Siemens SINAMICS V90, SIMOTICS S-1FL6 Error F7900: Motor blocked/speed controller at its limit

Industrial motor drive · taken from the manufacturer’s manual, pages cited

Fault codeF7900

The motor is blocked or the speed controller is at its limit due to torque exceeding limits or oscillating speed below 120 rpm. The manual's first action is: “['• Check whether the servo motor can rotate freely or not.\n• Check the torque limit.\n• Check the inversion of the actual value.\n• Check the motor encoder connection.\n• Check the encoder pulse number.']”

Model
Siemens SINAMICS V90, SIMOTICS S-1FL6
Display shows
Motor blocked/speed controller at its limit (F7900)
Type
Fault code
Source
Manual p. 298

What F7900 means

Motor blocked/speed controller at its limit p. 298

Common causes

  • The servo motor has been operating at the torque limit longer than 1 s and below the speed threshold of 120 rpm . This signal can also be initiated if the speed actual value is oscillating and the speed controller output repeatedly goes to its limit. p. 298

What to do

  1. ['• Check whether the servo motor can rotate freely or not.\n• Check the torque limit.\n• Check the inversion of the actual value.\n• Check the motor encoder connection.\n• Check the encoder pulse number.'] p. 298

Before you service the product, read the safety instructions in the manual p. 2.

If F7900 is still not resolved

  • Contact service / dealer for assistance p. 2
    “Qualified Personnel The product/system described in this documentation may be operated only by personnel qualified for the specific task in accordance with the relevant documentation, in particular its warning notices and safety instructions.”
  • Contact service / dealer for assistance p. 13
    “NOTICE Property damage due to loose power connections Insufficient tightening torques or vibration can result in loose power connections. This can result in damage due to fire, device defects or malfunctions.”
Open the manual at page 298 All SINAMICS V90, SIMOTICS S-1FL6 error codes Manual details & download

This page summarises what the manufacturer’s manual says about F7900; each statement links to the page it comes from, and quoted lines are copied word for word. It is not a substitute for the manual or for a qualified installer. ManualLib is not affiliated with Siemens. Found a mistake? Report an error.