin)Power Distribution UnitModel No. 2326492-3 / (Vendor model # if different)Serial No. _Input Voltage: 3 200 / 240, 380 / 480 VLine Frequency: 50 / 60 HzInput Power:Momentary 90 kVA 0.85 PFContinuous 20 kVAWeight 770 lbs. (350 kg.)Mfg Date: _ (appropriate test house markings, e.g., UL, ETL, CSA or eq.)2.3.2Auxiliary Rating Plate For ease of service identification, an auxiliary rating plate is also located inside the unit, in a visible location when servicing the unit from the front. It includes the GEMS model number and unit serial number.3NGPDU Service Overview 3.1Replacement Parts / Interchangeability All replacement parts required for servicing the PDU are directly interchangeable without need of any re-adjustment. Circuit boards and sub-assemblies are given unique part numbers and revisions are completely backward compatible. Any changes to form, fit, or function which affect interchangeability shall require the assignment of a unique part number.3.2Service Tools The PDU is designed so no special service tools are required. The assembly can be serviced with standard service tools.4NGPDU Electrical Specifications 4.1Primary Input Power The input power terminals accommodate #4 to #1/0 (fine strand) wire sizes. Ferrules are provided for the maximum wire capacity allowed. Input line fuses rated 100A per phase are used to protect the system. Dual element, time delay motor starting fuses are used.The primary input power terminations & fuses are mounted in a dedicated enclosure within the PDU. Bulkhead mounted, low inductance, feed through filter capacitors are connected in series with each of the three primary lines on the load side of the primary fuses. The capacitance of each device is 0.025F to ground.4.2Input Filtering Low inductance, AC filter capacitors rated for mains connection are installed in a floating wye configuration on the three primary lines, on the load side of the fuses. Each capacitor is rated at 6.0F.4.3Input Transformer The main input transformer is an indoor style, multiple winding, 3-phase isolation transformer. It has an open frame, varnish impregnated core & coil construction. It is suitable for continuous duty without requiring forced air-cooling. The insulation system used is UL, CSA, & IEC recognized for 180C (Class H) or better, and each transformer is labeled accordingly.4.3.1Magnetic Circuit The magnetic circuit is designed for nominal 50/60 Hz operation (47 to 63 Hz limits). It accommodates a daily variation of 10% input voltage, (i.e., 110% input voltage doesnt cause excessive exciting current and core losses). Under worst case conditions, the transformers peak inrush current is less than 1000A when properly connected and energized at 380 V, 50 Hz.4.3.2Primary All power for the CT System passes through the primary winding of the input transformer. It is protected by the primary input fuses described above.The primary winding is designed for delta connection. Voltage selection taps are provided on each phase to accommodate 20 volt steps over the input voltage range of 380 to 480 V. All leads are brought out to a panel for external voltage selection. Leads are designated as follows:Illustration 2:Compact PDU Primary taps The gap in the winding between sections is located at the electrical middle of the winding, i.e., 240vac from the “S” end. This feature allows the use of an alternate connection pattern for 200/220/240 volt input. In this configuration the PDU maximum momentary input rating is limited to 90kVa.NOTE:This connection is used with the 2326492-2 assembly only.The connection options are:System Voltage:200220240Lead Connections:1-61-51-4This winding contains three normally closed thermal cutout switches, one securely embedded in each phase coil. These switches are set to open at a nominal temperature of 150C. They are capable of interrupting 120 Vac, 1 A, contactor coil power.At shipment, the primary taps are set to the 480 volt connection.4.3.3Secondary #1 (designated as the “X” winding) Secondary #1 is a 208Y/120V wye connected power winding. The phase leads are labeled X1, X2, and X3. The neutral, labeled X0, is isolated and brought out for external