VAMP 150 - Page 59

VAMP Ltd
Motor protection relay
Technical Description
VAMP 150
VM150.EN005 Vamp 24h support phone : +358 (0)20 753 3264
31
T>trip
T>start
Alarm Trip
T1 A1
L
VAMP150
Outputmatrix
+
+
+
M
Open
coil
Close
coil
STOP START
1
Figure 3.1-1. Application where the T> start signal prevents starting of the
motor if the starting would cause heating over the trip limit Θ
TRIP
. The T>
start signal is active when the calculated temperature exceeds the setting
value Θ
ALARM
. The relay A1 is configured to be “normal closed”.
Qtrip
Qload
Qalarm
10%
10min 20min 30min 40min 50min 60min
20%
30%
40%
50%
60%
70%
80%
90%
100%
120%
TEMPERATURE
Q
TIME
1
2
3
4
5
10min 20min 30min 40min 50min 60min
TIME
1
10min 20min 30min 40min 50min 60min
2
3
4
5
CURRENT
(xImax)
TIME
Iload
Imax
Istart
Q
deadband
T>start
T>trip
VAMP150ThermalModelBehaviour
Figure 3.1-2. Example of modelled motor temperatures by the thermal
overload stage when current has been cut off enough long so that the motor
has cooled down. The temperature curve 5 describes an inhibited start
attempt.