Stall Setting
Starting Current
Current
0
Due to trip
Time
Time
Start Successful
0
1
t
0
t
1
At the time t1 when the timer is
timed out and the voltage has
remained below Low V Set, the
relay trips on “Stall Prol. Start”.
Time
Low V Detection
0
1
Reac. Time
Reac. Time timer
starts when low
voltage condition is
detected. During
this period Stall
function is disabled .
Time
1
0
High V Detection
Reac. Long Time
t
2
At the time t
2
when the timer
is timed out and the voltage
has remained below High V
Set, Auto Re-Start is disabled.
P4964ENa
Figure 78: Automatic restart failed- voltage restored after the set time
If v
oltage is not restored within Reac. Long Time duration or if it falls below “High V Set” threshold before Reac.
Shed Time timer has timed out (where Reac. Shed Time timer is set to a value other than zero for sequence start
scheme), Auto Re-Start KO becomes asserted. For default LED and Output Relay management refer to the default
PSL.
14.8 APPLICATION NOTES
14.8.1 START/STALL PROTECTION
When a motor starts it draws a value of current in excess of full load rating for a set period of time, namely the
star
ting time. It is normal practice to assume a constant starting current for the whole of the starting time.
The starting current varies depending on the type and method of starting utilized. If the motor is started direct-on-
line (DOL), the current could easily reach 6 times full load current. However, when star/delta starting is utilized, the
starting current is Ö3 less than when DOL starting.
Chapter 6 - Current Protection Functions P24xM
154 P24xM-TM-EN-2.1
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