ABB V-Contact VSC Medium voltage vacuum contactors
The medium voltage V-Contact VSC contactors are apparatus suitable for operating in alternating current and are normally used to control users requiring a high number of hourly operations.
The V-Contact VSC contactor introduces the drive with permanent magnets, already widely used,experimented and appreciated in medium voltage circuit-breakers, into the worldwide panorama of medium voltage contactors.
The experience acquired by ABB in the field of medium voltage circuit-breakers fitted with drives with “MABS” permanent magnets, has made it possible to develop an optimised version of the actuator (bistable MAC drive) for medium voltage contactors.
The drive with permanent magnets is activated by means of an electronic multi-voltage feeder. The feeders differ according to the integrated functions and to the auxiliary power supply voltage.


Three bands of power supply are available with which all the voltage values required by the major international Standards can be covered.
Each feeder is able to take any voltage value within its own operating band.
All the contactors mentioned above are available,on request, in one of the two following versions.
SCO(Single Command Operated): closing takes place by supplying auxiliary power to the special input of the multi-voltage feeder. On the other hand, opening takes place when the auxiliary power is either voluntarily cut off (by means of a command) or involuntarily (for lack of auxiliary
power in the installation).
DCO (Double Command Operated): closing takes place by supplying the input of the closing command of the apparatus in an impulsive way.
On the other hand, opening takes place when the input of the opening command of the contactor is supplied in an impulsive way.

Fields of application
The V-Contact VSC contactors are suitable for controlling electrical apparatus in industry, in the service sector, in the marine sector, etc.
Thanks to the breaking technique with vacuum interrupters, they can operate in particularly difficult environments.
They are suitable for control and protection of motors, transformers, power factor correction banks, switching systems, etc. Fitted with suitable fuses, they can be used in circuits with fault levels up to 1000 MVA (VSC7 - VSC12)
Compliance with Standards
V-Contact VSC contactors comply with the Stand ards of the major industrialised countries and in particular with the EC 60470 (2000) Standards.
Approvals
Approval by the DNV, RINA and LL.RR shipping registers is foreseen.
Operating characteristics
• Ambient temperature: – 5 °C ... + 40 °C
• Relative humidity: < 95 % (without condensa tion)
• Altitude: < 1000 m s.l.m.
Main technical characteristics
• Chopping current value ≤ 0.5 A
• Maintenance-free
• Suitable for installation in prefabricated substations and switchgear both of the card (slim line) and traditional type
• High number of operations
• Direct checking of contact wear
• Long electrical and mechanical life
• Remote control
• Multi-voltage feeder
• Bistable drive of the type with permanent magnets
• Behaviour on power cut adjustable by the customer (instantaneous or delayed opening) in the SCO versions and, should the undervolt age accessory be required, DCO.
Interruption principle
IThe main contacts operate inside the vacuum interrupters (the level of vacuum is extremely high: 13 x 10-5Pa).
On opening, there is rapid separation of the fixed and moving contacts in each contactor interrupter.
Overheating of the contacts, gener ated at the moment they separate,causes formation of metallic vapours which allow the electric arc to be sustained up to the first passage through zero current.
On passage of zero current, cooling of the metallic vapours allows recovery of high dielectric resist ance able to withstand high values of the return voltage.
For motor switching, the value of the chopped current is less than 0.5 A with extremely limited overvoltages.
“MAC” magnetic drive
ABB has implemented this technology in the field of contactors on the basis of experience gained in the field of circuit-breakers with magnetic drive.
The magnetic drive adapts perfectly to this type of apparatus thanks to its precise and linear travel.
The drive, which is of bistable type, is fitted with an opening and a closing coil.
The two coils - individually energised - allow the drive mobile armature to be moved from one of the two stable positions to the other.
The drive shaft is solid with the mobile armature and held in position in a field generated by two permanent magnets (fig. A).
Energising the coil opposite to the magnetic latching position (fig. A) of the core, the magnetic field is generated (fig. B), which attracts and moves the mobile armature into the opposite position (fig. C).
Every opening and closing operation creates a magnetic field concordant with the one generated by the permanent magnets, with the advantage of keeping the intensity of the field itself constant during service, regardless of the number of opera tions carried out.