Baldor VS1GV21-1B, Installation & Operating Manual

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Customizing Your Application 8-1 MN765
Chapter 8
Customizing Your Application
8.1 Customizing Your Application
Manually Tuning the Control
In some applications the drive cannot be accurately auto tuned. In these cases, it is necessary to calculate the values
needed to tune the drive and manually enter these calculated parameter values. In case the autotune feature cannot be
used, enter the motor rated and magnetizing current parameters as described below and execute “Calc Motor Model”. Use
the current proportional, current integral and speed gains calculated after this step as the starting point for manual fine-
tuning.
Motor Mag Amps Parameter
This parameter is located in the Level 2, Motor Data Block. This parameter is normally entered using the nameplate data
(motor no load amps) or auto tuned. If no other data is available, set Motor Mag Amps parameter to about 40% of the motor
rated current stated on the nameplate.
The following procedure should be used for setting the Motor Mag Amps parameter with the motor coupled to the load:
1. Adjust the Motor Mag Amps parameter to 40% of the motor nameplate full load current rating.
2. Give the controller a speed command input of 80% of the Base Speed on motor nameplate.
3. Observe the Motor Rated Volt parameter on the keypad Diagnostic display. Ideally, it should be 80% of motor nameplate
voltage. By raising the Motor Mag Amps parameter value, the motor voltage will increase proportionally. By reducing the
Motor Mag Amps parameter value, the motor voltage will decrease proportionally.
4. While the motor is running, adjust the Motor Mag Amps parameter until the display indicates the proper voltage (80% of
motor rated).
Electrical Slip Frequency Parameter
This parameter is located in the Level 2, Motor Data Block. The slip frequency may be calculated from nameplate data or
auto tuned.
Fslip = Rated Freq – [ (Rated RPM x Number of Motor Poles) / 120 ]
Current Prop Gain Parameter
This parameter is located in the Level 1, Motor Control Block. The value is set at the factory and is recommended to be
changed with Auto Tune or “Calc Motor Model”. Do not attempt to change the value manually.
Current Int Gain Parameter
The Current Int Gain parameter located in the Level 1 Motor Control Block is factory set and is suitable for most
applications.
Speed Prop Gain Parameter
The Speed Prop Gain parameter located in the Level 1 Motor Control Block is factory set to 5. This gain may be increased
or decreased to suit the application. Increasing the Speed Prop Gain parameter will result in faster response, excessive
proportional gain will cause overshoot and ringing. Decreasing the Speed Prop Gain parameter will cause slower response
and decrease overshoot, ringing, and possibly instability resulting in overcurrent faults.
Speed Int Gain Parameter
The Speed Int Gain parameter in the Level 1 Motor Control Block is set to 10 Hz and may be set at any value. See also,
PI Controller later in this section. Setting the Speed Int Gain parameter to 0Hz removes integral compensation that results in
a proportional rate loop. This selection is for systems where overshoot must be avoided and stiffness (ability of the controller
to maintain commanded speed with varying torque loads) is not required.
Increasing values of the Speed Int Gain parameter increases the stiffness of the controller. Typical setting is 10 Hz. If the
Speed Prop Gain parameter and the Speed Int Gain parameter are set too high, an overshoot condition can occur.
To manually tune the control, the following procedure is used with the load coupled to the motor:
1. Set the speed Integral Gain parameter = 0 (remove integral gain).
2. Increase the Speed Prop Gain parameter setting until adequate response to step speed commands is attained.
3. Increase the Speed Integral Gain parameter setting to increase the stiffness of the drive. Note: It is convenient to monitor
speed step response with a strip chart recorder or storage oscilloscope connected to J1A-6 or -7 with Level 1, Output
Block Analog Out #1 or #2 set to ABS SPEED, 0 VDC = zero speed. See Chapter 5 for a discussion of analog outputs.
Additionally, the scope function within Mint WorkBench is a good tool to use while tuning the drive speed loop.