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Industrial Controller Repair

Toshiba VF-AS1 30 kW inverter: heavy internal dust cleaned and fully tested

A Toshiba VF-AS1 30 kW inverter came in packed with dust. We cleaned it out, checked the power and I/O sections, and ran it at 400 V and on a motor. No parts were damaged and it tested normal.

VFAS1-4300PL · Internal Cleaning · IV-Curve Check · 400 V Power-On · 15 Hz Motor Run

Engineering category
Industrial Controller Repair
Equipment model
Toshiba VF-AS1 inverter (30 kW, three-phase)
Service
Industrial Controller Repair
Repair date
June 2026

The repair, step by step

Illustrative 3D model drawn in code to explain the repair. Not a photograph of the customer's equipment.

  1. 1Dust found

    With the cover off, the inside is covered in dust.

  2. 2Cleaned

    The whole unit is cleaned out.

  3. 3Terminals checked

    Input and output sections: no short, normal IV curve.

  4. 4400 V power-on

    The unit powers up and the panel run test gives U, V, W output.

  5. 5Motor run

    A motor runs at 15 Hz with no alarm or abnormal noise.

01

Problem description

A large amount of dust had built up inside the inverter.

02

Confirmed findings

  • After cleaning, the input (L1, L2, L3) and output (U, V, W) sections were checked: no short circuit or damage.
  • An IV-curve tester on the input side showed a smooth loop, which is the normal capacitor charge and discharge pattern, not a short.

03

Repair / engineering method

  • Cleaned the dust out of the whole unit.
  • No parts needed replacing.

04

Tests performed

  • Three-phase 400 V power-on test passed.
  • Run from the operation panel: U, V and W output present.
  • Motor run at 15 Hz: no alarm, no abnormal noise, output normal.

05

Images

  • Inside the inverter as received: busbars and the control board under a thick layer of dust
    As received: dust over the busbars and control board
  • The power section as received, with dust over the power board, busbars and terminals
    As received: the power section
  • The power board after cleaning, with clean copper busbars and wiring
    Power board after cleaning
  • IV-curve tester screen showing a smooth oval loop on the input side
    IV-curve check: normal loop, no short

06

Final result

Cleaned and fully tested; the inverter works normally.

Manufacturer and model names are used only to identify the equipment we repaired. All trademarks belong to their owners; X TRONIC AUTOMATION is an independent repair service and is not affiliated with or endorsed by the manufacturer.

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