
Advanced Operation
7.3.1 Application Constants: b
- 20
J
Speed Search: b3-01 to b3-03
The speed search function finds the speed of a coasting motor and starts up smoothly from that speed. It
is effective in situations such as switching from a commercial power supply.
Speed Search Selection at Start: b3-01
User
Change
during
Setting
Factory
Valid Access Levels
User
Constant
Number
Name
during
Opera-
tion
Setting
Range
Unit
Factory
Setting
Open Loop
Vector
Flux Vector
b3-01
Speed search selection
at start
0 1
--
0 *
A
A
*
When the control method is switched, the factory setting changes as follows:
open-loop vector 0; flux vector: 1
D
Settings
Setting
Contents
0
Speed search disabled:
Motor starts from minimum output frequency.
1
Speed search enabled:
Speed search is performed from maximum output frequency and
motor is started. (In control methods with PG, i.e., V/f with PG feed-
back and flux vector, motor starts from the motor speed.)
D
Set “1” to use the speed search function. A speed search is performed each time the run command is
input.
D
To use speed search freely in control methods without PG, i.e., V/f control and open-loop vector con-
trol, set the multi-function contact input selection (H1-01 to H1-06) to 61 or 62 (external search com-
mand). (See para 7.3.5.)
Speed Search Operating Current, Speed Search Deceleration Time, and Min. Baseblock Time:
b3-02, b3-03, L2-03
User
Change
during
Setting
Factory
Valid Access Levels
User
Constant
Number
Name
during
Opera-
tion
Setting
Range
Unit
Factory
Setting
Open Loop
Vector
Flux Vector
b3-02
Speed search operating
current
0
200
%
100
A
b3-03
Speed search decelera-
tion time
0.1
10.0
s
2.0
A
L2-03
Min. baseblock time
0.0
0.5
s
0.5
*
B
B
*
The factory setting varies depending on the Inverter capacity. The values shown in the table
are for 200 V class Inverters of 0.4 kW.
D
For the speed search operating current (b3-02), set the operating current for the speed search. If restart-
ing is not possible with the setting, then lower the setting.
D
Set the speed search operating current as a percentage of the Inverter’s rated output current, with the
Inverter’s rated output current taken as 100%.
D
For the speed search deceleration time (b3-03), set the output frequency deceleration time for while
the speed search is being performed. Set the time required to decelerate from the maximum output fre-
quency to 0 Hz.
D
Speed search deceleration (b3-03) can be used for the Speed search after winding change.
D
When the speed search and DC injection braking are set, set the minimum baseblock time (L2-03). For
the minimum baseblock time, set the time to wait for the motor’s residual voltage to dissipate. If an
overcurrent is detected when starting a speed search or DC injection braking, raise the setting to pre-
vent a fault from occurring.
Run command
OFF
ON
Maximum output
frequency
Deceleration time set for b3-03
Frequency
reference
that is set
Output frequency
Minimum baseblock time (L2-03)
b3-02
Output current
Fig
7.10
Speed Search Timing Chart
7