Maintenance

All switch components, including insulators and blade assemblies must be cleaned as follows:

• Every year or after 1000 operations

• Wipe the dust from the components with a clean dry cloth. After cleaning, apply a light coat of non-corrosive high-temperature grease that will not harden upon exposure to air (SHC-32 Mobiltemp or equivalent) to all contact surfaces.

Check the blades and ensure that they are making good contact.

• Take a contact resistance measurement between (1) the jaw and spade terminal and (2) the hinge spade terminals. It should read between 38 to 100 micro-ohms for a new, unused switch.

• Ensure that the blades can be "opened" from the jaw casting with a pulling force of 30–36 pounds measured at a point between the main blades, just below the jaw contact.

• Wipe and clean the contacts, especially if the switch has not been in operation for a while. Open and close the switch several times in succession to do so.

CAUTION
Switch blade contact Damage Do not clean the blades with abrasive materials or abrasive cleaners. Failure to follow these instructions can result in injury or equipment damage.

Keep all insulator surfaces clean, particularly when the switches are in harsh environmental conditions. Clean the insulators with a clean lint-free cloth dampened with either denatured alcohol or isopropyl alcohol.

Carefully inspect all insulators for signs of carbon tracking. Focus on areas where the conductor passes through an insulator or are near a barrier. Examine the surface for cracks or discoloration. Contact your Schneider Electric field sales representative if any of these conditions exist.

Inspect the bus and connections for evidence of overheating or damage.

• Using an appropriate insulation tester or Megger™, measure and record the resistance to ground, and the resistance between phases of the bus and connections insulation.

• Measure and record the ambient temperature and humidity.

Analyze these readings over consecutive periods to identify trends indicating insulation degradation.

The operating shaft connects the stored energy mechanism to the switch operating arm. Lightly coat the shaft bearings, door interlocks, and door latch surfaces with lubricant (white lithium grease).

Each main blade in the switch is connected to the main operating shaft by an insulating pushrod. Check the pushrods for signs of damage to either end each time a normal maintenance inspection is performed.

The stored energy mechanism consists of a housing with a one-piece crank sprocket assembly supported by bearings and a spring assembly. The sprocket assembly is chain-driven using the operating handle on the front of the enclosure. As the handle is moved upward, the spring assembly is charged. As the crank sprocket assembly passes over the center position, the spring takes control and drives the switch to the closed position.

The moving parts are the front and rear latches, which are spring-operated, and the two shaft bearings. Check the moving parts after approximately 100 operations to make sure the latches rotate freely up and down using finger pressure on the rollers. Check for loose bearing bolts.

Mechanical (non-electrical contacts): Clean and lubricate the bearing points and sliding surfaces at regular intervals with a thin film of white lithium grease. Before lubrication, remove any hardened grease and dirt from the latch and bearing surfaces with a clean, dry lint-free cloth.

Disconnector switch contacts: Clean and grease the contact surface of the movable blades and the stationary contact surfaces with SCH-32 Mobiltemp, or equivalent.

Perform a one minute high potential test on the primary circuit, busing and interrupter switch, at a field test value of either 14 kV AC or 20 kV DC.

The following tables list the inspection checks that are necessary to maintain and to verify that the equipment remains operational.