No. Name Setting Range Default
b3-24 Speed Search Method Selection
0: Current Detection Speed Search
1: Speed Estimation Type Speed Search
0
L2-01 Momentary Power Loss Operation Selection
0: Disabled - Drive trips on (UV1) fault when power is lost.
1: Power Loss Ride-Thru Time - Drive will restart if power returns within the time
set in L2-02.
2: CPU Power Active - Drive will restart if power returns prior to control power
supply shut down.
0
The table below lists the Speed Search methods available.
Speed Search Method Speed Estimation (b3-01=2, 3) Current Detection (b3-01=0, 1)
Search Method
Estimates motor speed, then accelerates from that speed up to the specified
frequency. Works for both forwards and reverse rotation.
Outputs the frequency when momentary power loss occurs, as well as the maximum
frequency and the frequency reference. Caculates the current level relative to those
values when Speed Search begins.
External Speed Search
Both External Speed Search 1 and 2 perform the same action, estimating
the speed of the motor and then searching for the speed based on that
estimated value.
External Speed Search 1: Searches for the speed based on the maximum output
frequency.
External Speed Search 2: Searches for the motor speed based on the most recent
frequency reference.
Application Notes
Not for use when running multiple motors from a single drive or when the
drive is a frame size larger than the motor. Cannot be used at speeds greater
than 130 Hz.
Sudden acceleration may occur with relatively light loads.
Multi-Function Input Selections (H1-01 to H1-07)
Setting Description
61 External Search Command 1 Closed: Executes Speed Search from the maximum output frequency (E1-04).
62 External Search Command 2 Closed: Executes Speed Search from the frequency reference.
Detailed Description
Speed Estimation (b3-24 = 1)
In Speed Estimation, the drive first estimates the speed of the motor, then accelerates (or decelerates) to that frequency. To enable Speed Estimation at
start, set b3-24 to “1”. To also allow Speed Estimation in reverse, set b3-26 to “1”.
Note: Perform Auto-Tuning before using Speed Estimation Speed Search. Perform Auto-Tuning again if the there is change in the cable length between the drive and motor. Speed
Estimation should not be used to search for speeds beyond 130 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. Yaskawa recommends using Current Detection Speed Search instead. Speed Estimation may have trouble finding the actual speed if the motor
cable is longer than 50 m. We recommend using Current Detection Speed Search in such situations. Use Current Detection Speed Search instead of Speed Estimation when
operating motors small than 0.75 kW. Speed Estimation can end up stopping smaller motors as it attempts to find the speed or figure out what direction the motor is rotating
in. When using PM Open Loop Vector Control along with a fairly long motor cable, Yaskawa recommends using Short Circuit Braking instead of Speed Estimation. If attempting
to find the speed of a motor coasting faster than 120 Hz when using PM Open Loop Vector Control, Yaskawa recommends using Short Circuit Braking instead of Speed
Estimation. shows how the drive operates when performing Speed Search to start the motor and when an external Speed Search command is given via the multi-function input
terminals.
Speed Search at Start (b3-24 = 1)
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)*
Figure 5.9 Speed Search at Start
*The wait time for Speed Search (b3-05) determines the lower limit.
Note: If the run command is quickly switched off and then back on again when the drive is set to coast to stop following a stop command, Speed Search will operate as shown in the
second diagram.
The timechart below demonstrates how the drive operates when power is restored after a momentary power loss.
5.2 b: Setup
118
YASKAWA ELECTRIC SIEP C710606 18A YASKAWA AC Drive – V1000 Technical Manual (Preliminary)
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