3. Structure &working principle

Greegoo Electric Co.,Ltd

Add:Jinye Mansion, Lvzhuang, Liushi, Yueqing, Zhejiang, 325604 P.R. China

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Vacuum Contactors

EVC8 Series

Tel: +86 577 62776000 Fax: +86 577 62776006

3.1 Structure and working principle

The high voltage main circuit and low voltage control circuit are

arranged in upper and lower sections. This arrangement mode looks

apparently, safe, reliable and convenient for installing and maintaining.

The contactor is mainly composed of vacuum arc-extinguishing cham-

ber, insulating frame, insulator, open/close operating mechanism, elec-

tro-magnet and bottom plate; while for the mechanical holding type, the

mechanical interlock mechanism should be assembled relatively.

The moving current-conducting rod of three-phase vacuum arc-extin-

guishing chamber is connected with the connecting lever by means of

three insulators; the connecting lever and the moving armature is

fixed/secured on the square axle. For the electric holding type, attract-

ing and releasing of the armature by the electro-magnetic coil drives

the making and breaking process of the moving contacts in the vacuum

switch tube. For the mechanical holding type, attracting of the moving

armature by the electro-magnetic coil drives the making process of the

moving contacts, and the mechanical locking mechanism keeps with

the state of closing; the breaking coil forces the mechanical locking

mechanism to release and the moving armature drives the moving

contacts to open by the function of opening coil. As making/breaking

process of the contacts is carried out in the vacuum space, therefore,

it has excellent switching characteristics, with long lifetime, both safe

and reliable. Its control circuits provide the rectifying equipment and

the changeover of picking up and holding of the electro-magnetic coil.

It also provides the auxiliary switch of 3a＋3b for the user.

3.2 Vacuum arc-extinguishing chamber

Inside the vacuum arc-extinguishing chamber of the glass or ceramic

enclosure is installed one pair of contacts, made of wear-resistant and

low current-cutting off material, which can satisfy both the breaking

performance and reducing the over-voltage caused due to the cutoff

current, and raise the lifetime of the arc-extinguishing chamber. Bellow

inside the arc-extinguishing chamber has the function of separating

the atmospheric air and making the moving contacts to be able to

make axial motion, thus cannot rotate the moving conducting rod;

otherwise the bellow will be damaged due to the twist of the rod.

WARNING: Vacuum arc-extinguishing chamber is the functional actu-

ating component of the contactor. Do not impact it by the external

force; otherwise the complete contactor will be damaged/wasted.