LEESON Micro Series Compact Inverters - Manual (Page 55)

Example: The critical frequency is 21 Hz, and a bandwidth of 2 Hz is desired. Therefore, set SKIP #1 to 20
Hz and set SKIP BANDWIDTH to 2 Hz. This results in a speed range from 20 Hz to 22 Hz that the drive
will not operate within continuously. If the drive were operating at 25 Hz and then commanded to operate
at a speed within the range of avoidance, the drive would decelerate to 22 Hz and remain at that frequency
until commanded to 20 Hz or below. The drive would then decelerate through the range of avoidance to
the new frequency. Likewise, if the drive were operating at 18 Hz, and then commanded to operate at a
speed within the range of avoidance, the drive would accelerate to 20 Hz and remain at that frequency until
commanded to a speed of 22 Hz or above. The drive would then accelerate through the range of avoidance
to the new frequency.
8 ACCEL (ACCELERATION TIME)
ACCEL sets the acceleration rate for all speed reference sources (keypad, speed pot, 4-20 mA, 0-10
VDC, jog, and the preset speeds). The ACCEL setting is the time to accelerate from 0 Hz to the BASE
FREQUENCY (Parameter 18). The range of adjustment for ACCEL depends on horsepower. Refer to the
table below:
Example: If ACCEL is set to 30 seconds, and the BASE FREQUENCY is set for 60 Hz, the drive will ramp
from 0 Hz to 60 Hz in 30 seconds. This is a linear function, therefore the drive would ramp up to 30 Hz
in 15 seconds, etc .
NOTE: The ability to accelerate a given load at a particular rate will be limited by the output power
capability of the drive/motor combination . The acceleration of high-inertia and high-friction loads may
be affected by the current limiting characteristics of the drive . See Parameters: 16 - CURRENT, 19 - FX
BOOST, and 20 - AC BOOST for more information .
9 DECEL (DECELERATION TIME)
This parameter sets the deceleration rate for all speed reference sources . The DECEL setting indicates time
to decelerate from BASE FREQUENCY to 0 Hz. As with Parameter 8 - ACCEL, this is a linear function.
If the drive is set to COAST to stop, this parameter will have no effect when a STOP command is given .
The range of adjustment for DECEL depends on the horsepower and voltage rating, and whether Dynamic
Braking is being used. Refer to the table on next page:
53
ACCELERATION LIMITS
120 - 240 Vac 400 - 590 Vac RANGE OF
MODELS MODELS ADJUSTMENT
0 .25 - 20 HP 1 - 20 HP 0 .1 - 3600 SEC
25 - 30 HP 25 - 60 HP 0 .3 - 3600 SEC
— 75 - 150 HP 1 .0 - 3600 SEC