1 Summary

Earthing switches of series EK6 are determined for indoor installation and conform to the requirements of GB1985 and IEC 62271-102. They are fitted with snap-action operating mechanisms for positive high-speed closing and sufficiently dimensioned to conduct the rated short-circuit making current when closed under load. The speed of the snap-action closing operation is independent controls. The earthing switches are supplied as kits with a pre-assembled active part and corresponding earthing contacts supplied loose. Correct installation of these parts in a switchgear panel results in a functioning earthing switch. Routine tests toGB1985 and IEC 62271-102 are to be carried out at site accordingly.

2 Ambient Conditions

2.1 normal using ambient conditions

(a) Ambient air temperature: upper limit +40℃

                          Lower limit – 25℃  

Remark: allow to store and transport under – 30℃

(b) Altitude limit: under 1000m

(c) Relative humidity: under 90%

(d) Earthquake intensity: not higher than class Ⅷ

(e) the place should be without fire, explode danger, serious dust, chemical corrosion and strong shock.

2.2 special using ambient conditions

When earthing switch is used in different places of 2.1, users will rise up special requirements to manufacturer.

 

3 Technical Parameters

Model	Rated voltage(kV)	Highest working voltage(kV)	4S rated short time withstand current(kA)	Rated dynamic stable current (peak value) (kA	Making current(peak value)(kA)	Pole centers (mm)	Making speed  (m/s)	Main circuit contact resistence(μΩ)
EK6-12/31.5-210	10	12	31.5	80	80	210	﹥6	＜120
Ek6-40.5/31.5-280	35	40.5	31.5	80	80	280	﹥6	＜120

Remark: the pole centers can be changed according to customers' requirement

4 Instructions and Function

Earthing switches of series EK6 have three pairs of earthing blades which are located on the operating shaft and are freely movable. The pairs of earthing blades are electrically connected to each other by a short-circuiting bridge and to earth potential at the bearing brackets by two stranded copper conductors. Driver levers and toggle springs located between the bearing brackets are used to transmit the force during the switching process. Fixing the active part on a torsionally rigid switchgear panel wall or cross beam provides it with the necessary stability. The earthing contacts designed to suit the relevant switch type are to be bolted to the conductor bars supported on suitable insulating parts, e.g. pin type insulators, on the opposite side and parallel to each other, and the position adjusted until it conforms to that show in the dimensional drawings.

The earthing switch has a snap action closing mechanism which functions independently of the rotation of the drive shaft. The switching speed and torque achieved in this process are independent of the actions of the operating mechanism. In the opening process, in contrast, the toggle springs have no effect on the speed of contact separation. A ring lever or suitable manual or motorized operating mechanism with the necessary torque for the type of switch and an operating angle 90° can be fitted for operation of the switch.

Note: Always open earthing switches by turning until the stop is reached.