35
PowerVac
®
5kV Vertical Lift
Chapter 11. Mechanical Adjustments
11-1 General
The ML-19 VL Mechanism has been designed
for extended intervals between maintenance. In
most cases only the wipe and gap adjustments
will require re-setting throughout the life of the
circuit breaker.
11-2 Wipe Adjustment
Wipe is the additional compression of a pre-
loaded spring, used to apply force to the vacuum
interrupter contacts and to provide opening kick-
off force. Always adjust the contact wipe before
adjusting the gap.
An indicator is provided on the wipe spring as-
sembly with graduations given in 0.032 inch on
which the wipe is indicated directly. Reference
Figure 29.
Figure 29. Wipe Insulator
1
Wipe Spring
2
Wipe Plate
3
Wipe Indicator
4
Locknut
5
Operating Rod
6
Coupling Clamp
7
Coupling Clamp Screws
Improved accuracy of wipe measurement may
be obtained by using a feeler gauge between
the top of the wipe spring (5/8) nut and bottom
of the spring block. The difference in readings
on each pole with the breaker closed and open
is the contact wipe. Adjustment is not required
if the wipe is more than 0.075 inch. After adjust-
ment the wipe should be 0.15-0.18 inch.
To adjust the primary contact wipe, close the
breaker and proceed as follows:
1.
Loosen, but do not remove, the two cap
screws (Figure 29, Item 7) holding the in-
terrupter clamp.
2.
Check that the interrupter clamp is loose.
A light prying at the clamp half junction
may be required to loosen the wedging ac-
tion of the clamp.
3.
Hold the hexagon projection (Figure 29,
Item 4) at the bottom of the operating rod
insulator (1 inch wrench) and loosen the
adjacent locknut (Figure 29, Item 4), with
(3/4 inch wrench). Adjust by rotating the
operating rod insulator. The thread is 1/2-
13 and each turn will give about 0.078 inch
change in primary wipe. Screw the oper-
ating rod insulator toward the interrupter
to increase wipe.
4.
After setting the contact wipe on each
phase, torque the operating rod locknut
(Figure 28, Item 5) to 40-50 foot pounds
while holding the hex projection (8) to pre-
vent the operating rod insulator (5) from
turning. Tighten the clamp screws (7) to 8-
10 foot pounds and trip the breaker open.
This procedure prevents accidental twist-
ing of the interrupter’s operating rod by load-
ing the contacts with the wipe springs and
forcing relative rotation to occur at the
clamp interface. After adjustment, re-mea-
sure the wipe dimensions (Figure 25). If
the wipe settings are within the required
limits, this indicates there is an adequate
contact closing relationship between the
poles.
1
2
3
4
5
6
7
