TR A N S FOR M E R BUS H I NG S T YPE G S B 8 0 0
I N S TA L L AT I O N A N D M A I N T EN A N C E G U I D E
21
Do not
wire brush inner contact surfaces on
aluminum outer terminal studs!
M8 screws, with conical
spring washers and flat
washers (20 ±2 Nm)
M10 screws, with flat
washers (40 ±2 Nm)
Gasket
Tightening
ring
The outer terminal stud
2.12 Mounting of outer terminal
Before connecting conductor clamps, the outer
terminal studs must be carefully wire brushed and
greased with a contact compound or vaseline. The
inner contact surfaces on the aluminum outer
terminal studs are tin-zinc plated, and
may not
be
wire brushed; see Fig. 28.
In order to obtain the correct pressure and low contact
resistance, the outer terminal must be removed and refitted
as follows:
1. Remove the outer terminal and inspect the contact
surface of the outer terminal and the conductor tube.
2. Carefully clean the contact and gasket surfaces.
3. Lubricate the gasket with Mobilgrease 28.
4. Assemble the tightening ring, the gasket and the outer
terminal stud and push them over the conductor tube.
Make sure that the tightening ring is mounted with the
gasket track towards the gasket. An extra gasket is
supplied with the bushing and intended for final
installation.
5. Grease all bolt threads and surfaces beneath the bolt
heads with Molykote Multilub or other suitable
compound.
6. Insert the M10 screws with flat washers, which press the
stud against the conductor tube and the upper draw-rod.
Tighten in steps to a final torque of 40 ±4 Nm.
7. Insert the M8 screws with conical spring washers and
flat washers that hold the tightening ring. Tighten them
to press the gasket into place. Tighten in steps to a final
torque of 20 ±2 Nm.
It is extremely important in both cases to tighten
evenly. Gradually tighten the bolts, working in a
crosswise pattern.
—
28 Outer terminal.
