Ac Current - Siemens Argus 7SR21 Technical Manual

1.2.1.3 Operational Features
Attribute
0% Dip Withstand Period
Dip Immunity Acquisition Period
NOTE: -
Dips in supply that fall below the minimum voltage for a period greater than the 0% Dip Withstand Period, will
invoke a relay reset.
During conditions of auxiliary input voltage variations which are not described
may enter a safety protection mode where a power supply shutdown occurs. This condition is designed to
protect the power supply from damage as well as prevent internal relay faults from developing into dangerous
situations.
Once the relay has entered this safety mode, it may be necessary to reduce the auxiliary input voltage to zero
volts for up to 30 seconds before re-application of the auxiliary supply will cause the relay to power up and
operate normally.
(1) Using fuses as on/off switches or allowing batteries to run at very low cell voltages for extended periods and
then attempting to re-charge them are examples of such auxiliary supply conditions.
1.2.2

AC Current

Nominal
In 1 A, 5 A Phase and earth
fn 50 Hz, 60 Hz
Sample Rate
Note. 1 A and 5 A nominal inputs are user selectable on each model.
Unrestricted © 2013 Siemens Protection Devices Limited
Value
100 ms
5 minutes
Measuring Range
80 x In
47 Hz to 62 Hz
32 cycles / sec @ 50 Hz
7SR21 & 7SR22 Performance Specification
Comments
Typical time after switch on to
attain claimed immunity to dips
(1) in section 1.4.3.1, the relay
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