1MRS751802-MUM
REX 521
105
Protection Relay
Technical Reference Manual, Standard Configurations
7.1.15.
3I()
The function block 3I() is designed for the phase-reversal protection of motors
.
Fig. 7.1.15.-1
Function block symbol of 3I()
1
Includes the delay of the signal relay
2
Includes the delay of the heavy-duty output relay
Phase-reversal protection
Operation mode
Not in use
2-phase
3-phase
Operate time
0.1...10.00 s
Rotation direction
Forward
Reverse
Note! The values below apply when f/fn = 0.95...1.05:
Operation accuracies
Phase angle difference ±2°
Current ±0.01 x In
Start time
Start time when phase order is wrong
and the injected currents = 1.0 < In:
Internal time <72 ms
Total time <80 ms
1
Reset time
40...1000 ms (depending on the minimum pulse width
set for TRIP output)
Reset ratio
Reset value for phase angle difference: 3°
Retardation time
Total retardation time when correct phase order is
restored: <60 ms
2
Operate time accuracy
Depends on the frequency of the current measured:
f/fn = 0.95...1.05: ±2% of set value or ±20 ms
2
Frequency dependence of the settings and
operate times
(see above)
Suppression of harmonics:
-50 dB at f = n x fn, where n = 2, 3, 4, 5,...
BLOCK
GROUP
RES ET
S TART
TRIP
CBFP
3I()
Summary of Contents for REX 521
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