B6: Dwell Function - YASKAWA A1000 Technical Manual

5.2 b: Application
 b6: Dwell Function
The Dwell function is used to temporarily hold the frequency reference at a predefined value for a set time, then continue
accelerating or decelerating.
If used with induction motors, the Dwell function can help prevent speed loss when starting and stopping a heavy load. If
running a PM motor in V/f control, the pause in acceleration allows the PM motor rotor to align with the stator field of
the motor, thus reducing the starting current.
Figure 5.29 shows how the Dwell function works.
Note: Using the Dwell function requires that the stopping method for the drive be set to "Ramp to stop" (b1-03 = 0).
Figure 5.29

b6-01, b6-02: Dwell Reference, Dwell Time at Start
b6-01 determines the frequency that is held or the time set in b6-02 during acceleration.
No.
b6-01
b6-02
<1> In AOLV/PM and CLV/PM control modes, the setting units and range are expressed as a percent (0.0 to 100.0%) instead of in Hz.

b6-03, b6-04: Dwell Reference, Dwell Time at Stop
Parameter b6-03 determines the frequency that is held for the time set in b6-04 during deceleration.
No.
b6-03
b6-04
<1> In AOLV/PM and CLV/PM control modes, the setting units and range are expressed as a percent (0.0 to 100.0%) instead of in Hz.
 b7: Droop Control (CLV, CLV/PM)
Droop control is a function for setting the motor rated slip as required. Droop control can automatically balance the load
level between two motors that drive the same load, such as in traverse cranes applications. It must be activated in one of
the two drives that control these motors. The drive in which Droop control is activated will automatically reduce the
speed if the torque reference rises, and increase the speed if the torque reference falls again, thereby shifting the load
from one motor to the other.
Note: Disable Feed Forward (n5-01 = 0) whenever using Droop control.
Figure 5.30
Motor A runs faster than B, pulling more load
A
= 100% Load
B
= 80% Load
Droop Control increases the speed reference in
drive B accomplishing load balance
178
OFF
Run Command
Output Frequency
Figure 5.29 Dwell Function at Start and Stop
Name
Dwell Reference at Start
Dwell Time at Start
Name
Dwell Reference at Stop
Dwell Time at Stop
A
= 90% Load
f = constant
ref_A
f increase
ref_B
B
= 90% Load
Figure 5.30 Droop Control in a Traverse Application
ON OFF
b6-01
b6-03
b6-02 b6-04
Motor B runs faster than A, pulling more load
A
= 80% Load
f
ref_A
B
= 100% Load
Droop Control decreases the speed reference in
drive B accomplishing load balance
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
Setting Range
0.0 to 400.0 Hz
<1>
0.0 to 10.0 s
Setting Range
0.0 to 400.0 Hz
<1>
0.0 to 10.0 s
A
= 90% Load
= constant
f decrease
ref_B
B
= 90% Load
Default
0.0 Hz
<1>
0.0 s
Default
0.0 Hz
<1>
0.0 s