connection to ground.Illustration 3:Secondary “X” Winding Configuration The full winding feeds general-purpose power to the CT system. The winding is protected at 40A per phase with a three-pole, 40A circuit breaker labeled CBSecondary #2 (designated as the “Y” winding) Transformer for Model 2326492-2 (86 turns total):Secondary #2 is a nominal 494Y/283V wye connected power winding. The phase leads are labeled Y1, Y2, and Y3. The neutral, labeled Y0, is isolated and brought out for external connection to ground.Illustration 4:Secondary “Y” Winding The #2 secondary winding provides x-ray & drives power to the system. The full winding powers the HVDC supply. This is a six-pulse unregulated DC supply, which feeds the X-Ray source. As such, the output current is rich in the non-triplen odd harmonics. In particular, it contains 35% 5th and 15% 7th harmonic with additional higher harmonics being substantially lower magnitude.The 440Y/254V taps feed an external Variable Speed AC Motor Drive. Assuming an 8% duty cycle, this drive produces an effective load current of 4.6A per phase. These taps are to be protected at 15A per phase with a three-pole, 16A circuit breaker, labeled CBShields Full width electrostatic shields are provided between the primary and secondary windings. These are made from 0.005” copper or aluminum foil, with a minimum 0.5” insulated overlap. Each shield is grounded to the core and frame with green leads as short as practicable. (The lead position and attachment method minimizes shield impedance to high frequency noise signals.)4.4AC Power Distribution A general overview of the AC Power Distribution of the CT system is shown in the diagram below.Illustration 5:AC Power Distribution NOTE:For a larger version of the illustration, click on the pdf icon below:Media File 2:AC Power Distribution 4.5General Purpose 120/208V AC Power Distribution 4.5.1Full Winding Protection The PDU Isolation Transformer, Secondary #1, supplies low voltage AC subsystem power. It is protected at 40A per phase with a three-pole, 40A circuit breaker. The full winding protection breaker is labeled CBUPS Interface A 10 position terminal strip, labeled TS4, is provided in the bulkhead for connection of an optional partial system UPS. This terminal block has compression type terminals approved for use with bare or stranded wire and is suitable for wire size 8AWG (8.5 mm2).Terminals TS4-1 through TS4-5 provide output power connection to the optional UPS. Terminals TS4-6 through TS4-10 provide the power connections back to the NGPDU from the UPS. Connections are as follows:Table 2:UPS Connection Terminal NumberSignal NameFunctional Description1CB3-APhase A, 120VAC power to UPS2CB3-BPhase B, 120VAC power to UPS3CB3-CPhase C, 120VAC power to UPS40VACNeutral (0VAC) to UPS5GNDSafety ground (G/Y) wire to UPS6UPS-APhase A, 120VAC power from UPS7UPS-BPhase B, 120VAC power from UPS8UPS-CPhase C, 120VAC power from UPS90VACNeutral (0VAC) from UPS10GNDCSafety ground (G/Y) wire from UPSJumpers shall connect terminals 1 to 6, 2 to 7, and 3 to 8 with the PDU loads connected to the outputs of terminals 6, 7, & 8. These jumpers will be removed in the field whenever an optional UPS is used with the system.4.5.3Circuit Protection AC power is distributed to the CT System via seven (7) separate branch circuits. These branches are protected by individual circuit breakers as follows:Table 3:Circuit Breaker BreakerRatingPolesPhaseLoad DescriptionCB216A3A B CAxial DriveCB410A1BCT Gantry Service OutletsCB5*40A1CCT Gantry Rotating LoadsCB616A1ATable & CT Gantry Stationary LoadsCB720A1AOperator ConsoleCB830A1BPET GantryCB94A1ANGPDU Control Power Supply*Table service outlet is limited to 10 amperes.4.5.4AC Power Output Connections The output connectors for AC power distribution to external subsystems shall be as follows:Table 4:AC Output Connectors SubsystemPDU Connector TypeGantry 40A / 15A, 3P, 5W Phonix UK16N labeled TS5-4 to 8. (30A, 1P, 3W Phonix UK16N labeled TS5-9 to 11 for PET Gantry)Console 20A, 1P, 3W Phonix UK16N labeled TS5-1 to 3.4.6High Voltage DC Power Supply 4.6.1Electrical Requirements The HVDC power supply is an