GE Industrial Solutions AF-600 FP High Power (460V_575V 150HP and above) - Manual (Page 64)

If the signal is present at the terminal, the control card is defective and must be replaced. If the signal is not present, the problem is external to the frequency
converter. The circuitry providing the signal along with its associated wiring must then be checked.
5.1.4 Programming Problems
Difficulty with frequency converter operation can be a result of improper programming of the frequency converter parameters. Three areas where programming
errors may affect drive and motor operation are motor settings, references and limits, and I/O configuration. See Drive Inputs and Outputs in Section 2.
The frequency converter must be set up correctly for the motor(s) connected to it. Parameters P-02 - P-07 must have data from the motor nameplate entered
into the frequency converter. This enables the frequency converter processor to match the frequency converter to power characteristics of the motor. The most
common result of inaccurate motor data is the motor drawing higher than normal amounts of current to perform the task expected of it. In such cases, setting
the correct values for these parameters and performing the automatic motor adaptation (auto tune) function will usually solve the problem.
Any references or limits set incorrectly will result in less than acceptable frequency converter performance. For instance, if maximum reference is set too low, the
motor will be unable to reach full speed. These parameters must be set according to the requirements of the particular installation. References are set in the F-5#
parameter group.
Incorrectly set I/O configuration usually results in the frequency converter not responding to the function as commanded. It must be remembered that for every
control terminal input or output, there are corresponding parameters settings. These determine how the frequency converter responds to an input signal or the
type of signal present at that output. Utilising an I/O function must be thought of as a two step process. The desired I/O terminal must be wired properly, and the
corresponding parameter must be set accordingly. Control terminals are programmed in the E-0# and AN-0# parameter groups.
5.1.5 Motor/Load Problems
Problems with the motor, motor wiring or mechanical load on the motor can develop in a number of ways. The motor or motor wiring can develop a phase-to-
phase or phase-to-earth short resulting in an alarm indication. Checks must be made to determine whether the problem is in the motor wiring or the motor itself.
A motor with unbalanced, or non-symmetrical, impedances on all three phases can result in uneven or rough operation, or unbalanced output currents. Meas-
urements should be made with a clamp-on style ammeter to determine whether the current is balanced on the three output phases. See Output Imbalance of
Supply Voltage Test procedure.
An incorrect mechanical load will usually be indicated by a torque limit alarm or warning. Disconnecting the motor from the load, if possible, can determine if this
is the case.
Quite often, the indications of motor problems are similar to those of a defect in the frequency converter itself. To determine whether the problem is internal or
external to the frequency converter, disconnect the motor from the frequency converter output terminals. Perform the output imbalance of supply voltage test
procedure (6.3.10) on all three phases with an analog voltmeter. If the three voltage measurements are balanced, the frequency converter is functioning correctly.
The problem therefore is external to the frequency converter.
If the voltage measurements are not balanced, the frequency converter is malfunctioning. This typically means that one or more output IGBT is not switching on
and off correctly. This can be a result of a defective IGBT or gate signal from the gate drive card. Perform the IGBT gate signal test (6.3.11).
5.2 Internal Frequency Converter Problems
The vast majority of problems related to failed frequency converter power components can be identified by performing a visual inspection and the static tests as
described in the test section. There are, however, a number of possible problems that must be diagnosed in a different manner. The following discusses many of
the most common of these problems.
5.2.1 Overtemperature Faults
In the event that an overtemperature indication is displayed, determine whether this condition actually exists within the frequency converter or whether the
thermal sensor is defective. Of course, this can easily be detected by feeling the outside of the unit, if the overtemperature condition is still present. If not, the
temperature sensor must be checked. This can be done with the use of an ohmmeter in accordance with the thermal sensor test procedure.
AF-650 GP and AF-600 FP High Power Service Manual
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