Setting ranges
0 = Inactive
0.1Hz to 5.0Hz.
When the motor loading increases, the motor
slows down. Conversely, if load reduces,
speed increases. The object of slip compensa-
tion is to keep the motor speed constant under
varying load.
As illustrated above, slip compensation raises
the motor speed to compensate for a load
torque increase. Function 68 sets the ‘com-
pensation frequency’ C
f
for slip compensation.
The exact value for the % slip at full load will
vary from one motor to another.
Example: Typical rating plate data:
Number of poles p = 4;
Base frequency f = 50Hz;
Shaft rotational speed at full load, N
L
= 1420 rpm.
Calculated synchronous speed (ie the speed of
the rotating field in rpm), N
S:
N
S
=
f x 120
=
50 x 120
= 1500rpm
p
4
Set Function 68 =
(N
S
- N
L
) x f
N
S
=
(1500 - 1420) x 50
1500
= 2.7Hz
Motor 1 only.
Setting range
0 = Torque vector control inactive,
and standard V/f control applies.
1 = Torque vector control active.
To obtain the maximum amount of motor
torque under a variety of operating conditions,
the output torque is accurately calculated by
the inverter software in accordance with load
conditions. The voltage vector is controlled to
the optimum value based on the result of the
calculation. Torque vector control can only be
used for Motor 1. The motor capacity must be
within the vector control range for the invert-
er. Refer to Function 70.
NOTES
1 If torque vector control is selected it is
advisable to use the Automatic Tuning
facility, Function 74, wherever possible,
for optimum control of the driven load.
2 If Function 43 = 2 (X4 terminal VF2
function), torque vector control is inactive.
Torque boost 2 is applied.
Motor 1 only.
Compensates for a motor of capacity different
from that of the inverter.
Setting ranges
0 = Motor capacity one frame size
above inverter capacity.
1 = Equal ratings.
2 = Motor capacity one frame size
below inverter capacity.
3 = Motor capacity two frame sizes
below inverter capacity.
Motor 1 only.
Setting range
0.01 to 99.9 amps
Functions 71 and 72 are preset for a motor of
nominal rating equal to the inverter rating, but
40
69 Torque vector control
70 Motor 1 capacity
71 Motor 1 rated current
72 Motor 1 no-load current
68 Slip compensation
Torque
Speed
Slip compensation
Synch.
speed N
S
Typical loss of
speed with
increased load
Summary of Contents for Jaguar VXS
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