20kVA 3 Phase Frequency Converter Load Issue

Hello everyone! I’m hoping you can help with a question. We had the 20kVA 3-phase frequency converter HZ-50-3320, and now have it installed, and are starting to test it. It powers on, the voltage/frequency is steady and everything looks good until we add a load. As soon as we put any load at all on it, one of the phases drops out, and it starts beeping. Any thoughts on what might be causing this issue?

To solve the problem, please further feedback on the following information to us.
1. Please provide us with the specific specification information of the connected load of the converter, such as load power, rated voltage, rated current, etc.
2. Now, open the converter side covers "the converter will still be in the warranty period, no worries", and power on the converter, then take a video showing us the internal main circuit boards, especially the ones with red LED indicators and beeping sound, and show us the converter display as well while the converter is running.

ATO wrote:
Thanks much for the follow up. I think this may be a frustrating one to solve as I came in this morning to gather data on the error and answer the questions below, and the system worked perfectly. I have no idea why I was getting errors yesterday after multiple attempts, but today it handles the load with no issues and seems to work fine. All I know to do at this point is use it and if the error comes back, I’ll check the boards and see if the LEDs change state. If it happens again, I’ll try to take a video of the voltages as well.
Even though it is working at the moment, I will try to give as much data as I can in case the problem returns. I’ve attached a picture of the data plate, and a short video with our attached equipment in its initial start-up state.
For the load, it should peak at no more than 17A at 380V (running current should be less). Our load is 380V, 3-phase +N, G. The input is 208V, 3-phase +G.

Sosa wrote:
1. Okay, for the load, you mentioned "it should peak at no more than 17A at 380V", can you tell us what type of load this is? And the power of the load, what is the rated current? Also are you sure the maximum peak current is only 17A?
2. Also can you tell us in detail what is the process by which the converter fails? For example, after setting the output voltage and frequency, does it fail immediately when the load is applied at the beginning, or does it fail again after adding other loads in the middle?
3. You can disconnect the input power of the converter, discharge the internal capacitor (make sure the CBB65 feedback capacitor voltage is <5V), and then re-plug and fix all the plugs on the W-phase driver board (as shown in the figure below), and test again. This is because sometimes bad cable contact can also cause this problem.

We continue to have some glitches using the converter. Often it trips when a load is applied, but after resetting once or twice it works fine for the rest of the day. It seems to happen when I’m not there, but I got a coworker to catch it in the act and take some pictures. Below is what we see on the front panel when it is in the error state. The attached picture is of the control boards, and you can see the red LED illuminated on the upper and lower boards on the right. I look forward to hearing your thoughts.

Sosa wrote:
If the converter is working properly now, you can continue to use it normally.
The load peak current is 17A at 380V, which can be used normally.

When I measured the running loads, the highest I saw on any single phase was 6A. The manufacturer of the equipment attached to the converter assured us that there were no peak loads that reached 17A, even during startup. I no longer think that is true.
Talking to coworkers this morning, the frequency converter only gives an error when the load is initially applied. I re-plugged the connectors just in case it is a connection problem, but at this point, I am not convinced the converter is the problem. I feel our equipment is peaking higher than expected, and I need to diagnose that side of the equation next.

Sosa wrote:
If your frequency converter peaks higher than expected, can you find other ways to measure and verify this peak current?
Also, you can try to fix the connector plug of the device first, then start the converter, after setting the voltage and frequency, turn on the output circuit breaker and connect your machine load directly. Please check this way to start, is there any fault?

ATO wrote:
Thanks for the suggestion. I just want to make sure I understand the order you are suggesting. Is it the following?
1. Turn on the load so that it is connected.
2. Start converter: at set voltage/frequency.
3. Then turn on the output breaker.

Sosa wrote:
Yes, that's right. You can try using this boot method.