S6: Power Keb Function - YASKAWA T1000A Technical Manual

5.11 S: Functions for Textile Applications
When the Frequency Reduction Step (as calculated by the drive from the slip before KEB and S5-07, S5-08 or S5-09) is
lower than S5-11, the Minimum Frequency Reduction will be used.
Note: When using one of the control modes for a PM motor, S5-11 will disabled, regardless of what value it has been set to.
No.
S5-11
u S6: Power KEB Function
S6 parameters determine how the Power KEB type of KEB operates. Power KEB is enabled when S4-01 is set to 3. It
uses machine inertia data for determining the deceleration rate needed to keep the DC bus voltage level at the value set in
parameter S4-11.
n
S6-01: DC Bus Capacity
Enter the size of any external capacitors that have been added to the drive to S6-01.
The resulting DC bus capacity used by the drive will be L3-26 + S6-01.
No.
S6-01
n
S6-02: Motor Acceleration Time
Enter the time required for the motor the drive is running to accelerate from zero up to the maximum frequency at the
rated torque. If setting in parameter E2-11 is changed by the user or by performing Auto-Tuning, then S6-02 will
automatically be set to the motor acceleration time of a standard Yaskawa 4-pole motor.
No.
S6-02
The motor acceleration time can be calculated using the formula below.
2π × J × Nr
S6-02 =
60 × T
100
GD 2
J [Kgm 2 ] P Rated output [kW] Nr Rated speed [r/min] T
4
Use the following formula to find the rated torque.
60 × P × 10
3
T =
100
2π × Nr
n
S6-03: Load/Inertia Ratio
Enter the ratio between the inertia of the load and the inertia of the motor the drive is running. This parameter also adjusts
the functions, Stall Prevention during deceleration (L3-04 = 2), and overvoltage suppression (L3-11 = 1).
No.
S6-03
If S6-03 is set to the wrong value, a large current ripple may appear during Power KEB and during overvoltage
suppression. Problems may occur with overvoltage or undervoltage in the DC bus, and overcurrent.
The load/inertia ratio can be calculated using the following formula:
Machine inertia (excluding motor)
Load inertia ratio =
An inertia setting that is too high might have an effect, even when the drive manages to decelerate to a complete stop.
The deceleration rate might be not fast enough at the end of deceleration to keep the DC bus stable.
Adjust S6-03 while measuring the DC Bus Voltage.
260
Name
KEB Frequency Reduction Step Lower Limit
Name
DC Bus Capacity
Name
Motor Acceleration Time
Name
Load/Inertia Ratio
Rotor inertia
YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual
Setting Range
0 to 500%
Setting Range
0 to 65000 μF
Setting Range
0.001 to 10.000 s
Rated torque [Nm]
100
Setting Range
0.0 to 1000.0
Default
20%
Default
Determined by drive
capacity
Default
Determined by
o2-04, E2-11, and E5-01
Default
1, 0