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IB140036EN
Instruction Booklet
Page
24
Effective: October 2014
O&M Manual for 40-1200A (480/600 Vac) ATC-900 3-Position,
Open/Closed Transition Contactor Based Transfer Switch
Section 8: Maintenance
8.1 Introduction
WARNING
HIGH VOLTAGES ARE PRESENT IN AND AROUND ATS EQUIPMENT.
BEFORE INSPECTING OR MAINTAINING THIS EQUIPMENT, DISCON-
NECT THE LINE POWER FROM, THEN LOCK OUT, IF POSSIBLE, THE
NEXT HIGHEST DISCONNECT DEVICE. FAILURE TO FOLLOW THIS
PROCEDURE COULD CAUSE SEVERE PERSONAL INJURY AND/OR
DEATH.
In general, ATS switch equipment is designed to be relatively
maintenance free under normal usage. However, because of the
variability of application conditions and the importance placed on
dependable operation by this type of equipment, inspection and
maintenance checks should be made on a regularly scheduled
basis. Since equipment maintenance will consist mainly of keep-
ing the equipment clean, the frequency of maintenance will
depend to a large extent on the cleanliness of the equipment’s
surroundings. If a significant amount of dust or foreign matter is
present, a more frequent maintenance schedule should be fol-
lowed.
It is suggested that visual inspections of the equipment be made
on a regular basis, not just during scheduled periods. Always be
alert for an accumulation of dirt in and around the structure; loose
parts; and/or hardware, cracks, and/or discoloration to insulation;
and damaged or discolored components.
8.2 Procedures
A suggested maintenance procedure is outlined in Table 5.
Table 5. Periodic Maintenance Procedures
STEP
ACTION
a. Make the ATS equipment safe for inspection and/or maintenance.
Disconnect the line power from equipment being serviced by opening the next highest disconnect device. Make
certain that any accessory control power is switched off by disconnecting all control plugs.
b. Inspect the structure area for safety hazards or potential maintenance problems. Inspect the area, especially where switching device is installed, for any safety hazards, including personnel
safety and fire hazards. Exposure to certain chemical vapors can cause deterioration of electrical connections.
Inspect for accumulated dirt, loose hardware, or physical damage.
Examine the primary insulation for evidence of cracking or overheating. Overheating will show as discoloration,
melting, or blistering of conductor insulation, or as pitting or melting of conductor surfaces due to arcing.
Inspect the secondary control connections for damage and the control wiring for insulation integrity.
c. Inspect the power contactor for dust, dirt, soot, grease, moisture, or corrosion.
Remove dust, dirt, soot, grease, moisture, and corrosion contamination from the surface of the switching device
using a dry soft lint-free cloth, dry soft bristle brush, and vacuum cleaner. Do not blow debris into the power
contactor. If contamination is found, look for the source and fix the problem.
d. Check for material integrity, uneven wear, discoloration, or loose hardware.
Severe material cracking will require replacement and loose hardware will need to be tightened.
e. Check the terminals and connectors for looseness or signs of overheating.
Overheating will show as discoloration, melting, or blistering of the conductor insulation.
Connections that do not have signs of looseness or overheating should not be disturbed.
f. Contact Inspection Procedure
Remove all the screws on the molded cover over the power assembly. Inspect the contacts. Contact Eaton if the
contacts have excessive wear. Reinstall the molded cover and tighten screws to 17 in-lbs.
g. Exercise the power contactor if it is not often exercised while in operation.
This will permit a “wiping” action by the contacts.
If the power contactor is used for frequent switching during normal operation, this step can be disregarded.
h. Return the ATS equipment to service.
Make certain all barriers are in place and doors closed. Reapply secondary and primary power.
