Transformer/IGBT/Driver Board Testing in Frequency Converter

Frequency Converter, also known AC power supply/frequency changer, is an electric supply conversion device. It converts the alternating current in the electric supply through AC-DC-AC and outputs a pure sine wave. It converts the alternating current in the mains through AC-DC-AC and outputs a pure sine wave. In this article, ATO will introduce you to how to test a 9V transformer/IGBT/driver board in a frequency converter. In order to understand the testing process more clearly, we have posted a video explanation, please watch the video for more information.

How to Test 9V Transformer in a Frequency Converter?

We’ll introduce you to how to test a 9V transformer, also used as a power supply for the display panel of the frequency converter.

Firstly, don’t forget to discharge the converter for 30 min or above. And make sure that the voltage of the DC capacitor is no more than 5V DC. Since it’s actually used to power up the display control panel, the ratings of the 9V transformer are small on the whole. You can figure out whether the transformer works well by measuring its output voltage.

1. Remove the left cover of the variable frequency power supply, aka the frequency converter, there is a small hole near the display controller. Use a Phillips screwdriver to unscrew the fixing screw inside the hole.
2. Then you can open up the display control panel and check out the circuitry on the rear. On the leftmost end of the circuit board are the power supply terminals. The 9V transformer outputs through them to energize the whole circuitry. The screw terminals are marked with 9V underneath. As you can see, there are marked with 0V and 9V on the circuit board.
3. Reconnect the wires to the terminals. If the measured voltage is between 9 and 11V, the 9V transformer is normal.

Related Video

IGBT Module Testing

Then, do an IGBT module testing within the frequency converter using a multimeter. As we highlighted in the previous paragraph, be sure to complete these general steps before testing. Please turn off the power and let it discharge for 30 min or you could discharge the capacitor directly.

The IGBT module is usually located under the absorber plate and is connected to the driver board through multiple twisted pairs.

• It needs to be measured the resistance of the twisted pairs of blue and black, green and black, red and black, and yellow and black individually.
• Unplug the connector and measure it with a multimeter in the ohm range. If the display is infinite (or disconnected), the twisted pair is normal.
• Unplug the other three twisted pairs, measure their resistance respectively and record it.

Broken IGBT Testing

1. G1 and E1 belong to one pair while E2 and G2 belong to the other.
2. Set the multimeter in ohm range.
3. The meter reads 1.1Ω between G1 and E1.
4. On the other hand, it shows 1.4Ω between G2 and E2.
5. The resistance is not infinite so that the conclusion is the IGBT is broken.

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Frequency Converter Driver Board Testing

As always, remember to finish the above routine procedures before getting into the major part. Let the converter discharge for above 30 min, make sure the DC capacitor is less than 5V in voltage and disconnect the bridge rectifier.

• Removed wires from the bridge rectifier and wrap up their heads in electrical tapes.
• Complete the input wiring to the power supply, power ON.
• Turn on the input circuit breaker, push the Power ON button.

Let’s move on to the driver board. AC voltage and DC voltage measurements are needed.

Measure AC voltage

Measure the AC voltage of black, yellow, blue and white twisted pair wires respectively with a multimeter. The normal voltage value falls between 24V and 30V AC. We suggest recording these four groups of voltage data for further discussion with technicians. In our case, the voltage remains constant at 29V or so.

Measure DC voltage

Then measure the DC voltage of these double-colored twisted-pair wires. Put the multimeter into the DC voltage range. The normal voltage range is between 1.0 and 1.5V DC (The previous version measures below 4.2V. ) Also, you’d better record these data for quick inquiry during your communication with technicians.

Related Video

The above is a detailed description of the 9V transformer/IGBT/driver board test. If you want to know more about frequency converters, please visit ATO.com. 1 phase frequency converter and 3 phase frequency converter with power capacities from 500 VA to 600 kVA are available, which are perfect solutions for home appliances, industrial power conversion, laboratory testing, aviation, military applications, and more.