Operating instructions for POLIM
©
R surge arrester
ABB
6
EN
Doc. 1HC0075743 AA
3.
DESCRIPTION
3.1.
Intended use
The POLIM
®
-R is a surge arrester intended for use in low- and medium-voltage
applications. Surge arresters protect the insulation of devices against unaccept-
able overvoltages which are caused by lightning or switching operations.
The manufacturer is not liable for resulting damages from further, unintended use.
The operator accepts all responsibility for using the POLIM
®
-R outside of its in-
tended application range as specified in this document.
3.2.
Structure and function
The POLIM
®
-R.. -1 surge arrester is constructed from one or more in series con-
nected non-linear metal-oxide (MO) resistors. The POLIM
®
-R.. -2 surge arrester is
constructed from parallel connected non-linear metal-oxide (MO) resistors. These
MO resistors have an extremely non-linear resistance property. At the maximum
operating voltage of U
c
, only a small capacitive current will flow in the mA range.
With an increase in voltage, the MO resistors enter a highly-conductive state prac-
tically without delay. Thus any further increase in voltage is limited to the specified
residual voltage values. After the decline of the overvoltage the arrester immedi-
ately turns back to the non- or slightly-conductive state. The MO arrester converts
the energy of the surge into heat, which it transfers to the surrounding air.
The MO resistors or stacks of them are connected with the ground plate and top
termination. The directly molded silicone housing protects it from all environmental
and weather influences. This design has proven to be the best solution in every
environment for years.
Thanks to its high and very high energy absorbing capability the POLIM
®
-R is es-
pecially suited for overvoltage protection of:
transformers, cables, capacitors
generators
machines
locomotives and other apparatuses in railway applications
other low- and medium-voltage apparatuses and systems
Variants of the surge arrester POLIM
®
-R suitable for the use in d.c. systems are
also available. They differ from POLIM
®
-R surge arresters for a.c. systems by the
appendix
D
as second letter in the complete term of classification
(e.g. POLIM
®
-R 0.44-1 N
D
).