Diagnostics And Fault Elimination; Malfunctions - Lenze MCM Series Mounting And Switch-On Instructions

Diagnostics and fault elimination

Malfunctions

If faults occur during the operation of the drive system, the table below helps you to identify
the causes. If it is not possible to remedy the fault using the measures listed, please contact
the Lenze aftersales service department.
Fault
Motor too hot
Can only be evaluated by measuring the surface
temperature:
• Non‐ventilated motors >140 °C
• Externally ventilated or self‐ventilated motors
> 110 °C
Motor suddenly stops and does not restart
Incorrect direction of rotation of the motor,
correct display on the inverter
Motor rotates normally but does not reach the
expected torque
Motor turns in one direction at maximum speed
in an uncontrolled manner
Motor slowly rotates in one direction and is not
influenced by the inverter
Irregular running
Vibrations
Running noises
Surface temperature > 140 °C
Diagnostics and fault elimination
Possible causes
Insufficient cooling air, blocked air ducts.
Preheated cooling air
Overload, with normal mains voltage the
current is too high and the speed too low
Rated operating mode (S1 to S8 IEC/EN
60034-1) exceeded
Loose contact in supply cable (temporary
single-phase operation!)
Fuse has blown (single-phasing!)
Overload of the drive
Heat dissipation impeded by deposits
Overload monitoring of the inverter is activated Check inverter settings
Motor cable with reverse polarity
Polarity of encoder cable reversed
Motor cable interchanged cyclically
Not all motor phases connected
Motor cable interchanged cyclically
Polarity of encoder cable reversed
Polarity of motor cable and encoder cable
reversed
Insufficient shielding of motor or resolver cable Checking shielding and earth connection
Inverter gain too large
Insufficiently balanced coupling elements or
machine
Inadequate alignment of drive train
Loose fixing screws
Foreign particles inside the motor
Bearing damage
Overload of the drive
Heat dissipation impeded by deposits
Malfunctions
Remedy
Ensure unimpeded circulation of cooling air
Ensure a sufficient supply of fresh cooling air
Use larger drive (determined by power
measurement)
Adjust rated operating mode to the specified
operating conditions. Determination of correct
drive by expert or Lenze customer service
Tighten loose contact
Replace fuse
Check load and, if necessary, reduce by means
of longer ramp-up times
Check winding temperature
Clean surface and cooling fins of the drives
Reduce load caused by longer acceleration
times
Check and correct polarity
Connect the phases at the motor cable
connection correctly
Check motor connector and, if necessary,
correct
Check encoder connection and, if necessary,
correct
Check and correct polarity
Adjust the gains of the controllers (see
operating instructions for the inverter)
Rebalance
Realign machine unit, check foundation, if
necessary.
Check and tighten screw connections
Repair by the manufacturer, if necessary
Check load and, if necessary, reduce by means
of longer ramp-up times.
Check winding temperature
Clean surface and cooling fins of the drives.
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