Summary of Contents for PEC MACC
- Page 1 MACC MANUAL PROCESS ELECTRONICS CORPORATION 100 BRICKYARD ROAD MOUNT HOLLY, NORTH CAROLINA 28120 TELEPHONE (800) 421-9107 FAX (704) 827-9595 SALES@PECRECTIFIER.COM WWW.PECRECTIFIER.COM SOLID STATE CONVERTER...
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Page 2: Table Of Contents
PEC MACC DC Power Supply Index Section and Title Page 1. INTRODUCTION ........................4 1.1 Scope............................4 1.2 General Description of the MACC ....................4 1.2.1 Power Conversion System....................4 1.2.2 Cooling System ........................4 1.2.3 Control System ........................4 2. INSTALLATION ........................5 2.1 Inspection and Storage .........................5 2.2 Handling the MACC ........................6... -
Page 3: Section And Title Page
Section and Title Page 4. MAINTENANCE 4.1 Cabinet 4.2 Connections. 4.3 Control Connections 4.4 Control Checkpoints . 4.5 Cooling. 4.5.1 Power Components 4.5.2 Replacement of Diodes and Thyristors (SCR's) 4.6 AC1 Electronic Control Board (McTrigger). 4.7 Troubleshooting . 5. REPLACEMENT PARTS 5.1 Parts List It must be understood that these instructions cannot cover all details or variations on equipment, nor provide for every possible contingency in connection with installation operation or... -
Page 4: Introduction
General Description of the MACC The PEC MACC is an air cooled, DC power supply designed to give a specified output voltage and current to cover a wide range of applications. Its overall size and weight saves valuable floor space. -
Page 5: Installation
INSTALLATION Inspection and Storage As all units are shipped F.O.B., our plant, it is suggested that the shipping containers be removed and the converter inspected for possible damage during shipment. If any damage is found, the purchaser must handle the claim, and the carrier contacted immediately. -
Page 6: Handling The Macc
Handling the MACC The MACC unit must be handled at all times with the same care that would be given any piece of precision electrical equipment. Care must be exercised in lifting the converter. Weight distribution varies depending on the size of the cabinet. - Page 7 Figure 4-A Cabinet Size for 500 to 1000 Volt Output Model Figure 4-B Cabinet Size for 1500 Volt Output Model - 7 -...
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Page 8: Air-Cooled Converter
If the supply voltage or frequency differ from the rated input voltage or frequency, the PEC office should be contacted to advise the necessary changes before the unit can be operated. The converter should not be connected under any circumstances to a source which does not match the data plate rating without the approval of Udylite. -
Page 9: Dc Output Connections
2.5.2 DC Output Connections The DC terminal assembly is 1/4-inch x 4- inch copper bus bar, punched with a standard four hole pattern. See Figure 6. Additional bus required for the tank connection may be aluminum or copper. If aluminum, the bus should be plated at the connection ends to decrease contact resistance. - Page 10 Figure 8 Remote Control Converter Interconnection CAUTION The input wiring and installation should conform to the National Electrical Code, and or local codes as required. - 10 -...
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Page 11: Operation
OPERATION Component Operation 3.1.1 Magnetic Starter Three phase input power is applied to the converter through the magnetic starter. It also provides protection in the event of a major component failure or line fault. The power contacts are actuated by energizing a magnetic coil. A normally-open contact on the main starter, or contactor, is used to apply power to the magnetic coil, holding the power contacts in until the coil is de-energized and the power contacts open, removing the converter from the power line. -
Page 12: Silicon Controlled Rectifier
3.1.3 Silicon Controlled Rectifier The silicon controlled rectifier (SCR) is a regenerative semiconductor switch. See Figure 10. It is a silicon diode with a third element, a gate, which controls the flow of current through the SCR. The gate determines the point in each half cycle when the SCR will "fire"... -
Page 13: Main Transformer
In the MACC the SCR’s are connected in the back-to-back arrangement and placed in the line. The transformer primary is connected in a solid delta. See Figure 13. The DV/DT and pulse transformer boards provide both the controlling gate-cathode pulses for varying the converter output, and DV/DT protection for the SCR from line voltage transients. -
Page 14: Diode Assembly
3.1.5 Diode Assembly The diode assembly of the converter is completely solid state employing parallel sets of silicon diodes as the rectifying elements. See Figure 14. A six-phase single way rectifier connection is employed. The shunt provides the current feedback for the control and also the signal for the indicating ammeter. -
Page 15: Cooling System
(approximately 230 ° F). Cooling System The MACC converter is air cooled, requiring very little maintenance. The air enters the cabinet through a screened opening in the bottom. The heated air generated from the power components rises and exits through the top of the cabinet. - Page 16 Protection of the converter from DC overloads is provided for by the automatic current limiting. Any decrease in load resistance above the converter current rating will result in a decrease of output voltage and the converter output current will be limited at its maximum rated current.
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Page 17: Converter Operation
For example, the output of a 1000 Amp @ 12 Volt converter will be held constant -+10 Amp from 1.2 Volts to 12 Volts. The voltage limit control is designed to reduce load burning due to overvoltage and prevent power interruption to the load. Any increase in load resistance will result in a decrease of output current and the converter will be limited at its rated voltage output. -
Page 18: Automatic Average Current Density Control With Current Limit Adjustment Procedure18
3.3.3 Automatic Average Current Density Control with Current Limit Adjustment Procedure All converters are shipped in the voltage mode of control unless otherwise specified at the time of order. The automatic average current density control must be used with the voltage mode of control for proper operation. -
Page 19: Automatic Current Control With Voltage Limit Adjustment Procedure
5. Reverse steps 3 and 4 for conversion back to voltage mode of control. 3.3.6 Turn-Off Procedure The MACC may be shut off by two methods: 1. For operation without interrupting the starter or contactor, switch the "control on-off" switch to the "off"... - Page 20 MAINTENANCE The PEC MACC solid state converter has been designed for minimum maintenance. A regular schedule of periodic checks should be set up to keep the converter in peak operating condition. All components requiring normal maintenance are easily accessible from the front and rear of the converter.
- Page 21 Cooling Keep air passages in heat sinks and transformer free of dust build up and corrosive deposits. 4.5.1 Power Components All accumulated dust, dirt, and particles of foreign matter should be removed at each periodic inspection. A soft bristled brush should be used to clean off the power heatsinks, SCR’s diodes and main transformer.
- Page 22 3. Identify SCR terminals. See Figure 20. 4. Place the red lead and black lead in circuit back-to-back across the SCR combination as shown in Figure 21. This tests SCR1. NOTE: No light should register. If the light comes on, one of the two SCR’s is shorted.
- Page 23 AC1 Electronic Control Board Operating Status Characters Troubleshooting The MACC converter is designed for ease of troubleshooting. Control checkpoints are brought out to the main terminal strip. Power checkpoints are readily accessible in the main cabinet at the starter panel. Maintenance personnel should have a basic knowledge of electricity and be acquainted with the electrical diagrams and physical location of components within the converter.
- Page 24 Troubleshooting Chart Problem Probable Causes General Converter does not start 1. Main switch not closed 2. Line fuse open 3. Loose connection at push-button 4. Open overload device 5. Open starter coil 6. Control circuit fuse open Converter starts but drops out when start button is 1.
- Page 25 When ordering replacement parts, give the model number and serial number of the unit as shown on the data nameplate, a description of the parts and the quantity desired. If further information is desired, contact your PEC salesman, the service department, or write to: Process Electronics Corporation.
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