ABSTRACT
Revisions Date Prepared By Approved By Purpose
1.0 Design:
NOTE: The following specification is provided as a standard. Units being provided shall be in full compliance with this document unless an Exceltec International, hereafter referred to as EIC, client specification is provided. In this case, the client specification has precedence over areas which conflict. Supplier is to make EIC aware of all such conflicts and EIC will then instruct the supplier on how to proceed.
1.1 Units shall be suitable for indoor use and shall be cooled by means of forced air, unless stated otherwise in the project specification list. These units are to be used in electrochemical duty, as defined in ANSI standard C34.2. The equipment defined in this specification will be installed in a Tropical Environment, and is expected to operate with minimum supervision and maintenance.
1.2 Ratings:
Input: Per Project
Output: Per Project
1.3 Rectification Circuit Design:
Vendor Standard
1.4 Control:
1.4.1 Constant current from O to 100% of rating shall be achieved by thyristor phase control using a 10 turn pot. Output shall be within (+ /-) 1% over the combined effects of 50 to 100% DC output voltage at rated ambient temperature range and (+ /-) 5% AC input line voltage variation.
1.4.2 Triggering circuits shall be inherent timing balance within 50 microseconds, and shall be sensitive to power system distortion. Trigger shall inhibit output on the loss of an input phase.
1.4.3 Gate trigger lockout shall be activated from either a front panel switch, or an interlocking contact from the process control system.
1.5 Environment:
Continuous operation is to be expected under maximum ambient conditions of 40°C with 100% relative humidity. The units will be located indoors and may be shutdown for significant periods with high humidity. The above shall be considered standard unless stated otherwise in the project specification list.
Strip heaters shall be provided in each cabinet, which will be automatically energized on shutdown of the units. Protection against excessive heating shall be provided by means of a thermostat with a minimum range of 20°C to 60°C. Input power to the strip heaters shall be protected by circuit breakers. Space heaters shall utilize an independent power feed for supply and logic.
1092.0 Construction:
2.1 Transformer:
2.1.1 Dry type air cooled, 130°C maximum rise.
2.1.2 Insulation class H.
2.1.3 Windings primary and secondary use electrolytic grade copper.
2.1.4 Core— grain oriented steel, grade M6 or better.
2.1.5 Coils—Vacuum impregnated, epoxy coated.
2.1.6 All secondary connections shall be controlled in location, so that all like transformers are interchangeable, and a replacement may be installed at a later date with minimum interference.
2.1.7 The transformer shall conform to the requirements of ANSI standards C57.12.0l and C57.18 for electrochemical duty.
2.1.8 The transformer shall be permanently tagged with the transformer /rectifier unit serial number.
2.2 Cabinet:
2.2.1 Each cabinet shall be provided with a copper grounding lug of sufficient size.
2.2.2 Transformer cubicle shall meet NEMA 1 standards, with sufficient removable hinged access doors to permit service of any component without prior disassembly of any other components. All ventilation openings shall be fitted with fine mesh screens to prevent the entrance of rodents, large insects, or debris. Top ventilation opening shall have means of connecting duct work for purpose of exhausting heated air.
2.2.3 Control section shall meet NEMA 4X standards. The control space shall be of sufficient size as to facilitate service. Provision shall be made for the purchaser’s cable/ conduit entrance from either the top or bottom. Twenty percent of the panel space shall be left clear for future use. All components shall be attached in a manner in which they can be removed without removing the back pan.
2.2.4 EIC paint specification TS-025 shall apply.
2.2.5 Removable intake air filters that may be cleaned shall be provided
2.3 Rectifier Section:
2.3.1 Conductors shall be electrolytic grade copper of at least one square inch per 1250 Amps in each path for a forced air unit. For a sealed cooling unit, 1000 amps shall be utilized.
2.3.2 Power semiconductors shall have blocking voltage ratings of a minimum of 1200 volts, but at least 10 times the maximum DC voltage output under any conditions. Sufficient 110 cooling shall be provided to keep the maximum case temperature at least l5°C below the maximum rating for the device at rated current and at rated maximum coolant temperature.
