Areva MiCOM P225, Technical Manual

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P225/EN FT/B11 User Guide
Page 26/52 MiCOM P225
4.10.8 The [51LR/50S] BLOCK ROTOR submenu
4.10.8.1 Rotor stalled whilst the motor running
This function, which makes it possible to detect stalling while the motor is running, is
activated immediately after the starting period, that is on expiry of the starting time delay t
I
start
(submenu 4.10.7 [48] EXCES LONG START).
Two parameters can be set: the stalled rotor current threshold
I
stall
with its associated time
delay t
I
stall
, the stalled rotor time.
The MiCOM P225 relay detects the overcurrent caused by stalling and generates information
that the rotor has stalled while the motor is running if the phase current exceeds the
threshold
I
stall
for a length of time greater than t
I
stall
.
I
stall
>
tI
stall
0
I
A
I
B
I
C
Internal
logic
signals
&
Successful
start signal
Re-
acceleration
in progress
>=1
Motor
starting
criterion :
52A+I
Motor start-
up non
detected
&
Motor
shutdown
( EL1 = 0 )
tI
stall
0
>=1
P0196ENa
N.B.: – During authorisation of re-acceleration (AUTOMAT. CTRL menu),
this function is deactivated during the time delay allowed for
starting
t
I
start
.
– On starting the motor, when the start detection criterion selected is
"closure of the contactor/circuit breaker and exceeding of the
starting current threshold
I
start
(52 a +
I
)", if the relay sees only one
of these events, (closure of the breaking device or the appearance
of a current greater than
I
start
), then the function of monitoring a
stalled rotor whilst the motor is running is activated.