52
NOTE 1: 240/120 Vac units have the same limits as 240/200 Vac units.
NOTE 2: The parameter value can be set below the minimum value shown, but
the value shown is the operational limit of the drive. For example, if DECEL is set
for 0.1 seconds on a 10 HP, 480 Vac drive without dynamic braking, the actual
deceleration time would be 0.5 seconds.
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.
To Next Page
Loading...
