Typical Specifications
Linear Puffer, Overhead Switches
Two Position

This specification covers the requirements for manual load break SF6 linear puffer (LP) style switches for overhead applications.

A. SWITCH CONSTRUCTION
All switch components and entrances shall be assembled in a single welded, mild steel tank. Entrances shall be internally connected by copper wire ropes and copper bus capable of handling momentary and continuous current duty. The protection degree of the switch tank shall be IPX7 rated. Switches shall be shipped filled with SF6 gas at approx. 9 psig (60kPa).

B. DESIGN RATINGS AND STANDARDS
Switches are to be designed, tested, and built per applicable sections of ANSI and IEC standards. Certified test reports shall be provided. The manufacturer shall be ISO 9001:2000 and 14001 certified. The switch assembly shall be rated:

C. SWITCH OPERATION
Each switch shall be equipped with an internally mounted rotary type operating mechanism capable of providing quick-make, quick-break operation. The mechanism must be capable of delivering sufficient torque and shall be provided with latches for each position. The mechanism shall use compression type springs to assure long life and reliability. All switch positions are to be clearly identified and padlockable. The operating mechanism shall be actuated from outside the switch tank by an external operating handle. The operating shaft shall be made of stainless steel for maximum corrosion resistance. A double “O” ring type operating shaft seal shall be used for a leak resistant, long life seal. Ambient temperature range shall be -30°C to +40°C (-22° F to +104°F).

D. SWITCH CONTACTS
Switch contacts shall be linear puffer style tulip-bayonet design and made of plated, high-conductivity copper alloy with arcing tips of copper/tungsten alloy. The contacts shall be designed such that arcing does not occur in the area of main current interchange and contact pressure will increase with increasing current flow. The contact nozzle shall have a converging/diverging geometry which improves the flow of SF6 into the arc zone. Contact travel shall be three inches and have sufficient open contact separation to assure efficient arc extinction and to withstand field DC testing levels and maintain BIL levels. The stationary contacts shall be supported independent of the cable entrance bushings. Temperature rise shall not exceed ANSI C37.71 and IEC 265-1 standards for this type of device.

E. STANDARD COMPONENTS
For a manual switch the following shall be included:

- Eleven gauge mild steel tank painted light gray with stainless steel and brass fasteners

- Two lifting eyes

- Crossarm bracket and mounting hardware

- Grounding provisions

- Gas pressure gauge and fill valve

- Three line diagram and corrosion-resistant nameplate

- Spring operator

- Manual operating handle

- Position indicator

- Padlock provisions for open and close positions

- Porcelain bushings with copper conductor and hoodnut

- Lightning arrester provisions

F. MOUNTING
Switches shall be equipped with:

- Crossarm mounting kit

- Polemount bracket (horizontal)

- Polemount bracket (vertical)

G. OPTIONAL COMPONENTS (check)
The following options shall be supplied:

___ Stainless steel tank

___ Low pressure warning device

___ SF6 density switch

___ 4/0 brass ground lug

___ NEMA 2-hole aerial lugs

___ NEMA 4-hole aerial lugs

___ Clamp style aerial lugs

___ Overpressure relief device

___ Wild life protectors

___ Surge arresters

___ Potential transformers

___ Current transformer (600:5) (500:1) (1000:1)

___ Automatic transfer control for 6-8 second transfer

___ Down rod operator kit that does not include rods

___ Motor actuator

___ Analog voltage sensors

___ 600A porcelain bushings with copper rod

___ 600A apparatus bushing with elastomeric insulator and (AL) (CU) rod

___ 600A apparatus bushing with (AL) (CU) rod

___ Automation accessories