Siemens 21-115532-001 manual Periodic Inspection

MAINTENANCE

Page 12

	When inspecting, check to be certain all hardware and con-
PERIODIC INSPECTION
	nections are tight. The principal point of the internal inspection will
	be the condition of the arcing contacts on the tapchanger. Since
A sample of oil from the regulator should be subjected to	numerous factors influence the rate of contact tip wear, no one
	criteria can be stated to recommend when a contact should be
dielectric breakdown test, per ASTM D-877. If found below
	changed.
25kV, the oil should be changed or reconditioned. Refer to
ANSI C57.106-2002. Other tests, especially Neutralization	The following figure shows the possible condition of contact wear
Number, Interfacial Tension and Power Factor are also useful
	after a period of operation. If the contact surface is less than 1/8
and may be preferred by particular users.
	inch wide, the contact should be replaced. (See the Figure below)
The oxidation inhibitor in the oil will be depleted over a period	Contacts, both movable and stationary, show normal burning and wear
of a few years and should be replaced. The inhibitor is 2, 6-
ditertiary-butyl-para-cresol (DBPC) at a concentration level of	once placed in service. If for any reason A1 dimensions exceed 4/5 of
0.2 to 0.3%.	A, the stationary contact should be replaced. (See the Figure below)

The time interval between internal inspections will depend upon frequency of tapchanger operation and the load on the regulator. Regulators subjected to numerous overloads and a high load factor may require more frequent inspections than those carrying normal loads. While internal inspection is not a necessity, preventive maintenance inspections will help assure the continuity of service.

To untank a JFR regulator, proceed as folllows:

1.Remove the regulator from service as described on Page10.

Hazardous voltages. Will cause serious injury, death, or equipment damage.

To prevent:

Always de-energize and ground the equipment before maintenance requiring access to high voltage parts.

A

A1

•UPPER FILTER PRESS SEALING

If cover top cap is removed, make certain the cap is properly sealed when replaced on cover. Siemens recommends applying pipe sealant (Loctite PST or equivalent) around the threads of the adapter. Furthermore, it is recommended that the seal be tested by applying 5 psig pressure through the pressure relief valve fitting for 5 minutes, with no loss in pressure. Failure to assure seal may allow moisture to be pulled into the unit during a cool-down cycle.

2.Place the regulator in a position where energized overhead lines will not interfere.

3.Operate pressure relief valve to vent regulator before un- tanking

4.Remove the mounting bolts holding the control box onto the main tank.

5.Remove all cover bolts.

6.The regulator can now be pulled from the main tank by the cover lifting eyes.

•FAN MAINTENANCE

Cooling fans (if equipped), require minimum attention. Fans with plain sleeve bearings or Oil-Litesleeve bearings should be oiled at least once a year with SAE 10-W engine oil which does not thicken in cold weather. Oil must be added to sleeve bearings before starting motor for the first time after installation.

Fans equipped with ball bearing motors are packed with grease before shipment and should be greased at least once a year with a soda-soap, ball-bearing grease of medium consistency furnished by a reliable supplier.