IndustrialDriveDataDrive Board & Diagnostic Database
Regenerative energy / DC-bus overvoltage evidence

Hitachi SJ300 / L300P Regeneration and Deceleration Load Path

Routes E07 overvoltage cases through machine energy, stop timing, ramp profile, descending or overhauling loads and DC-bus rise before the brake unit or sensing path is blamed.

Field evidence path8 min read

Scope of this technical record

Field route for E07 cases caused by regenerative load energy, aggressive deceleration or high-inertia stop conditions.

Safety boundary

Load and braking evidence can involve hazardous moving machinery and high DC voltage. Follow machine lockout and drive isolation procedures.

Hitachi regeneration load path

1Stop event
→
2Machine inertia
→
3Motor regenerates
→
4Bus rises
→
5Brake demand

The route keeps high-inertia and overhauling loads separate from board faults.

The motor can become the source

During a rapid stop or overhauling load, the motor can return energy to the drive. The DC link rises because the machine is pushing energy into the electronics. This is why a longer ramp, coast-to-stop or brake-path change can transform an E07 case.

The page exists so E07 is not treated as a failed board when the actual evidence is machine energy and inadequate absorption.

Field record checklist

  • Load type
  • Stop timing
  • Ramp time
  • Overhauling or high-inertia behaviour
  • Effect of longer decel

Technical basis and reference documents

This is an independent editorial technical reference. Original manufacturer documentation remains controlling for installation, repair and commissioning decisions.

SJ300 Troubleshooting and Maintenance, Chapter 6AutomationDirect / Hitachi manual mirror

Defines the status-at-trip context and links E07 to DC-bus overvoltage evidence.

L300P Series Inverter Quick Reference GuideHitachi Industrial Equipment Systems

Lists E06 braking resistor overload and E07 overvoltage protection caused by regenerative motor energy.

SJ300 Dynamic Braking Selection ChartHitachi AC Drive

Shows that braking capability, resistor value, duty cycle and external braking units vary by rating.

SJ300 & L300P Series Inverters Service ManualHitachi America / public service-manual mirror

Describes overvoltage detection by regenerated motor energy or high incoming AC voltage and highlights BRD-duty context.

Evidence intake

Turn this record into a qualified service request

A repair decision is much more reliable when the request includes the exact identity of the drive, the first fault evidence and the machine condition when the symptom appeared.

  • Complete drive type code / MLFB or nameplate model
  • Fault code, fault value and first event before reset
  • When the event appears: power-up, enable, ramp, run, decel or stop
  • Motor/cable connected or isolated during the symptom
  • Visible board, option-card, module and connector identifiers
  • Previous repair history, replacement parts and repeat-failure pattern
Prepare request →