2.3.3 Secondary power semiconductors shall be individually fused with current limiting fuses of the appropriate rating to isolate a faulted path without further damage to the unit.
2.4 Cooling System:
2.4.1 Cooling of the power components is by forced air, unless otherwise stated. Power semiconductors shall be mounted on the properly sized, anodized or iridited aluminum heat sinks.
2.5 Wiring:
2.5.1 Control wiring shall be of industrial quality, rated at 105°C or better. Wire shall be rated for 600 V and the size shall be 14 awg or larger, except for thyristor gate leads. Conductor shall be fine stranded tinned copper and insulation shall be PVC. Wire shall be UL listed. Manhattan style #M216 is preferred.
2.5.2 Terminations shall be by full tongue compression type terminals that provide a gas-tight connection, and have insulated compression sleeves to grip the wire insulation, or industrial grade clamp type terminal strips. Alternatives may be utilized if approved by an EIC engineer.
2.5.3 All wiring shall be labeled with permanent wire number markers, with a consistent numbering scheme. All wire numbers shall be shown on the electrical drawings. Wire numbers for a series sequence of circuit elements shall increase by one for each element passed through.
2.5.4 No more than two wires shall be landed on any termination point.
2.5.5 Wire ducts shall be used to organize and route control wiring. Proper routing shall provide separation between AC control and signal wiring. Wire ducts shall be sized so that the enclosed wiring consumes no more than 50% of the total available space.
2.5.6 Power wiring shall be of a size and insulation level appropriate to its application.
2.5.7 Equipment should be assigned tag numbers and be indicated with engraved plastic tags (Gravopoly) and attached by stainless steel screws. Tags should be white with black lettering. Tag numbers should correspond with all drawings. Alternate tagging methods may be utilized if first approved by EIC.
1112.6 Terminal Blocks:
2.6.1 All wiring for external field connections shall be terminated on a minimum number of conveniently located terminal blocks.
2.6.2 Terminal blocks shall be mounted so that sufficient clearance shall be provided for terminal marking, wire insertion and removal, and for the purchaser’s wiring connection.
2.6.3 Terminal blocks shall be of adequate size and shall be designed to receive purchaser’s incoming control cables.
2.6.4 A minimum of 20% spare positions shall be provided on all terminal blocks.
2.7 Controls:
2.7.1 General service auxiliary control relays shall be of an octal base, plug in type sealed design. They shall be IDEC or equal. Only one contact of each form C pair is to be utilized. Vendor may utilize PLC logic if approved by EIC.
2.7.2 Dry circuits (current < 50 mA, voltage < 30 V) must be switched by relays rated for the application, IDEC type RR3PA-UL or approved equal.
2.7.3 Push buttons, switches and lights shall be industrial quality, oil tight construction suitable for NEMA 4X application.
2.7.4 Electronic controls must be of printed circuit construction. They must also be mechanical locking, and have corrosion resistant contact materials.
Any edge connecting circuit boards must have a system for mechanically securing the boards and have a corrosion resistant plating system for the connecting edge, such as Ni or Au. All electronic boards shall be completely tropicalized before installation. If any board adjustments are made during testing these areas should be touched up.
2.7.5 Proper protection (i.e., fuse, circuit breakers) shall be provided for all equipment as dictated by the National Electric Code.
2.8 Tropicalization:
All electrical equipment, internal bus bars, and their enclosures shall be tropicalized. Secondary wiring, coils, and other insulations that are not fungus resistant, shall have a fungus resistant coating applied, except where such coatings would interfere with the proper operation. In such cases, the part shall be inherently fungus resistant. Use Dolph’s Synthite AC-279-7s Clear Air Drying Anti-fungal Varnish or EIC approved equal.
2.9 Motors:
All motors shall be totally enclosed fan cooled (TEFC) rated for the design ambient conditions. Insulation shall be Class F Continuous Duty.
1123.0 Protection and Metering:
3.1 Design:
Vendor shall be responsible for proper protection coordination and shall supply to EIC coordination curves.
