East EA990G5, Руководство по обслуживанию

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Table 6-21 The frogile component of 30kVA bypass board
Components Tag Number Specifications
Alternative
specification
Bypass SCR Q1,Q2,Q3,Q4,Q5,Q6 VS-70TPSPBF
Fig.6-21 The key components identification of 30kVA bypass board
The detailed maintenance steps are as follows:
Step 1: Check whether the copper foil is corroded and rusted on the entire I/O board. You can use a
multimeter to assist in the inspection. If there is corrosion, the copper foil needs to be re-soldered.
Step 2: Visually inspect the entire I/O board for obvious burns or explosions, and replace if necessary.
Step 3: Measure the resistance of the bypass thyristor (SCR) with the ohm gear of the multimeter. The normal
resistance should be around 20 Ω . If not, it needs to be replaced.
Note: When replacing the SCR, it is necessary to apply thermal paste on the back of the device. If the
corresponding insulating gasket is blackened, burned, burned through, burned, etc., it needs to be replaced
together.
After completing the inspection work in steps 1-3, replace the damaged device; after replacing the device,
use the shorting cap to short-circuit J2 of the rectifier control board CT1 and J2 of the inverter control board CT2,
and then follow the steps shown in Figure 6-20. Connection method for drive test. The test waveforms of each key
device are shown in Table 6-20.
Fig.6-20 The connection of drive test circuit of 30kVA bypass board