Yaskawa AC Drive Z1000 Bypass Technical Manual - Manual (Page 124)

This feature injects the amount of DC current set to b3-06 to the motor and detects the speed by measuring the current feedback.
The drive then outputs the detected frequency and increases the voltage using the time constant set to parameter L2-04 <1>
while looking at the motor current.
<1> Details on this function can be found in the standard Z1000 Programming Manual (SIEPC71061645) at
www.yaskawa.com.
The output frequency is reduced if the current is higher than the level in b3-02. When the current falls below b3-02, the motor
speed is assumed to be found and the drive starts to accelerate or decelerate to the frequency reference.
Run command
Output
frequency
Output
current
OFF
ON
b3-02
Starts at the speed
speed that was detected
Waits twice as long as L2-04
Frequency reference
set to the drive
Decelerates at the Speed
Search decel time set to b3-03
1.0 s
Min. Baseblock Time (L2-03) <1>
Figure 5.10 Speed Search at Start
<1> The wait time for Speed Search (b3-05) determines the lower limit.
Notes on Using Speed Estimation Speed Search
• Perform Rotational Auto-Tuning for V/f Control (T1-01 = 3) prior to using Speed Estimation in V/f Control and perform
Stationary Auto-Tuning for Line-to-Line Resistance (T1-01 = 2) again if the there is a change in the cable length between
the drive and motor.
• Use Current Detection to search for speeds beyond 200 Hz if the application is running multiple motors from the same drive
or if the motor is considerably smaller than the capacity of the drive.
• Speed Estimation may have trouble finding the actual speed if the motor cable is very long. Use Current Detection in these
instances.
• Use Current Detection instead of Speed Estimation when operating motors smaller than 1.5 kW because Speed Estimation
might not be able to detect the speed or rotation of these smaller motors, in which case Speed Estimation would stop the
motor.
n Speed Search Activation
Speed Search can be activated using any of the methods 1 through 5 described below. The Speed Search type must be selected
in parameter b3-24 independent of the activation method.
Method 1. Automatically activate Speed Search with every Run command. External Speed Search commands are ignored.
Method 2. Activate Speed Search using the digital input terminals.
Use the input functions for H1-oo in
Table 5.1 .
Table 5.1 Speed Search Activation by Digital Inputs
Setting Description b3-24 = 0 b3-24 = 1
61
External Search
Command 1
Closed: Activate Current Detection Speed Search from the
maximum output frequency (E1-04). Activate Speed Estimation
Speed Search
62
External Search
Command 2
Closed: Activate Current Detection Speed Search from the
frequency reference.
To activate Speed Search by a digital input, the input must be set together with the Run command or the Run command must
be entered after giving the Speed Search command.
Method 3. After automatic fault restart.
When the number of maximum fault restarts in parameter L5-01 is set higher than 0, the drive will automatically perform
Speed Search as specified by b3-24 following a fault.
5.2 b: Application
124 YASKAWA ELECTRIC SIEP YAIZ1B 01D YASKAWA AC Drive – Z1000 Bypass Technical Manual