SIRIUS 3RU2/3RB3 overload relays
5.5 Configuration
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
507
Ambient temperatures for 3RU21 overload relays
3RU21 thermal overload relays compensate temperature in the temperature range from –
40 °C to +60 °C according to IEC/EN 60947-4-1. At temperatures from +60 °C to +80 °C, the
upper set value of the setting range has to be reduced by a specific factor in accordance with
the table below.
Table 5- 11 Ambient temperature for 3RU21 overload relays
Reduction factor for the upper set value
Ambient temperature in °C
Current ranges
0.11 to 20 A
Current ranges 17 to 40
A
+60 1.0 1.0
+65 0.87 0.97
+70 0.94 0.94
+75 0.81 0.90
+80 0.73 0.86
Ambient temperatures for 3RB30/3RB31 overload relays
3RB30/3RB31 solid-state overload relays compensate temperature in the temperature range
from –25 °C to +60 °C according to IEC/EN 60947-4-1.
The reduction factors which have to be taken into account when using solid-state overload
relays at an ambient temperature higher than 60°C can be obtained on request from our
Technical Assistance on the Internet (http://www.siemens.com/automation/service&support
).
Derating during heavy-duty starting for 3RB30/3RB31 overload relays
There is no derating during heavy-duty starting in size S00 (up to 16 A).
The following derating has to be taken into account in size S0 (up to 40 A).
Table 5- 12 Derating during heavy-duty starting, 3RB30/3RB31 overload relays
CLASS Rated current
CLASS 20 I
e max
= 32 A
CLASS 30 I
e max
= 25 A
Special application environments
SIRIUS components have been approved by a whole range of bodies for various sectors
(shipbuilding, etc.). An up-to-date list of approvals appears in Chapter 20 of the Siemens
Low Voltage LV1 Catalog, and more information, as well as an option to download
certificates, can be obtained on the Internet
(http://www.siemens.com/automation/service&support
).
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