Lenze MC1000 Series - Manual (Page 51)

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If an attempt is made to decelerate a high-inertia load too quickly, the motor will
regenerate voltage back into the drive. This will cause the DC bus voltage to rise,
which can result in a HI VOLTS fault. In order to prevent faulting, the drive will enter
DECEL FREEZE, which halts the deceleration until the DC bus voltage returns to
a normal level. The drive will then begin to decelerate again, and if necessary, will
enter DECEL FREEZE repeatedly to avoid faulting. If a very short deceleration time
is programmed, DECEL FREEZE may not be able to compensate fast enough,
resulting in a HI VOLTS fault.
In applications where very short deceleration times are required on high-inertia
loads, dynamic braking may be required. Consult the factory for more information
on the Dynamic Braking option.
10
MIN FRQ (MINIMUM FREQUENCY)
This parameter defines the lower limit of the drive’s speed range. MIN FRQ is used
in conjunction with MAX FRQ (Parameter 11 below) to define the operating range
of the drive.
If MIN FRQ is set to a value above 0.0 Hz, the drive will ramp up from 0.0 Hz when
given a start command. Once running, however, the drive will not operate below
the MIN FRQ setting unless the rotation is changed, or a stop command is issued
and the drive is programmed to ramp to a stop.
If the MINIMUM FREQUENCY is set to 0.0 Hz, the drive may be operated in ZERO
SPEED mode (drive is in RUN state, but there is no output to the motor). ZERO
SPEED operation can be used in applications requiring the ability to start and stop
the drive using only the selected speed reference. The drive will start when the
speed reference is raised above 0 VDC or 4 mA, and it will stop when the reference
is lowered to 0 VDC or 4 mA. Note that the drive must be initially started using one
of the normal start commands (keypad or terminal strip).
11
MAX FRQ (MAXIMUM FREQUENCY)
This parameter defines the upper limit of the drive’s speed range. MAX FRQ is
used in conjunction with MIN FRQ (Parameter 10 above) to define the operating
range of the drive.
WARNING!
Consult motor manufacturer before operating motor above rated
frequency. Overspeeding the motor and/or driven equipment can cause
damage to equipment and injury to personnel!
NOTE: If the drive is equipped with the High Frequency Output option, the range of
adjustment will be 1.00 - 650.0 Hz.