IndustrialDriveDataDrive Board & Diagnostic Database
AC drive diagnostic model reference

TD900-4T0015G

This model record starts with a documented IGBT turn-off path observation: its drive stage uses an HCPL-3120-type driver arrangement with a diode/resistor/capacitor network important to gate discharge behavior.

Record facts

Recorded diagnostic areaIGBT gate turn-off path
Observed driver reference3120 driver stage
Observed diode markingM5C / replacement observation P5C

Service notes

  • An in-circuit reading may conceal an open diode in the turn-off network because adjacent resistors provide a parallel path.
  • Gate-drive defects must be resolved before returning a replacement power module to full-power operation.

Related technical records

E019
Current Detection Circuit Fault

The drive reports E019 during power-up or operation, potentially without a genuine motor overcurrent event.

Open →POFF
Input Undervoltage / Drive-Board Supply Indication

The keypad displays POFF immediately after power-up or only when the motor is commanded to run.

Open →Circuit
Emerson TD900 IGBT Turn-Off Drive Stage

A documented TD900 gate-drive observation shows a 3120 driver arrangement using a diode/resistor/capacitor network to improve IGBT turn-off charge removal where no negative gate supply is used.

Open →Workflow
Emerson TD900 E019 Current-Detection Investigation

The TD900 presents E019 or a suspected false current indication.

Open →