Replacement Of Damper Assembly; Replacement Of Spring Charging Motor (Device 88); Replacement Of Vacuum Interrupters; Index Of Figures And Tables - Siemens SDV-4A Instruction Manual

Overhaul
Replacement of Enindine Damper Assembly (see Figure
26) - Damper replacement will require the removal of a pin
which ties the damper mounting yoke to the circuit breaker
operator frame. Refer to Figure 35a.
The damper is attached to the mounting yoke with a lock
washer and 5/8-18 jam nut. For added security, the jam
nut is treated with a thread locking adhesive (Loctite 271
with Loctite type T primer), and then torqued to a value of
17-20 ft-lbs.
Check all associated parts, damper body and telescoping
tube, for wear. Replace as necessary.
The telescoping tube and internal striker block employ slugs
in variable thicknesses and quantity to control movable
contact motion. If the telescoping tube is replaced, the tube
must be replaced with the correct tube to assure that the
correct type and number of slugs are present.
Figure 35a.
Replacement of Spring Charging Motor (Device 88) - Re-
move the quick-disconnect terminals. Then remove the
screws holding the motor mounting bracket to the breaker
housing. The motor slips out as a complete assembly.
Check and replace as required.

Replacement of Vacuum Interrupters

The following procedures are for the removal and replace-
ment of the vacuum interrupters.
Figure 35b.
Replacement of Liner Decelerator (shock absorber) (see
Figure 26) - For replacement of this type of shoch absorber,
refer to Figure 35b and implement the following steps:
Loosen the jam nut on the body of the shock absorber and
remove the retaining rings from the ends of the pin located
below the shock absorber. Remove the pin — capture the
spacers and washers. Remove the shock absorber, jam
nut, star washer and adapter from the shock absorber tube.
(Note — the spacer which is trapped between the shock
absorber and the adapter should be kept with the adapter).
Set the new shock absorber setting to Position 8. tighten
the set screw to 6 in. lbs. Thread the jam nut on to the
shock absorber body, install star washer and thread the
body of the shock absorber into the adapter. Continue to
thread in until the shock absorber bottoms out on the spacer
inside the adapter. Place the body of the shock absorber
into the tube and fit the adapter into the breaker channel.
Align holes, add spacers and washers to center the shock
absorber and the tube, and secure with pin and retaining
ring. Tighten the jam nut.

Recommended Hand Tools

Type SDV circuit breakers use both standard American and
metric fasteners. Metric fasteners are used for the vacuum
interrupters. American fasteners are used in all other loca-
tions. This list of hand tools describes those normally used
in disassembly and re-assembly procedures.
Note: Special care needs to be exercised in removal
of hardware around the movable contact end of the
vacuum interrupter.
The movable contact uses a metal bellows assembly
to maintain the vacuum seal while still permitting in
and out motion of the contact. This bellows assem-
bly is rugged and reliable, and is designed to with-
stand years of horizontal movement. However, care
should be exercised in subjecting the bellows to ex-
cessive torque during removal and replacement.
Twisting the bellows through careless bolt removal
or tightening may damage the vacuum interrupter.

Index of Figures and Tables

Vacuum Tube Voltage and
Family Continuous Current
Pole Unit Assembly
VS17006 15.5kV, 1200 Amp
VS25008 15.5kV, 2000 Amp
VS25008 25.8kV, 1200 and 2000 Amp
Breaker Side Elevation (Typical)
Tube Clamp Fastening
Procedure / Stroke Adjustment
Reference Tables and Lists
Fastener Torque Limits
Figure
37
38
39
36
40
Table 7
34