unregulated, six pulse DC power source that feeds the high voltage subsystem used to generate x-rays. For model 2326492 the output voltage of this supply ranges between a maximum of 740VDC (No Load) and a minimum of 480VDC (minimum sag at a maximum step load of 225ADC). For model 2326492-2 the output voltage of this supply ranges between a maximum of 760VDC (No Load) and a minimum of 525VDC (minimum sag at a maximum step load of 100ADC).4.6.2Circuit Protection The input to the HVDC Supply is the 3-phase, output from the transformer secondary #2 as previously described. Each phase of this winding is protected by semiconductor fuse, labeled F1, F2, F3. Fuse sizes are indicated below.For model 2326492: F1, F2, F3 = 200 Amp, 660VACFor model 2326492-3: F1, F2, F3 = 100 Amp, 660VAC4.6.3Construction / Description The load side of the fuses is connected to a three-pole contactor, Kxg, having an AC1 rating of 100 Amps. The load side of the contactor is connected to the input of a 3 phase, full wave bridge rectifier / capacitor filter circuit. An auxiliary contactor, Kss, in series with a 20 ohms / phase resistive soft-start circuit is connected in parallel with the main contacts of Kxg. EMC Filter Capacitors - C4, C5, C6Low inductance, AC filter capacitors rated for mains connection are installed in a grounded wye configuration on the load side of Kxg. Each capacitor is rated 6.0 uF and has a minimum operating voltage rating of 330 VAC with a surge voltage rating of at least 2KV. If metal can style capacitors are used, their cans are solidly grounded to chassis metal and they are suitable for 330 VAC line to ground operation. Bridge Rectifier - BR1A 3-phase, full wave bridge rectifier rated 200 Amp, 1600V is used. The bridge rectifier is mounted to an aluminum heat sink, approximately 2 X 6 X 1/4. Aluminum Association Type 1100- F or equivalent aluminum is used. Thermal compound is used between the heat sink and rectifier and between the heat sink and chassis-mounting surface in accordance with the bridge manufacturers specification. HVDC Filter Capacitor(s)The DC output of the bridge rectifier is filtered with two 4600uf, 450 volt electrolytic capacitors connected in series across the output terminals of the bridge. A discharge resistor network for each capacitor is included on the PDU control board.4.6.4Output Terminations - TS2 HVDC output leads from the capacitors terminate in a three position terminal block, labeled “TS2”. In addition to the cable ground connection, a cable clamp is provided at the NGPDU bulkhead, which is used for strain relief and 360. termination of the shield of the field installed cable.Table 5:TS2 Terminal Block Terminal NumberSignal NameFunctional Description1“+”HVDC to CT gantry.2GNDAuxiliary safety ground (G/Y) wire to CT gantry.3“-”HVDC Return to CT gantry.4.7Axial Drive Circuit 4.7.1Electrical Requirements The 440V taps of secondary #2 are used to power an external variable speed AC motor drive used for axial rotation of the gantry. The drive uses a conventional three-phase full wave bridge rectifier input circuit. This produces strong 5th & 7th harmonic currents typical of 6-pulse rectification. The maximum load under gantry acceleration conditions is 15A.4.7.2Circuit Protection The circuit is protected at 15A per phase with a three-pole, 16A circuit breaker, labeled CBAxial Drive Contactor The CB6 circuit breaker feeds a three-pole contactor, labeled Ktg. The contactors 120VAC coil is controlled externally by the CT system. Auxiliary contacts on the contactor provide status feedback information to the system.4.7.4Output Terminations Output leads from the Ksv contactor terminate in a four position terminal block, labeled TS3. In addition to the cable ground connection, a cable clamp is provided at the NGPDU bulkhead, which is used for strain relief and 360. termination of the shield of the field installed cable.Table 6:TS3 Terminal Block Terminal NumberSignal NameFunctional Description1Ksv - 440APhase A, 440Vac power to Axial Drive.2Ksv - 440BPhase B, 440Vac power to Axial Drive.3Ksv - 440CPhase C, 440Vac power to Axial Drive.4GNDAuxiliary safety ground ( G / Y ) wir