Guidelines for Basic Drive Testing and Troubleshooting
As a first step before doing any tests, please refer to some of the general inspection steps as noted in the Drive Maintenance (General Inspections and Repairs) FAQ page Here.
Static Tests (Dry Tests)
To do the static tests, first make sure the power supply to the drive is disconnected (no power on drive – doing these tests with power on will damage the Multimeter). Set the Multimeter to Diode Voltage test mode as follows:
Rectifier Circuit
To test the incoming (power supply circuit), connect the Black Probe of the Multimeter to the P+ terminal of the drive and the Red Probe to each of the R, S and T terminals, each time measuring the voltage. After that, connect the Red Probe of the Multimeter to the P- terminal of the drive and the Black Probe to each of the R, S and T terminals, each time measuring the voltage.
* Please note, for small drive units without a P- terminal the drive needs to be opened to do this test – please see details at the end of the IGBT Circuit test section.
Results: Expected values should be approximately ~0.4V. The results for different kW drives will differ, but the 6 measurements should be very similar (for drives larger than 160kW not lower than 0.2 and for drives smaller than 160kw not lower than 0.3). If any of the measurements tests as Open Loop or values that differ greatly from the expected values noted above, it is most likely that the Rectifier has been damaged. In such an event, please contact us for support.
IGBT Circuit
To test the outgoing (power output circuit), connect the Black Probe of the Multimeter to the P+ terminal of the drive and the Red Probe to each of the U, V and W terminals, each time measuring the voltage. After that, connect the Red Probe of the Multimeter to the P– terminal of the drive and the Black Probe to each of the U, V and W terminals, each time measuring the voltage.
* Please note, for small drive units without a P- terminal the drive needs to be opened to do this test – please see details later in this section.
Results: Expected values should be approximately ~0.4V. The results for different kW drives will differ, but the 6 measurements should be very similar (for drives larger than 160kW not lower than 0.2 and for drives smaller than 160kw not lower than 0.3). If any of the measurements tests as Open Loop or values that differ greatly from the expected values noted above, it is most likely that the IGBT has been damaged. In such an event, please contact us for support.
To download the Excel test file for printing and noting the measurements, please download the IGBT and Rectifier Tests Excel file Here.
Small Drive Testing (without P- Terminal)
Small drive units without a P- terminal (some drives up to 2.2kW) needs to be opened to access the Power Board to complete the above tests. For all tests above where a P- terminal is used for testing, please use the terminal as indicated in the image below as the P- terminal.
Dynamic Tests (Wet Tests)
If the Static Test results are normal, the Dynamic Tests can be performed (power-on tests). The following points must be noted before and after power-up:
Before Powering On
Confirm that the input voltage is correct and check whether the connection ports of the drive are correctly connected and whether any of the connections are loose (abnormal connections may sometimes cause the drive to malfunction).
After Powering On
Check that the DC Bus Voltage is normal (should be ~ 1.414 x the AC Power Supply Voltage) – can be done by measuring the DC Voltage between Terminals P+ and P- and also by checking the DC Bus Voltage as displayed on the drive keypad (use the Shift Key on the keypad to scroll through the different display values: Frequency, Amps, DC Bus Voltage and Output Voltage). With 30kW and larger drives one should typically hear the DC Contactor pulling in.
If the DC Bus Voltage is normal and the Operating Panel (Keypad) does not work (no display) or flashes regularly or displays E.Pan, it could be caused by a faulty Keypad Socket or damaged Keypad. Firstly, remove the Keypad and check whether the LED indicator on the Control Board is on after the drive is powered on. If not (first switch off all power supply and wait 15mins before doing this), disconnect and connect the cable between the Control Board and Power Board (or Drive Board for units larger than 22kW) to ensure they are connected properly. If the issue persists (after power on again), please contact us for support (could be damaged Drive/Power Board). If the LED indicator does go on, check that the pins of the Keypad Socket on the Control Board are in good working condition. If possible, replace the Keypad to confirm whether it’s a faulty Keypad. If the Keypad seems to be in working condition, measure the DC Voltage on the Control Board between the +24V and COM Terminals to confirm a ~24V reading is obtained – if not, please contact us for support (could be damaged Control Board).
Please note, for an E.Pan error display on a Solar Drive – if this error is being displayed momentarily, this could be due to the DC Bus Voltage dropping below 100V – with Solar Drives this could typically happen when the Dormancy Voltage (Sleep) is set very low, creating a scenario where the drive is still busy decelerating before reaching the Dormancy Voltage (which should normally trigger Alarm Ar.01) while the DC Bus Voltage already dropped below 100V, which would then cause the communication error being displayed on the keypad. This could also be caused by a poor connection within the PV Array supplying the drive with power (sudden voltage drop occurs when a load is added).
If the Operating Panel (Keypad) displays a fault (Error Code) after powering on, please look up the Fault Code from the Fault Codes and Descriptions log (listing possible reasons/causes and solutions) Here.
For additional Fault Information it’s also very helpful to review the Error Log (last 3 errors and related information stored at the time of the fault). To download the Excel Error Log file for printing and noting the info, please download the Excel Error Log File Here (when contacting us for support it might be easier to simply take a video of the error log values by entering through all the parameters and sending us the video).
If all the above is in order, check whether the motor parameters are correct and whether any abnormal parameter settings can be identified – if so, doing a factory reset could be a good idea (for VSDs set A0-09=1 and for Solar Drives (Single-Line Keypad Display models) set FP-01=1).
Start the Drive
Next, start the drive under no-load (no motor connection). If the drive immediately trips when attempting to start it, it could be due to a faulty cooling Fan (or fan short circuit). Firstly, try and set the fans to run during power on (instead of only during running) – on a VSD, set b2-23=1, on a Solar Drive (Single-Line Keypad Display models), set F8-48=1. If the drive then trips immediately after powering it on, this typically indicates a faulty fan. To isolate the faulty fan the fans can be disconnected one at a time (first switch off all power supply and wait 15mins before doing this) to identify the specific fan causing the trip. If identified, please replace the fan, otherwise please contact us for support.
If the drive starts up, test the U, V, W output voltages. If there is a phase loss, phase unbalance, etc., the Drive/Power Board is most likely faulty. In such an event, please contact us for support.
If the output voltage is normal (no phase loss, phase unbalance), a load test can be done (with motor connected – when testing, it is best to test at full load). Check whether the current displayed on the Keypad is too high or has large variations, similarly, also check the output voltage as displayed on the keypad. After this, also test whether the output voltage and current are balanced on the U, V and W output terminals.
If none of the above steps helped identify and/or resolve the issue, please contact us for support.
Contacting us for Support
Please note, when contacting us for support, please try and provide as much information as possible, such as:
- Photo of the Drive Nameplate.
- Photo of the Motor Nameplate.
- Photo’s/Video’s showing the installation and setup.
- Details regarding the specific application and configuration/setup used.
- Details regarding the undesired/unexpected behaviour/observations (ideally with photo/video evidence showing the occurrence).
- Error Log information as obtained from the drive – please download the Excel Error Log File Here (it might be easier to simply take a video of the error log values by entering through all the parameters and sending us the video).
