Automatic Bypass Transfer Switch Maintenance Checklist
De-energized/Bypassed Checks
1. Record the automatic bypass transfer switch engine start signals voltage and de-energize/remove.
2. Verify and record all sensing and time delay functions in the automatic transfer switch.
3. Operate the bypass to normal or emergency power.
4. Isolate/de-energize the automatic transfer switch.
5. Remove the arc chutes and pole covers.
6. Vacuum clean the accumulated dust from the automatic transfer switch and accessory panels.
7. Inspect for moisture or signs of previous wetness or dripping.
8. Remove dirt and grime with an approved cleaner/solvents.
9. Clean and lubricate TS coil and operator linkage.
10. Inspect all insulating parts for cracks or discoloration due to excessive heat.
11. Inspect all main arcing contacts for excessive erosion.
12. Inspect all main current carrying contacts for pitting and discoloration due to excessive heat.
13. Perform contact resistance test on normal and emergency main contacts.
14. Inspect and test all auxiliary control contacts and relays for proper operation.
15. Inspect and clean all add-on panels and accessories.
16. Re-install arc chutes and pole covers.
17. Manually operate the automatic transfer switch to check proper contact alignment, deflection
gap and wiping action and control contact operation.
18. Check all cable and control wire connections to the transfer switch control and sensing panel
and other system components and tighten if necessary.
19. Re-energize the automatic transfer switch by placing the isolation to the connected position.
20. Please the bypass unit back into the connected position.
21. Reconnect engine start and verify proper control voltage.
22. Conduct a test by simulating a normal source failure.
23. Perform millivolt drop readings across normal and emergency main contacts during transfer
test.
24. Prepare computer generated report of inspection for each piece of equipment and submit
to customer.
Automatic Transfer Switch (Non-Bypass) Maintenance Checklist
Energized Checks
1. Record automatic transfer switch engine start signals voltage.
2. Verify and record all sensing and time delay functions in the automatic transfer switch.
3. Vacuum/clean any accumulated dust from the automatic transfer switch and accessory panels where it is safe to
do so.
4. Visually inspect for moisture or signs of previous wetness or dripping.
5. Remove dirt and grime with an approved cleaner/solvents where it is safe to do so.
6. Visually inspect the TS coil and operator linkage for proper lubrication.
7. Visually inspect all insulating parts for cracks or discoloration due to excessive heat.
8. Visually inspect all main current carrying contacts for discoloration due to excessive heat where it is safe to do so.
9. Visually inspect all add-on panels and accessories.
10. Visually inspect all cable and control wire connections to the transfer switch control and sensing panel
and other system components for proper connections.
11. Conduct a test by simulating a normal source failure.
12. Perform millivolt drop readings across normal and emergency main contacts during transfer
test.
13. Prepare computer generated report of inspection for each piece of equipment and submit
to customer.