3-45
•
The following diagrams show the operation of each stopping method.
a)
Deceleration to Stop
(Sn-06= 0)
Deceleration to a stop at a rate set with the selected deceleration time.
b)
Coast to Stop
(Sn-06= 1)
After the stop command is executed, run source is disregarded until the Min.
baseblock time Cn-37 has elapsed.
Run
command
Output
frequency
Dec time
DC injection
braking time
DC injection
beginning frequency
(Cn-14)
ON
OFF
The inverter output is shut off when the stop
command is input
Run
command
Output
frequency
ON
OFF
Fig. 29.
Deceleration to stop
Fig. 30.
Coast to Stop
c)
Whole Range DC Injection Braking Stop (Sn-06= 2)
Run
Comm.
O/P Freq.
DEC time
DC injection
braking time
Min. baseblock time
(Cn-37)
ON
OFF
10 %
100 %
DC injection braking
time at Run Source off
(Cn-16)
Cn-16 * 10
DC injection
braking time
O/P freq. when the stop command is input
Fig. 31.
Whole range DC Injecting Braking Stop
•
After the stop command is input and the minimum baseblock time (Cn-37) has
elapsed, DC injection braking is applied and the motor stopped.
•
The DC injection braking time depends upon the output frequency when the stop
command is input and the “DC injection time at stop” setting (Cn-16) as shown in
Fig. 31
.
•
Lengthen the minimum baseblock time (Cn-37) when an overcurrent (OC) occurs
during stopping. When the power to an induction motor is turned OFF, the counter-
electromotive force generated by the residual magnetic field in the motor can cause
an overcurrent to be detected when DC injection braking stop is applied.
