E07: DC-bus overvoltage during deceleration, regeneration or high-line operation

What E07 is really asking

E07 is often treated like a one-line fault code. In service, the useful question is why the DC link rose above threshold. The answer can be supply-side, machine-side, braking-side or sensing-side.

A stop-time E07 usually points to energy returning from the motor into the DC link. A power-up or idle E07 with normal machine load points elsewhere: high line, wrong voltage class, measurement/sensing evidence or a control interpretation problem. This page keeps those routes separate.

Deceleration overvoltage is not automatically a failed drive

When a high-inertia machine stops quickly, the motor becomes a generator and sends energy back to the drive. If the ramp is too aggressive or the braking route cannot absorb energy, the DC link rises and E07 follows. In that case, replacing a board can leave the real problem untouched.

The evidence package should include ramp settings, load behaviour, resistor value, duty cycle, thermal switch state and whether the fault disappears when the machine coasts or uses a longer deceleration time.

• Trip at stop or decel: start with regeneration and brake route.
• Trip at idle: start with line and sensing evidence.
• Trip after repeated stops: check resistor duty and heat evidence.
• Trip after a retrofit: verify resistor selection and braking-unit arrangement.

Repair boundary

Only after line voltage, load inertia, ramp profile and brake resistor route have been closed should the case move to DC-bus sensing or control-board repair. That boundary is important because SJ300 / L300P drives are old enough that used-board replacement is common and mis-matched donor boards can introduce new faults.

A useful E07 request therefore needs the model suffix, voltage class, frame, braking hardware and machine duty. Without that, the case remains a symptom report rather than a repair decision.