Lenze DSD - Manual (Page 458)

18 Drive dimensioning messages
18.5 Lenze motor
458
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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18.5.10 A continuous operation characteristic for inverter operation is not available
18.5.11 Motor temperature too high at switching frequency < 8 kHz
18.5.12 The limit value of xxx % of the rated torque is exceeded
Note!
There is no continuous operation characteristic for the motor if operated on an inverter.
The equivalent characteristic does not take account of restrictions on motor operation due to its ventila-
tion.
Cause Effects Possible remedies
There is no data for this self-ventilat-
ed motor.
The motor may get too hot when be-
ing operated at field frequencies
< 20 Hz.
• In case of long operations at low
speed or with high thermal utili-
sation, select a motor with forced
ventilation.
• Select a more powerful motor.
Note!
The motor selected must not be permanently operated at a switching frequency < 8 kHz.
Set a fixed switching frequency on the inverter to ensure that it is not automatically reduced.
Cause Effects Possible remedies
At low switching frequencies the
losses in the motor increase.
Motor gets too hot. • Select bigger motor.
• Set switching frequency perma-
nently to min. 8 kHz if the drive
continuously runs with a too low
switching frequency.
 Effects of low switching frequencies on the motor ( 433)
Warning!
The utilisation of the motor is xxx % of the rated torque.
If the motor is operated on an inverter with V/f control, the limit value of yyy % is exceeded.
The operation is not permissible!
Cause Effects Possible remedies
With a V/f characteristic control
without feedback and low speed
range, the motor is not magnetised
as required. The motor cannot reach
the rated torque anymore.
The hoist drive cannot hold the load. • With a rated motor power
< 7.5 kW, select a bigger motor.
• Select a control mode with feed-
back.