CG Drives & Automation 01-7492-01r1 Functional description 99
Extend data [22J]
Additional motor parameters for Permanent Magnet
Synchronous Motors (PMSM) and Synchronous Reluctance
motors.
This menu is only available if PMSM or Sync Rel is selected
in menu [22I].
BEMF [22J1]
Set the back EMF of the motor at the nominal operating
point. This parameter may not be explicitly available from
the manufacturer, but can then be computed from the
electrical constant Ke and the nominal speed.
Rs (mΩ/ph) [22J2]
Set the per phase resistance.
Lsd (mH/ph) [22J3]
Set the per phase d-axis inductance.
Lsq (mH/ph) [22J4]
Set the per phase q-axis inductance.
11.2.3 Motor Protection [230]
This function protects the motor against overload based on
the standard IEC 60947-4-2.
Motor I
2
t Type [231]
The motor protection function makes it possible to protect
the motor from overload as published in the standard IEC
60947-4-2. It does this using “Motor I2t Current [232]” as a
reference. The “Motor I2t Time [233]” is used to define the
time behaviour of the function. The current set in [232]
should be allowed infinite in time by the motor (thermal)
specification/design. If for instance in [233] a time of 1000 s
is chosen the upper curve of fig. 93 is valid. The value on the
x-axis is the multiple of the current chosen in [232]. The
time [233] is the time that an overloaded motor is switched
off or is reduced in power at 1.2 times the
current set in [232].
22J1 BEMF
Default: Motor dependent (V)
Range: 100-700 V
Resolution 1 V
22J2 Rs (mΩ/ph)
Default: Undef
Undef Undefined
Range: 0.001-40000 mOhm
22J3 Lsd (mH/ph)
Default: Undef
Undef Undefined
Range: 0.001-10000.000 mH
22J4 Lsq (mH/ph)
Default: Undef
Undef Undefined
Range: 0.001-10000.000 mH
231 Mot I
2
t Type
Default: Trip
Off 0 I
2
t motor protection is not active.
Trip 1
When the I
2
t time is exceeded, the AC
drive will trip on “Motor I
2
t”.
Limit T 2
This mode helps to keep the inverter
running when the Motor I2t function is just
before tripping the AC drive. The trip is
replaced by current limiting with a
maximum current level set by the value
out of the menu [232]. In this way, if the
reduced current can drive the load, the
AC drive continues running. If there is no
reduction in thermal load, the drive will
trip.
Limit Spd 3
This mode is similar to “Limit T” but it
limits the speed instead of the torque.
This can be useful in for e.g. pump
applications where the load increases
with the speed. A minimum allowed
speed can be set in menu [238]
NOTE: When Mot I2t Type=Limit, the AC drive can
control the speed < MinSpeed to reduce the motor
current.
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