Operation and Maintenance Instructions for Dry Type Transformers
13Pages

41410 Gebze - KOCAELi - TURKEY info@sonmeztrafo.com.tr - www.sonmeztrafo.com.tr

INDEX Page 6.0 REMOVING FROM SERVICE 11

A transformer manufactured by STS, is designed, manufactured and tested with the latest technology and with strict quality control so as to ensure a long and problem free service. This manual must be read carefully before unpacking the equipment. It contains important information including safe handling, installation and maintenance instructions. This guide covers general recommendations for the operation and maintenance of dry type transformers. The successful operation of these transformers is dependent on proper installation, unloading, and maintenance. Dry type transformers require...

Materials and Components that are liable to be exposed or handled in normal operation and maintenance and which present any hazard to health are covered here. In addition to the instructions given in this manual, IEC/ANSI/equivalent standards and local regulations must also be referred for other details regarding the design, materials and performance. A list of standards applicable to distribution and power transformers is given as below; and Maintenance of Dry-Type Transformers ANSI C57.94 IEC:60905 Additional Information or suggestion will be given on request to STS. Dry Type transformers...

Units lifted from the top core clamps will sometimes require that the top cover or part of the cover be removed. Rigging crew must be experienced in lifting and moving of heavy electrical equipment. CAUTION: Dry type transformers should be maintained in an upright position when being moved. No attempt to handle a transformer in any other position should be made without first Because of their high centre of gravity, dry type transformers are subject to tipping over during handling. Care during handling will prevent equipment damage and/or personnel injury. Core and coil units should be...

The installation will be simplified if an outline drawing is requested. By studying the overall, mounting and terminal dimensions, it is possible to plan the installation with an orderly arrangement of connections.Core and coil units (without enclosure) usually have mounting and terminal dimensions to suit the customer's enclosure. That enclosure should give protection to the coils and have adequate clearance and sufficient ventilation openings. The manufacturer should always be consulted to determine these requirements. Top covers may be designed for cable entry or exit with bolt-on cover...

C. Make sure there is a properly dimensioned ventilation system in the room where the transformer is installed. (Take higher load losses into account under AF operation D. Unpack and remove parts that have been packed separately for transportation, such as connecting leads, control boxes, temperature control relays etc., and mount them (if there are) E. The undercarriage must not be dismantled from the bottom yoke clamping beams F. If protection enclosures have also been delivered, mount them according to the instructions enclosed with them. (If necessary) G If there is to be a long time...

CAUTION: The HV cast resin windings are insulated by a coat of cast resin, but they are not safe to touch in the sense. This means that work on the Transformer or in its immediate vicinity is only permissible when the transformer is off-circuit and earthed. WARNING: All protection relays must be connected to circuit breaker before energizing 33 Electrical Connection, Grounding The leads and connectors for the electrical connection of the reactors, the round wiring and all related hardware is usually not included in the scope of supply. As much as possible, the connecting leads are to be...

Before connecting the load, de-energize the transformer and arrange to monitor voltages and currents on LV side. Connect the load and energize the transformer. Then while monitoring the voltages and currents, increase the load. The voltages and currents should change symmetrically. If in doubt, de-energize the transformer and contact factory. The maximum continuous load a transformer can handle is indicated on the nameplate. However, many specially designed units have specific load capabilities designed into them. If there is any question concerning the load capability of the unit, the...

After installation, the output voltage of the transformer should be checked at some safe access point on the load. Never attempt to check the output voltage at the transformer since dangerous high voltage may be present within the transformer enclosure. When the output or load side voltage requires adjustment either up or down, the percentage tap j umpers found on the front surface of the coils must be changed in all phases. Consult the Transformer diagrammatic nameplate for information on what tap must be used to correct for high or low incoming line voltage or for voltage drop in the...

6.0 REMOVING FROM SERVICE If a unit is to be off more than 24 hours, provisions should be made to prevent the core and coils from taking on moisture. Refer to "Storage" Section 2.4.If the unit is to be moved, it will be necessary to replace the core and coil hold-down bolts and any shipping braces used for first shipment to protect the assembly during movement. Transformer failures may occur in either the electric, magnetic or dielectric circuits. Reduced or Zero Voltage Excess Secondary Voltage Coil Distortion Insulation Failure Breakers or Fuses Opening High Voltage to Ground - Continuous...

High Exciting Current High Core Loss, - Unrated Frequency or Harmonics - High Input Voltage - Core Clamps Loosened in shipment or handling - High Input Voltage - High Input Voltage - Shorted Turns - High Input Voltage - Damaged Core Insulation Failure Solid Insulation Material Failure Burned Insulation Lightning Surge Broken bushings, taps Breakers or Fuse Open - Switching or Line Disturbance - Insulation Failure If any of the above symptoms are noticed, the transformer should be immediately removed from service. Immediate attention may save a large repair bill. Many times the trouble can...