LEESON SM-Basic Series Sub-Micro Inverters (Obsolete) - Manual (Page 36)

32
2 8 FIXED BOOST
FIXED BOOST increases starting torque by increasing the output voltage when operating below half
of the base frequency, which increases the V/Hz ratio. For better out-of-the-box performance, SCN
Series drives are shipped with a setting that is different from the factory default of 1%. Units rated
0.25 to 1 HP are set to 5.3%, units rated 1.5 to 2 HP are set to 4.4%, and 3 HP units are set to 3.6%.
29 ACCELERATION BOOST
ACCELERATION BOOST helps accelerate high-inertia loads. During acceleration, the output voltage
is increased to increase motor torque. Once the motor reaches the new speed setpoint, the boost is
turned off and the output voltage returns to the normal value.
30 SLIP COMPENSATION
SLIP COMPENSATION is used to counteract changes in motor speed (slip) caused by changes in
load. In a standard AC induction motor, the shaft speed decreases as load increases, and increases as
load decreases. By increasing or decreasing the output frequency in response to an increasing or
decreasing load, the slip is counteracted and speed is maintained. Most standard NEMA B motors
have a 3% slip rating.
To set this parameter, multiply the desired setting by 10 and enter that value. For example, if a
setting of 2.5% is desired, enter 25 into this parameter.
31 - 37 PRESET SPEED #1 - #7
Preset speeds are activated by contact closures between TB-11 and TB-13A, 13B, and 13C. The TB-
13 terminals must be programmed as preset speed selects using Parameters 10-12.
NOTE 1: Preset speeds can operate below the frequency defined by the minimum frequency parameter
(Parameter 23).
Refer to the table below for activation of the preset speeds using the TB-13 terminals.
SPEED # TB - 13A TB - 13B TB - 13C
1 CLOSED OPEN OPEN
2 OPEN CLOSED OPEN
3 OPEN OPEN CLOSED
4 CLOSED CLOSED OPEN
5 CLOSED OPEN CLOSED
6 OPEN CLOSED CLOSED
7 CLOSED CLOSED CLOSED