Functions
2.11 Thermal Overload Protection (ANSI 49)
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
87
Emergency Start
The run-on time to be entered at address 1616 T EMERGENCY must be sufficient to ensure that after an emer-
gency startup and dropout of binary input „>Emer.Start O/L“ the trip command is blocked until the thermal
replica is again below the dropout threshold.
Ambient or Coolant Temperature
The specifications given up to now are sufficient for modeling the overtemperature. In addition to this, machine
protection can also process the ambient or coolant temperature. This must then be signaled to the device either
via the measuring transducer TD2 provided as a temperature-proportional DC current from a measuring trans-
ducer with a live zero signal between 4 and 20 mA, linked via the thermobox, or as a digitalized measured value
via the fieldbus (e.g. Profibus DP). Address 1607 TEMP. INPUT serves to select the temperature input pro-
cedure. If there is no coolant temperature detection, address 1607 is set to Disabled. The allocation between
the input signal and the temperature can be set at address 1608 (in °C) or 1609 (in °F) TEMP. SCAL.. The
temperature value set there is equivalent to 100 % of the Profibus DP/Modbus value, or full-scale deflection
(20 mA) of the measuring transducer. In the default setting, 100 % (field bus) or 20 mA (measuring transducer
TD2) corresponds to 100 °C.
If under address 1607 TEMP. INPUT the temperature setting of RTD 1 is selected, the scaling under ad-
dress1608 or 1609 is ineffective. The works setting can be left as it is.
If the ambient temperature detection is used, the user must be aware that the K-FACTOR to be set refers to an
ambient temperature of 40 °C, i.e. it corresponds to the maximum permissible current at a temperature of 40 °C.
As all calculations are performed with standardized quantities, the ambient temperature must be standardized,
too. The temperature at nominal machine current is used as standardization value. If the nominal machine
current deviates from the nominal CT current, the temperature must be adapted according to the following for-
mula. At address 1605 or 1606 TEMP. RISE I the temperature adapted to the nominal transformer current
is set. This setting value is used as standardization quantity of the ambient temperature input.
with
Θ
Nsec
Machine Temperature with Secondary Nominal Current = Setting at the 7UM62 (address
1605 or 1606)
Θ
NMach
Machine Temperature with Nominal Machine Current
I
Nprim
Primary nominal current of the current transformer
I
NMach
Nominal current of the machine
If the temperature input is not used, the address 1607 TEMP. INPUT must be set to Disabled. In this case,
the settings of the addresses1605 or 1606 and 1608 or 1609 are not considered.
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