VFD’S common problems troubleshooting solutions (L&T DRIVE)


The motor does not rotate and outputs current is too high at start

Solutions: Causes- The load is too high.it can be solved by using manual/auto torque boost and changing some parameter

  1. Manual Torque Boost: Slightly increase the forward or reverse boost in dr-16 or dr 17 (L&T drive). if the torque boost level is too high a trip may occur such as IOL ERROR MESSAGE.
  2. Auto Torque Boost(ATB): SET dr-15 to1 and then adjust the values in dr-26-28.
  3. Start Frequency: increase the start frequency in dr-19 (ex. 0.5→1.0→1.5→2.0hz).
  4. User V/f Pattern: when bA→07 is set to 2, user V/f pattern can be set according to the application and motor characteristics

There is a disturbing humming sound at the motor

Solutions: Causes:- increase or decrease the carrier frequency in Cn-04

When the drive is running my earth leakage circuit breaker (ELCB) trips.

Solutions: Causes: ELCB Will disconnect the power if leakage current flow to grounding during drive operation

  1. Solutions: connect the drive to a ground terminal.
  2. Solutions: check if ground resistance is less than 100 Ω to 200 V class.
  3. Solutions: check the capacity of ELCB connect it to the drive according to the rated current of the drive
  4. Solutions: reduce the carrier frequency in Cn-04
  5. Solutions: Attempt to keep the cable distance from the drive to motor short as possible

How do I Reset the drive back to factory default settings?

Solutions: Set dr-93 to 1(All group) and press the enter X2. Dr-93 is displayed again when the initialization has been completed

How do I adjust the time it takes the motor to speed up and down.

Solutions: Adjust the acceleration time in ACC and Deceleration time dEC.

How do I prevent the drive from tripping on an OV Fault (over-voltage)while the motor is ramping down?

Solutions-1: Increase the declaration time in dEC

Solutions-2: Activate flux braking in Pr-50. Activating the very first bit on the left

Solutions-3: A DB Resistor may be installed due to the characteristics of the load

How to drive preventing overload Fault?

Solutions-: Verify motor rated current in bA-13 & motor overload parameter setting Pr-20(overload trip selection), Pr-21(overload trip level) and Pr-22(overload trip time)





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Author: yawot

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