Specifications

NOTE 2: This parameter can be set as low as the value shown in the WITH DB column.

However, the value shown in the WITHOUT DB column is the operational limit of a drive

without dynamic braking. For example, DECEL can be set as low as 0.1 seconds on a 10

HP, 480 Vac drive without dynamic braking, but the actual minimum 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).