SERIES TAP-CHANGER

Transcription

1 SERIES TAP-CHANGER Main characteristics This is an off-circuit tap changer. It means DO NOT OPERATE WHILE THE TRANSFORMER IS ENERGISED. Main characteristics of this tap-changer series are: dimensional compactness only 4 components to assemble for customers only one rotative movement self centring moving contacts They can be used either in mineral or synthetic oil, in silicon liquid or in eco-fluid. In the catalogue are performed the standard appliances and devices. On request is possible to satisfy special requirements as: - multi-stage tap changers - mirror like assembling - insulated intermediate clamp for different dimension of the shaft L - special executions Mechanical characteristics On the tap-changers type 090 fixed contacts are mounted in the fixed strips perpendicular to the support, while in the moving strips are installed moving contacts. The fixed strip is bolted to the bearing in which the moving strip slides, driven by a pinion. Metallic parts The metallic parts that mainly compose drive control of the tap-changer are normally made of stainless steel and brass. The brass parts exposed to external environment on request can be made of stainless steel (see different solutions on page ). Polyamide parts Lower part of the bearing gear and control knob are normally made of polyamide. On request, control knob can be supplied made of aluminium and the eventual protective cover in Zama 15. Changing over The knob must be inserted only when the 2 milled centring parts have been aligned. One is positioned on the shaft and the other is positioned on the metallic section of the support. To change the position, after having released the locking-device up to its stroke-end, you only have to rotate the knob without pulling it up and continue the operation up to reach the wanted new position, than screw the locking-device. The knob can be padlocked in any position by utilizing the appropriate rectangular hole on the positioning-ring and inserting the shackle of the padlock (6 mm max.) in the corresponding hollow space of the knob. For more information please request the operation instruction manual to C.a.p.t. Oil tight Oil and silicon oil sealing is obtained by the use of O-ring gaskets. Fixed contacts Made of copper with following internal diameters: Ø = 2,1 mm for 10 A rating, Ø = 3,1 mm for 30 A rating, Ø = 5,1 mm for 60 A rating. The connection of the conductors is provided by crimping of flexible cables. It can also be carried out by tin soldering, if so, care should be taken to avoid damages on the insulation parts. On request contacts can be silver-plated. Moving contacts They are made of brass with wave shape to obtain an higher contact section (lower rise-temperature) and aid the tap changer self-positioning. On request, contacts can be supplied silver plated.

2 Voltages Voltage classes are allowed for: voltage max Earth withstand voltage class permissible Industrial frequency 50 Impulse 1/50 voltage Hz kv kv kv kv According standard IEC e IEC Currents 10 A 30 A 60 A. Tests On tap changers, following our internal quality procedures, are carried out the routine tests and on some prototypes the type tests like rated short duration power frequency voltage tests, lightning impulse voltage, temperature rise test at rating current, short-circuit current test according to IEC standards. The insulating materials used are paper laminates and phenoplastic resins of E thermal class. Codes To identify tap changer type by series and code, proceed like example below reported: SERIES: 090 CODE: = type 07= bearing length L 70 mm 2 = voltage 20 kv 3 = current 30 A 6 = number of positions n 6 BEARING STANDARD LENGTH: mm POSITIONS: standard from 3 to 7 positions, some kinds from 3 to 6. Please also specify type of control knob (see pages , , ) Dimensions Dimensions reported in the following pages are in millimetres (mm). Modifications In case we need to modify some particulars, in order to improve the quality of our products, CAPT firma reserve an option to change without a previous warning. Substantial modifications will be surely communicated. Treatment the oven and / or under vacuum and lubrication It is recommended that the treatment is carried out at a maximum temperature between C. After the treatment, before using the tap changer, you must lubricate carefully all the fixed and moving contacts of the tap changer, or alternatively, place the tap changer together with transformer active part in oil-filled transformer tank. Wait until the tap changer has come down to environment temperature before performing the first operation. Contact CAPT technical office when carrying out drying procedures at higher temperatures, or when carrying out special treatments. Maintenance (for the end-user) The tap changer does not require special maintenance. If the tap changer remains unused in a single position for a long period of time (months) during the maintenance of the transformer and with the transformer de-energised, we recommend to perform a series of operations on all the positions in order to clean the surface of the contacts. (see IEC and 9.1.3)

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