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Stalled motor protection
2.28.5
The stalled motor protection determines whether the motor is staying at stalled condition
during the condition, when the motor status is being start-up or running. The stalled motor
protection can issue a trip signal, when overcurrent relay (Mot-Stall-OC) operates and the
stalled motor protection receives a speed switch signal from the tachometer. The Mot-Stall
function operates when On is set for the setting [Mot-Stall-EN].
Element of motor-stall overcurrent relay (Mot-Stall-OC)
The stalled motor protection has an overcurrent element to observe motor current. This
OC element operates when the motor current is larger than the pick-up value, which
the user can set with setting [Mot-Stall-OC].
Figure 2.28-10 Relay characteristic of Mot-Stall-OC
Scheme logic
The scheme logic of the stalled motor protection is illustrated in Figure 2.28-11
8000211C23
Mot-Stall-OC
800000EBB0
Mot-Stall_SpSW
830000EBB5
Mot-Stall_BLOCK
Mot-Stall-EN
MotSt-Irreg-Op
Figure 2.28-11 Scheme logic of the stalled motor protection
A speed switch signal which is generated when motor speed is decreasing is received from the
tachometer via the binary input circuit (BI) and connected to the PLC connection point [Mot-
Stall_SpSW].
The stalled motor protection can be blocked when a signal is generated at PLC connection point
[Mot-Stall_BLOCK].
0
&
1
On
- 330 -
Setting[Mot-Stall-OC]
Motor current
8000001B70
T-Mot-Stall
t 0
0.00-300.00s
6F2T0207 (0.01)
Mot-STALL-TRIP
GRE200 (5,6)
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