Emerson unidrive sp User Manual page 231

Safety Mechanical
Product
Information information Installation
11.21.8 Catch a spinning motor
6.09 Catch a spinning motor
RW Uni
OL 0 to 3
CL 0 to 1
Open-loop
When the drive is enabled with this parameter at zero, the output
frequency starts at zero and ramps to the required reference. When the
drive is enabled with this parameter at a non-zero value, the drive
performs a start-up test to determine the motor speed and then sets the
initial output frequency to the synchronous frequency of the motor.
The test is not carried out and the motor frequency starts at zero if one of
the following is true.
• The run command is given when the drive is in the stop state
• The drive is first enabled after power-up with Ur_I voltage mode
(Pr 5.14 = Ur_I).
• The run command is given with Ur_S voltage mode (Pr 5.14 =
Ur_S).
With default parameters the length of the test is approximately 250ms,
however, if the motor has a long rotor time constant (usually large
motors) it may be necessary to extend the test time. The drive will do this
automatically if the motor parameters including the rated load rpm are
set up correctly for the motor.
For the test to operate correctly it is important that the stator resistance
(Pr 5.17 or Pr 21.12) is set up correctly. This applies even if fixed boost
(Pr 5.14 = Fd) or square law (Pr 5.14 = SrE) voltage mode is being used.
The test uses the rated magnetizing current of the motor during the test,
therefore the rated current (Pr 5.07, Pr 21.07 and Pr 5.10, Pr 21.10) and
power factor should be set to values close to those of the motor,
although these parameters are not as critical as the stator resistance.
For larger motors it may be necessary to increase Pr 5.40 Spin start
boost from its default value of 1.0 for the drive to successfully detect the
motor speed.
It should be noted that a stationary lightly loaded motor with low inertia
might move slightly during the test. The direction of the movement is
undefined. Restrictions may be placed on the direction of this movement
and on the frequencies detected by the drive as follows:
Pr 6.09
0
1
2 Detect positive frequencies only
3 Detect negative frequencies only
Closed-loop vector and Servo
When the drive is enabled with this bit at zero, the post ramp reference
(Pr 2.01) starts at zero and ramps to the required reference. When the
drive is enabled with this bit at one, the post ramp reference is set to the
motor speed.
When closed-loop vector mode is used without position feedback, and
catch a spinning motor is not required, this parameter should be set to
zero as this avoids unwanted movement of the motor shaft when zero
speed is required. When closed-loop vector mode without position
feedback is used with larger motors it may be necessary to increase
Pr 5.40 Spin start boost from its default value of 1.0 for the drive to
successfully detect the motor speed.
5.40 Spin start boost
RW Uni
OL
0.0 to 10.0
VT
Unidrive SP Free Standing User Guide
Issue Number: 1
Electrical Getting Basic
Installation Started parameters
US
0
1
Function
Disabled
Detect all frequencies
US
1.0
www.controltechniques.com
Running the SMARTCARD
Optimization
motor operation
If Pr 6.09 is set to enable the catch a spinning motor function in open-
loop mode or closed-loop vector mode without position feedback,
(Pr 3.24 = 1 or 3) this parameter defines a scaling function used by the
algorithm that detects the speed of the motor. It is likely that for smaller
motors the default value of 1.0 is suitable, but for larger motors this
parameter may need to be increased. If the value of this parameter is too
large the motor may accelerate from standstill when the drive is enabled.
If the value of this parameter is too small the drive will detect the motor
speed as zero even if the motor is spinning.
11.21.9 Position modes
13.10 Position controller mode
RW Uni
OL
CL
This parameter is used to set the position controller mode as shown in
the table below.
Parameter
value
0
1
2
3
4
5
6
Rigid position control
In rigid position control the position error is always accumulated. This
means that, if for example, the slave shaft is slowed down due to
excessive load, the target position will eventually be recovered by
running at a higher speed when the load is removed.
Speed
Reference
Technical
Onboard Advanced
PLC parameters Data
0 to 2
0 to 6
Mode
Position controller disabled
Rigid position control
Rigid position control
Non-rigid position control
Non-rigid position control
Orientation on stop
Orientation on stop and when
drive enabled
Actual
Equal Areas
UL Listing
Diagnostics
Information
US
0
Feed forward
active
t
231