VAMP Ltd
Overcurrent and earth-fault relay
Technical Description
VAMP 130
VM130.EN003
Vamp 24h support phone : +358 (0)40 573 6316
17
The heating time constant (
W
) and the load current factor (k)
corresponding to the maximum thermal load are adjustable.
Factor k defines the load current value, which, when exceeded,
results in a thermal trip.
The cooling time constant of the thermal overload protection is
the same as the heating time constant.
The thermal overload stage is provided with a separately
adjustable alarm function, the setting range of which is 60...99%
of the thermal trip level.
Figure 2.2.5-1 Principle of thermal overload protection.
Parameters of the thermal overload protection:
T> (49)
Parameter:
Value/unit:
Measured
value
Temp
%
Calculated thermal load (100%
= tripping)
T>
A
Permitted max. cont. current
primary value
T>
x In
Perm. max. cont. current as
compared to In
Alarm
%
Start level set value
Setting
values
tau (
W
)
min
Heating time constant
Fixed value
tau2 (
W
)
x In
Cooling time constant
Recorded
SCntr
Start counter (Start) reading
