1ZSE 5492-118 en, Rev. 4
9
fm_00001
1 Introduction
1. Introduction
The delivery consists of on-load tap-changer, motor-drive mechanism and drive shaft sys-
tem.
The on-load tap-changer may be specified for cover-mounting or for yoke-mounting.
Cover-mounting means that the on-load tap-changer is lowered through a hole in the trans-
former cover and then bolted straight onto the transformer cover.
Yoke-mounting means that the on-load tap-changer is temporarily put onto a fork located
on the active part of the transformer. Yoke-mounting allows the transformer manufacturer
to connect the windings to the on-load tap-changer before drying and without having the
transformer cover mounted. The transformer cover is then lowered onto the tank, and the
on-load tap-changer is lifted and bolted to the cover. Please use the appropriate instruction
for cover-mounting or yoke-mounting!
The motor-drive mechanism and bevel gear are fitted to the transformer tank and the drive
shafts are fitted to complete the assembly of motor-drive mechanism, bevel gear and on-
load tap-changer before oil filling and testing.
The general arrangement of an on-load tap-changer system is shown in Fig. 1.
The general arrangement of an on-load tap-changer type UBB is shown in Fig. 2.
On-load
tap-changer
(SS)
Fig. 1. On-load tap-changer system.
Bevel gear
(SA21)
Vertical drive shaft
and protection covers
(SA)
Bevel gear
Horizontal drive shaft and
protection covers (SA)
Motor-drive
mechanism
Hand crank