Chapter 6
Troubleshooting
6–24
For proper drive operation it is necessary to have:
A. A specific phase sequence of the motor leads (M1 M2 M3, M1
M3 M2 etc.)
B. A specific sequence of encoder leads (pulse A leads B etc.)
These sequences determine the direction of rotation of the motor
shaft on application of torque. An improper sequence can result in
either the motor rotating the wrong direction or no production of
torque. This test is used to ensure the above conditions by
applying a positive torque and manually checking motor rotation
and velocity feedback.
Set parameter 256 (Autotune Diagnostics Selection) Bit 3 to a value of 1:
Running the Inductance Test
A measurement of the motor inductance is required to determine the
references for the regulators that control torque. This test measures the
motor inductance and displays it in Lsigma Tune [Leakage Inductance]
(parameter 237).
When running this test, you should be aware of the following:
• The motor should not rotate during this test although rated voltages
and currents are present and the possibility of rotation exists. For en-
coderless systems, you must visually verify that the motor does not
rotate.
• This test is run at rated motor current and by–passes the normal cur-
rent limit functions.
Before running the inductance test, make sure that you have entered the
correct motor nameplate information.
To run the inductance test:
1. Set bit 2 in Autotune/Diagnostics Selection (parameter 256).
2. Enable the drive.
The drive enable light turns off when the test is complete. The
inductance test runs for approximately 1 minute. When a reading is
obtained in Lsigma Tune, perform the resistance test.
Typical values for per unit inductance are in the range of 15% to 25%
motor impedance. The value shown in Lsigma Tune is a percent value.
If you are using long wiring runs, the typical value for per unit
inductance should increase by the ratio of wiring inductance to motor
inductance.
Phase Rotation Tests
Sequential Torque Block
Tuning
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