Mitsubishi Electric · Mitsubishi FR-E800 Variable Frequency Drive
During torque control under Real sensorless vector control, if the speed command and estimated speed directions differ when reversing, the motor may not decelerate correctly at low speeds. This leads to an overload condition, shutting off the inverter output. This protective function is specific to Real sensorless vector control and prevents motor overcurrents.
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Perform an autotuning procedure (e.g., using Pr.96 and Pr.99 with Pr.1100 set to 1) to accurately identify motor parameters.
Review and adjust deceleration time parameters (e.g., Pr.7 Deceleration time) to allow for sufficient time for speed reversal.
Increase Pr.18 (Torque boost) or Pr.823 (Motor speed at which boost starts) to provide more low-speed torque during deceleration.
Verify mechanical load and ensure there is no excessive friction or external braking preventing smooth deceleration.
If operating at very low speeds, consider adding an encoder feedback option for more precise speed control instead of sensorless vector.