There are three basic solutions for cradles to meet the various insulator maintenance and replacement requirements. All of them are manufactured with Ritzglas® poles and enable works on cold end or suspension strings from 110 kV through 800 kV.

- Single insulator Cradles

Mostly used on insulator strings from 110 kV through 230 kV. They are supported by a pair of wire tongs or strain link sticks.

- EHV through design insulator Cradles

This cradle is designed to be used on 345 kV through 500 kV combined with cradles supports, providing the displacement of the insulators.

- EHV Side-opening insulator cradles

Used on cold end strings up to 800 kV to provide the removal of single or multiple insulator strings.

Single Insulator Cradles

This cradle is used either for change of insulators on the string or to assist in removing the string and lowering it to the ground. On deadened or running corners, these cradles are used in conjunction with strain carriers. On “I” suspensions, they are used with link sticks and adjustable strain pole assemblies.

They are manufactured with diameter 38 mm (1.5") Ritzglas® poles. Transmission cradles are provided with two steel lugs on the forward end, to support the insulator string with one pair of wire tongs or strain link sticks.

The back end of the cradle is provided with eyes and ropes to tie it up to the structure as hinging points. This way, the string may be raised or lowered to the most suitable position enabling the replacement of the damaged insulator(s). When lowering the insulator cradle is not necessary, the cradle is supported in eyes located on the forward yoke of Two-pole Strain Carriers.

TRANSMISSION INSULATOR CRADLES

EHV through design insulator Cradles

This equipment is used for insulator replacement on strings up to 500 kV. It is required when lowering a “V”-type or cold end insulator string and for raising “I”-type suspension insulator strings.

The deep through design is a safe feature to prevent accidental dropping of the insulator strings with the assistance of the Slotted Insulator Retaining Plate to secure the top insulator, keeping it firm during displacement.

The cradle can be lowered or lifted easily for insulators replacement, using the forged steel butt-swivels on one side and the steel bail (R070184) on the other, connected to a strain link stick. They are also provided with an auxiliary hook (R068922).

The steel bail and hook are supplied together with the cradle.

EHV THOUGH DESIGN INSULATOR CRADLES

Cradle Support

Manufactured with diam. 64 mm (2.5") Ritzglas® poles on its main structure. It is provided with a heat treated aluminum head, forged steel butt-swivel and three pairs of hooks attached to a spiral link stick, used as a support element.

CRADLE SUPPORT

EHV Side-opening insulator cradles

The side opening cradles have been designed for selective removal of an insulator string, particularly in double, triple or quadruple cold end bundles. Using this cradle, there is no need of removing top strings to get to the bottom string.

Manufactured with diam. 64 mm (2.5") Ritzglas® poles as its main element and three diam. 38 mm (1.5") poles, it is rated at 227 daN (500 lb) maximum work load, for the 2.69 m (8.8 ft) model and 454 daN (1000 lb) for the 3.91 m (13 ft) and 4.83 m (16 ft) cradles.

Butt-swivels on ends of poles rotate freely.

The 0.38 m (1.25 ft) hook assembly is used for single or double cold end bundles, whereas the 0.79 m (2.6 ft) assembly is used for the removal of bottom strings in quadruple cold end bundles.

The Insulator Retaining Plate has a dual purpose, one side is adaptable to diam. 279 mm (10") insulator bells and the opposite side is adaptable to diam. 324 mm (13") insulator bells.  

Sticks for connection to the boom, 01 pc of top insulator retaining plate, hook assembly and metallic brackets are supplied together with the cradles.

EHV SIDE-OPENING INSULATOR CRADLES