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无载开关“AT”系列-OFF-CIRCUIT TAP CHANGERS "AT" SERIES |
| 产品描述-INTRODUCTION |
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AT series off-circuit tap changers have been manufactured to be used in oil-insulated transformers and they have been designed for maximum compactness.
AT series off-circuit tap changers have been designed to be used in applications in which a low value of partial discharges is required.
AT series off-circuit tap changers are single-phase or three-phase.
AT series off-circuit tap changers are fixed point or bridge type.
AT series off-circuit tap changers are divided into ATV and ATC range:
On AT tap changers with 100kV rated voltage we install the shielding rings only on customer’s specific demand.
The control devices provided by AT series are the following:
1) handwheel control device with direct exit on the cover;
2) handwheel control device with low side exit and cone clutch;
3) handwheel control device with low transmission to men-height and cone clutch;
4) handwheel control device with transmission to men-height. |
| CONSTRUCTION CHARACTERISTICS AND MATERIALS |
The materials used to manufacture Comem tap changers have been chosen to give the best performance and reliability.
The insulating materials belong to class "E" in accordance with ISO 1642, DIN 7735, NF C36, Nema LI 1 1983 - BS standards.
The fixed and mobile contact are made of special brass and copper alloys so as to grant the best thermal, mechanical and wear performance in accordance with IEC 60214-1, IEC 60214-2 standards.
We took some measures to avoid the pyrolysis of the oil which causes problems on the electrical contacts of off-circuit tap changer. We used steel drive shaft, special gaskets and aluminium parts in order Comem tap changer can be used in tropical environments. |
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| CHECKS AND TESTS |
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Comem S.p.A provided for dimensional and working checks on all the parts and finished tap changers in order to
grant the best reliability.
All AT series tap changer have been manufactured in accordance with the following standards:
• IEC 60214-1: " Tap changers. Part 1: Performance requirements and test methods";
• IEC 60214-2: "Tap-changers - Part 2: Application guide"
The following type of tests - available on demand - have been carried out:
• check of maximum oil overtemperature limits;
• check of short circuit current strength;
• check of strength at industrial frequency and impulse;;
• check of partial discharges. |
