Configuration
6.5 Application environment
SIRIUS Innovations - SIRIUS 3RU2 thermal overload relays / SIRIUS 3RB3 solid-state overload relays
Manual, 09/2014, A5E03656507420A/RS-AA/002
57
6.5
Application environment
The following information must be taken into account when planning applications involving
overload relays.
Installation altitude
The overload relays are approved for installation altitudes up to 2,000 m. The reduced air
density at altitudes higher than 2,000 meters affects the overload relays' electrical
characteristics. The reduction factors which have to be taken into account when using
overload relays at altitudes higher than 2,000 m can be obtained on request from our
Technical Assistance on the Internet (
http://www.siemens.com/automation/service&support
Operating conditions and resistance to extreme climates
The overload relays are climate-proof.
The overload relays are not sensitive to external influences such as shocks, corrosive
ambient conditions, ageing, and temperature fluctuations.
Ambient temperatures for 3RU21 overload relays
3RU21 thermal overload relays compensate temperature within the temperature range –
40 °C to +60 °C in accordance with IEC/EN 60947-4-1. At temperatures between
+60 °C and +70 °C, the maximum permissible operating current related to the rated
operating current must be reduced by a specific factor f in accordance with the table below
(I
max
= I
e
x f).
Table 6- 5
Ambient temperatures for 3RU21 overload relays (size S00/S0)
Ambient temperature in °C
Reduction factor applies for ...
Rated current
0.16 ... 20 A
Rated current 22 ... 40
A
+60
1,0
1,0
+65
0,94
0,97
+70
0,87
0,94
Table 6- 6
Ambient temperatures for 3RU2136 overload relays (size S2)
Ambient temperature in °C
Reduction factor applies for ...
Rated current 8 ... 45 A Rated current 50 ... 80
A
+60
1,0
1,0
+65
0,94
0,97
+70
0,87
0,94