3.2 Protection:
3.2.1 Circuit protection shall be supplied as follows:
3.2.1.1 Fuses or an incoming power circuit breaker shall be a manually operated type with an under-voltage trip. Design shall be sized to correctly protect the transformer/ rectifier.
3.2.1.2 Auxiliary power shall be protected by fuses or circuit breakers which are manually operated type. Individual fuses or circuit breakers should be provided for the 110/120 VAC control power and for the space heaters.
3.2.1.3 Circuit breakers shall be of the indicating type providing ON, OFF, and TRIPPED positions of the operating handle. Multiple breakers shall be designed so that an overload on one pole shall open all poles.
3.2.2 Instantaneous AC over-currents in excess of 150% rated input current shall immediately inhibit thyristor firing pulses. Removal of the over-current condition shall allow a smooth ramp recovery of output.
3.3 Alarms and Shutdowns:
3.3.1 Each of the following conditions shall be indicated locally and cause shutdown. These indications shall be latching indications, which are reset by an acknowledge push-button. A shutdown condition causes the thyristor triggering to be inhibited, or the primary AC circuit breaker to be opened. A test push-button should also be provided for periodic testing of all lamp indicators. All alarm and shutdown circuits shall be designed using Fail Safe logic.
3.3.1.1 AC over-current trip. A non-thermal, adjustable over-current relay shall be provided, with any required current transformers, which shall trip the unit for any input phase current greater than 15% above the continuous rating of the unit.
3.3.1.2 Semiconductor fuse failure shutdown. Visual indication of individual failed devices shall be provided.
3.3.1.3 Semiconductor over-temperature shutdown (one sensor for each semiconductor assembly).
3.3.1.4 Transformer over-temperature shutdown (one sensor for each phase).
3.3.1.5 DC over-voltage shutdown, set at 105% of rated output.
1133.3.1.6 DC over-current shutdown, set at 105% of rated output.
3.3.1.7 Blower/Fan failure overload trip.
3.3.2 Remote indication shall be provided by means of a Form C isolated contact for each of the following functions.
3.3.2.1 Rectifier On condition (AC Power Supplied).
3.3.2.2 Tripped Fault Relay Contacts.
3.4 Metering:
The following meters shall be provided as a minimum on each unit. Meters shall have an accuracy of + /2% of full scale. All required instrument transformers shall be supplied.
3.4.1 DC Ammeter.
3.4.2 DC Voltmeter.
3.4.3 Elapsed running time meter.
3.5 Panel Controls:
The following panel controls will be mounted on the control cabinet of each individual unit:
3.5.1 Auxiliary power (circuit breaker or fuses)
3.5.2 Current control potentiometer. One turn unit with indicating knob, scaled 0-100% for Oto rated output current.
4.0 Quality Control and Testing:
4.1 Documents:
4.1.1 Project schedule. Within two weeks of receipt of order, the vendor shall provide an estimated project schedule showing the anticipated dates of major events in the project.
4.1.2 Approval drawings. The following drawings are required for customer approval, before start of construction. For the purpose of scheduling, assume 8 weeks from submittal for drawing approval. One reproducible Mylar with a D size border and 1/8” text is required during each submittal stage.
4.1.2.1 Mechanical outline drawing showing detailed cabinet outline with dimensions, power and control entry locations and dimensions, service access, control locations and panel layout, and provisions for moving the equipment.
4.1.2.2 Electrical schematic drawings showing the closeup wiring, detailing all protective circuits and rectifier control logic.
4.1.2.3 Bill of materials showing component specifications of all major components such as power semiconductors, protective relays, connectors, fuses, etc.
4.1.3. Final drawings. One reproducible with D size border and at least 1/8” text shall be submitted of the following drawings.
4.1.3.1 Mechanical outline and installation drawing.
1144.1.3.2 Major component layout and service access drawing.
4.1.3.3 Internal schematic diagram(s) showing the power circuit, protection circuits, controls, customer interface, and metering circuits. All wire numbers shall be shown. Drawing formats and symbols shall comply with ISA Standards and IEEE Standards for electrical circuits.
