insulators Flashcards
Conductors on overhead lines are electrically insulated from the ground by either resting on insulators or being ?
suspended from insulators
Three materials used for overhead line insulators are porcelain, polymer, and ?
glass
If three phases and a neutral are mounted on a crossarm, the neutral can be identified as it is the one mounted on a ? insulator.
glass
A combination of dirt and moisture will cause insulators to flash over; ? is/are also a likely cause.
lightning
The glaze on a porcelain insulator helps the insulator’s surface shed dirt and bead water.
true
Pin-type insulators can be two or more pieces cemented together.
true
A one-piece insulator can withstand a higher voltage than a two-piece insulator.
false
Hand wire ties or ? ties are used to fasten a conductor on most top tie insulators.
preformed
Each disk of a porcelain or glass suspension insulator is rated at ?
11 kv
A porcelain suspension insulator uses a ball-and-socket design which puts the insulating material under ? to create strength.
compression
One piece porcelain pin-type insulators are used on lines where the voltages are less than ?
23 kv
A polymer suspension insulator cannot withstand the tension of deadend conductors.
false
Pin insulators are no longer used on transmission lines.
true
If a suspension insulator string is made up of 50 kip insulators, the insulator string is able to withstand ? of tension.
50,000 lbs
Post insulators are positioned on a pole to support conductors in a vertical or horizontal ? position.
cantilevered