B3: Speed Search - YASKAWA GA700 Technical Manual

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b2-13: Short Circuit Brake Time @ Start
No.
Name
(Hex.)
b2-13 Short Circuit Brake
Time @ Start
(01BB)
This function is used to fully stop a PM motor with a large inertia during deceleration, and prevent the inertia
from causing the motor to continue rotating.
Short Circuit Braking operates for the time set in b2-13 when output frequency falls below either the value set in
b2-01 [DC Injection/Zero SpeedThreshold] or E1-09 [Minimum Output Frequency].
A setting of 0.00 disables this function.
Note:
It may be necessary to install a dynamic braking option to the drive, depending on motor speed and load conditions.
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b2-18: Short Circuit Braking Current
No.
Name
(Hex.)
b2-18 Short Circuit Braking
Current
(0177)
The Short Circuit Braking current cannot be higher than the drive rated current, although a higher current level
can be set using b2-18. The maximum rated current is 120% when the drive is set for Normal Duty (C6-01 = 1
[Normal Duty Rating]). The maximum rated current is 150% when the drive is set for Heavy Duty (C6-01 = 0
[Heavy Duty Rating]).
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b3: Speed Search

The Speed Search function detects the actual speed of a coasting motor, then restarts the motor without stopping
it. Speed Search is used in the following situations.
• Continuing operation after momentary power loss
• Switching from commercial power supply to the drive
• Restarting a coasting fan
For example, the drive output shuts off and the motor coasts when a momentary loss of power occurs. Once power
is restored, the drive performs Speed Search on the coasting motor, and then restarts the motor from the speed it
detected.
Be sure to enable b3-01 [Speed Search Selection at Start] when using a PM motor.
There are two types of Speed Search for induction motors: Current Detection and Speed Estimation. Select the
type of Speed Search with parameter b3-24 [Speed Search Method Selection].
Parameter settings vary depending on the type of Speed Search. Refer to the following table.
Parameters
b3-01 [Speed Search Selection at Start]
b3-03 [Speed Search Deceleration Time]
b3-05 [Speed Search Delay Time]
b3-06 [Speed Estimation Current Level 1]
b3-07 [Speed Estimation Current Level 2]
b3-08 [Speed Estimation ACR P Gain]
b3-09 [Speed Estimation ACR I Time]
b3-10 [Speed Estimation Detection Gain]
b3-14 [Bi-Direction Speed Search Select]
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
V/f CL-V/f OLV CLV AOLV
Sets the Short Circuit Braking time at stop.
V/f CL-V/f OLV CLV AOLV
Sets the Short Circuit Braking current as a percentage of the motor rated
current.
Table 11.21 Speed Search and Related Parameters
Current Detection 2
x
x
x
-
-
-
-
-
-
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
11.3 b: Application
Default Setting
(Range)
A1-02 = 8: 0.00 s
Other than A1-02 =
8: 0.50 s
(0.00 - 25.50 s)
Default Setting
(Range)
100.0%
(0.0 - 200.0%)
Speed Estimation
x
-
x
x
x
x
x
x
x
607
11