VAMP 150 - Page 42

VAMP 150 Motor protection relay
Technical Description
VAMP Ltd
14
Vamp 24h support phone : +358 (0)20 753 3264 VM150.EN005
Ambient temperature correction for the maximum allowed
continuous current used by the thermal overload stage. The
slope is defined by the user giving the relative motor currents
at ambient temperatures +40 °C and +70 °C. The default
values are I
MAX40
= 100% and I
MAX70
= 78%.
The device is updating the thermal image continuously. If the
calculated temperature exceeds the given alarm limit Θ
ALARM
the stage gives out a start signal. When the temperature
exceeds the trip level Θ
TRIP
the stage activates the trip signal.
The start and trip signals are controlling the output relays via
the user configured output relay matrix. The start signal is not
released until the temperature is Θ
DEADBAND
below Θ
MAX
. The
temperature dead band Θ
DEADBAND
is 10 % x Θ
TRIP
.
Whenever the current is below I
STOP
the motor is supposed to
be stopped and a longer time constant is used for modeling the
temperature. The maximum current for a stopped motor I
STOP
is 10 % x I
MOT
.
Parameters of the thermal overload stage:
T> (49M)
T> (49M)T> (49M)
T> (49M)
Parameter:
Parameter:Parameter:
Parameter: Value/unit:
Value/unit:Value/unit:
Value/unit:
Measured
value
T> % Temperature rise of stator
T> xI
MOT
Max. allowed continuous
current as compared to I
MOT
Alarm % Temperature alarm limit
Tau min Time constant of the motor
Tau2 xTau Cooling time multiplier for
Tau
I
MAX40
xI
MOT
Relative allowed overload
when Θ
AMB
is +40 °C
I
MAX70
xI
MOT
Relative allowed overload
when Θ
AMB
is +70 °C
Setting
values
Tamb
°C
Ambient temperature
SCntr Start counter (Start) reading
TCntr Trip counter (Trip) reading
Load A 1s mean value of pre-fault
phase currents as compared to
I
MOT
Flt A Max. value of fault current as
compared to I
MOT
FltT % Max. value of fault
temperature
Recorded
values
EDly % Elapsed time as compared to
the set operate time, 100% =
tripping