3.2.12 External CT Ratio
The CT ratio shall be set accordingly for the display to
show primary current. For example when using 150/5
CT, set the value to:
5
3.2.7 Phase Loss
Phase loss fault is detected when average motor current
is larger than 0.28 x I
B
but any phase current is less than
0.1 x I
B
. Tripping takes place in less than 120ms when
phase loss is detected.
3.2.8 Phase Sequence
Phase sequence fault is detected when the phase
sequence in any 2 or all the phases are reversed.
Tripping takes place in less than 120ms when phase
sequence fault is detected.
Phase loss and phase sequence protection can be
enabled and disabled separately. Refer to
3.2.16 Phase
sequence / phase loss option
3.2.9 Prolonged Starting and Stalled Rotor
For prolonged starting and stalled rotor there is one I
S
>>
setting and separate delay time setting for each
protection. I
S
>> shall be set below the motor starting/
stalled current. These protections are useful when
thermal overload protection is not fast enough to protect
the motor during stalling.
Delay time for prolonged starting, t
Start
>> shall be set
longer than specified motor starting time. Tripping takes
place when any phase current is larger than I
S
> for
longer than t
Start
during motor starting.
Delay time for stalled rotor, t
Stall
>> is activated upon
completing the motor starting. Tripping occurs when any
phase current is larger than I
S
>> for longer than t
Stall
>>
during motor running.
Both protections can be disabled by setting I
S
>> to 'off'.
To disable only one of the protection, set the respective
delay time for the protection to be disabled to much
longer than specified.
3.2.10 Earth Fault
Earth fault protection is based on zero sequence current
calculation. Tripping takes place when the current is
larger than earth fault setting in % of I
B
for longer than
t
0
>. It can be disabled by setting t
0
>> to 'off'.
3.2.11 Base Current
Base current is the motor full load current. The range of
setting is model dependent.
The formula is:
For example to use the relay with motor that has full load
current of 138A, using external CT of 150/5,
Motor full load current
I
B
= X
CT ratio
1
= 4.6A
I
B
=
X
= 30
3.2.13 Manual or Auto Reset
The relay can be set to manual or auto reset when the
relay trips. Resetting of relay is allowed when the tripping
condition cleared. Manual reset is performed by pressing
the "RESET/MODE" (or using binary input if it is
configured as 1 - Reset trip). Thermal overload is always
auto reset.
3.2.14 Binary Input
The binary input is a dry contact input that can be
configured to perform various functions.
0 - Block relay 1
The input, when triggered, will force relay 1 off.
1 - Reset tripping
The input is used to manually reset a tripping.
2 - Instant tripping
The input will generate a tripping condition. Refer to
4.4 Binary Input Tripping.
3.2.15 Relay 2
The relay 2 output can be configured to turn on in these
conditions:
0 - On any tripping
Relay 2 on during any tripping.
1 - On thermal tripping
Relay 2 on during thermal tripping only.
2 - On thermal warning
Relay 2 on when motor current is more than 1.05 x I
B
.
3.2.16 Phase sequence / phase loss option
Phase sequence and phase loss detection can be on
(enabled) and off (disabled) separately.
0 - Phase sequence and phase loss off
1 - Phase sequence on
2 - Phase loss on
3 - Phase sequence and phase loss on
3.2.17 Frequency
Nominal value of the network frequency. Select either 50
or 60 Hz.
External CT ratio =
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