Tech Info: Isolators Installation & Maintenance
On receipt of equipment compare components against the following checklist. Notify supplier immediately of shortages or damage.
1. Complete isolator per page 2: three phases per unit.
2. Interphase coupling tube – 38mm square tube: 1 length.
3. Vertical operating rods: 20mm bore pipe x 2m lengths: 3 lengths.
4. Operating lever assembly.
5. Operating rod insulating insert
6. Reciprocating operating handle assembly.
7. Flexible earthing strap.
NOTE: In cases where arc chutes have been removed for transportation, refit one to each
Phase as described on page 5 of this pamphlet.
INSTALLATION
Each isolator is factory aligned before dispatch, but to ensure years of trouble free operation, follow these instructions carefully: –
1. Place individual phases in position on the mounting framework. In the case of 11kV and 22kV isolators, ensure that the isolator pole fitted with adjustable hinge stops is mounted in the center phase position. This is important as the open and closed positions for all three phases are set by this phase.
2. Holding down bolts can be inserted, but not secured.
3. Loosen U-bolts on center hinge assemblies on each phase – removal is not necessary.
4. Position interphase coupling tube through square apertures in hinges, ensuring alignment with operating handle position and/or equal overlap through outer phase hinges.
5. Tighten U-bolts finger tight.
6. Open isolator, i.e. separate the main moving contact and the fixed contacts by pulling upwards on the main contact blade. All three contacts will open.
7. Close slowly, letting the moving contacts rest in the fixed contacts. Do not close completely.
8. Leaving the phase coupling tube free, align the three phase bases, and tighten the holding down bolts.
9. Tighten U-bolts on all phases.
10. Close isolator until the center phase moving contact is parallel to the base. Adjust the appropriate stop if necessary. Lock in position. At this point, ensure that the interrupter moving contact (Load break head, item 4) is not making contact with the arc chute internal contacts. It should not be necessary to adjust the open position stop.
11. Open the isolator slowly, checking that the arcing moving contacts have properly latched below the arc chute contacts, and remain below them until the main moving contacts are well clear of their fixed contacts.
12. Close the isolator slowly, checking that the arcing contacts on all phases latch below the arc chute contacts and once fully closed, do not touch them or the bottom of the arc chute. This setting is made by means of the eccentric stop.
13. Clamp the operating lever in the desired position on the phase coupling tube.
14. Place the operating mechanism handle in position, screw up bolts finger tight.
15. Fit rod guide in position on the structure
16. Attach one length of vertical operating pipe to the operating mechanism turnbuckle. Fit insulating insert (if supplied) to operating pipe.
17. Close operating mechanism.
18. Fit remaining operating rods, cutting top section to suit if necessary, Use pipe sockets and U-bolts on operating lever to secure.
19. Align operating mechanism handle and tighten fixing bolts.
20. With isolator in closed position and operating handle in the “ON” position, check that the center hinge is against the closed stop.
21. Tighten the operating mechanism turnbuckle until the operating pipe is taut. Secure in position with lock nuts.
22. Check all fasteners for tightness.
23. By means of operating mechanism, open and close the isolator a number of times to ensure a positive action exists.
24. Secure the operating mechanism earthing strap to the mechanism mounting base.
25. Secure incoming and outgoing conductors as required.