SINUS-K
PROGRAMMING
MANUAL
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3.7.
TORQUE CONTROL (VTC SW only)
Vector control allows the torque control of an asynchronous motor.
Set parameter C15 (command) as Torque. The value of the main reference corresponds to the torque needed by the
motor ranging from 0 to 100% of the max. torque value set through parameter C42 (Running Torque). Parameter C42
is expressed as a percentage of the motor rated torque.
For example, using an inverter SINUS K 0020 connected to a 15kW motor, C42 factory setting is equal to 120% of the
motor rated torque. This means that with 10V to terminal 2 (C14 = TERM), the torque reference is equal to 120%.
If a 7.5kW motor is connected to the inverter, parameter C42 may be increased over 200%; with respect to the value
set in C42, a torque higher than 200% may be obtained.
The motor rated torque is calculated as follows:
C=P/
ω
where P is the rated power expressed in W and
ω
is the rated speed of rotation expressed in radiant/sec.
Example: a 15kW motor at 1420RPM has a rated torque equal to:
15000
C = –––––––––––– = 100.9 Nm
1420
⋅
2
π
/60
In that case, the starting torque will be equal to
rated torque * 120% = 121.1 Nm
3.8.
POWER DOWN
In case of mains failure, it is possible to keep the inverter running by exploiting the kinetic energy of the motor and
load: energy recovered during the motor slowing down is used to supply power to the inverter, thus avoiding loosing
control due to a mains black–out.
All parameters relating to this function are included in the Power Down submenu (Configuration menu).
The following options may be selected through parameter C35 (SW IFD) or C32 (SW VTC):
– [NO]:
the function is disabled (factory setting);
– [YES]:
once a time period set through parameter C36 (Power Delay time) is
over, a deceleration ramp takes place. Its duration may be programmed through C37 (PD
Dec. Time);
– [YES V] (VTC SW only): in case of mains failure for a time longer than the value set in C36, power down is performed
and DC voltage in the DC link is kept constant at the value set in C33. This is done through
a PI regulator (proportional–integral regulator) adjusted through two parameters:
proportional (C34) and integral (C35).
NOTE
Power down may be performed only if the ENABLE command and START command are
active.