4.1.3.4 Field installation wiring diagram, showing all required field terminations, terminal locations, terminal numbers, and wire sizes.
4.1.3.5 Electronic control schematic and layout drawing.
4.1.3.6 Instruction manuals. Specified copies shall be supplied, containing the following information. Note that EIC standard vendor requirement is for three (3) copies plus the amount specified by our customers. Past history has shown that 12-18 copies are required.
4.1.4 Installation, Operating, and Maintenance Manual. The specified number of copies shall be submitted after the draft copy is approved. Manuals should contain the following as a minimum.
4.1.4.1 Equipment description, layout and operation.
4.1.4.2 Maintenance instructions.
4.1.4.3 Electronic controls and testing.
4.1.4.4 Complete Bill of Materials showing manufacturers and ratings. Copies of manufacturer’s catalog pages or data sheets must be supplied. Supplier’s correct part numbers should be included.
4.1.4.5 Complete detailed test reports, as described elsewhere.
4.1.4.6 Certified As Built drawings as described in Section 4.1.3 should be supplied as part of this manual.
4.2 Inspection:
4.2.1 In-process inspection. EIC reserves the right to inspect progress on this project at any time.
4.2.2 Final inspection shall be witnessed by EIC, or their representative, at full load of one unit. The vendor shall have completed a full load heat run on all units prior to this witness test. Vendor shall notify EIC at least 2 weeks prior to that point of the test schedule. This inspection may be waived by EIC.
4.2.3 Test reports. Test procedures and report forms shall be submitted in detail to EIC for approval prior to testing transformers and rectifiers. At least 2 weeks shall be allowed for this approval process.115
4.2.4 Final test reports shall be submitted to EIC after inspection and test.
4.3 Transformer tests:
4.3.1 Transformer tests shall be done in accordance with ANSI standards C57.12.01 and C57.18. Test reports on each transformer shall be traceable to the unit in which it is installed. A copy of the transformer test report shall be included in the instruction manual for that unit.
4.3.2 Type tests. The following tests shall be performed and noted on the test report on one transformer, prior to installation in the rectifier units.
4.3.2.1 Excitation loss.
4.3.2.2 Copper loss.
4.3.3 Unit tests. Each transformer shall be given the following tests prior to installation in the rectifier units. These tests are to be noted on the test report and shall be traceable to the transformer/ rectifier serial number.
4.3.3.1 Dielectric test.
4.3.3.2 Ratio test.
4.3.3.3 Noise level should not exceed 85 dBA. Supplier should guarantee this in writing.
4.4 Electronics:
4.4.1 Burn in tests. Each electronic control board shall be given an operating, 2-hour burn in test, at an ambient temperature of 70°C. Alternate burn in procedures may be acceptable if submitted for approval.
4.4.2 Documented tests conforming to written procedure approved by EIC shall be performed on each circuit board, both before and after the burn in test. Some method of board traceability must be provided.
4.4.3 Traceable calibration data shall be provided for any control requiring calibration.
4.5 Unit Tests:
4.5.1 The following tests shall be conducted in accordance with ANSI standard C34.2. Copies of all test reports shall be included in the instruction manual.
4.5.2 Type tests: These tests shall be conducted on one unit of each design, prior to the witness test and shall be documented on the general test report.
4.5.2.1 Power losses.
4.5.3 Unit tests: These tests shall be conducted on each unit, and documented on the unit test report.
4.5.3.1 Dielectric tests on each independent circuit section, i.e., high voltage, DC output, AC control, protection circuits, etc.
4.5.3.2 Functional tests on all protective and control circuits.116
4.5.3.3 Full load test —Semiconductor case temperatures are probed and recorded after one hour of operation.
4.5.3.4 Full current and full voltage tests per ANSI standard C34.2.
4.5.3.5 Temperature rise at full load. Temperature recordings shall be taken of transformer windings, semiconductor cases, magnetic cores, and the control environment.
