YASKAWA U1000 Technical Manual page 198

5.2 b: Application
After restoring power, the Speed Search operation remains in baseblock status for at least the time set in b3-05. However,
Speed Search will not start if the time set in L2-03, Minimum Baseblock Time, does not pass after the power stops. When
induced voltage remains in the motor, the Speed Search operation starts after the time set in b3-05 without waiting for the time
set in L2-03.
Figure 5.17 Timing Chart for Speed Search after Recovery from Momentary Power Loss
When performing a speed search operation at start, the speed search operation will start after waiting for the longer of the
times set in b3-05 and L2-03 after the Run command input is received. When induced voltage remains in the motor, the Speed
Search operation starts after the time set in b3-05 without waiting for the time set in L2-03.
n Current Detection Speed Search 2 (b3-24 = 2)
Current Detection Speed Search 2 is for use with IM motors. The current set in b3-31 is applied and the speed is detected
based on the current flow to the motor. The speed then accelerates or decelerates to the frequency reference after completing
Speed Search. If the output current during the Speed Search operation is larger than the setting value of b3-32, reduce the
frequency for the deceleration time set in b3-03. After motor speed estimation is completed, the speed is accelerated or
decelerated to the frequency reference.
n Current Detection Speed Search 3 (b3-24 = 4)
Current Detection Speed Search 3 applies the current set in b3-31 and detects the speed based on the current flow to the motor.
The speed then accelerates or decelerates to the frequency reference after completing Speed Search.
Reduce the frequency for the deceleration time set in b3-03 if the output current during the Speed Search operation > b3-32.
The speed then accelerates or decelerates to the frequency reference after completing motor speed estimation.
b3-14 sets how the drive determines the motor rotation direction when performing Speed Estimation Speed Search:
• The drive uses the frequency reference to determine the direction of motor rotation in order to restart the motor.
• The drive detects the motor rotation direction in order to restart the motor.
n Speed Estimation Speed Search (b3-24 = 1)
A Speed Estimation Speed Search estimates the motor speed while the motor is coasting and then restarts operation. The speed
then accelerates or decelerates to the frequency reference after completing Speed Search.
This method can be used for a single induction motor connected to a drive. Do not use this method if the motor is one or more
frame size smaller than the drive, at motor speeds above 200 Hz, or when using a single drive to operate more than one motor.
198
AC Power supply
Output frequency
Minimum Baseblock Time (L2-03)
Run command
Output
frequency
Figure 5.18 Timing Chart for Speed Search at Start
YASKAWA ELECTRIC SIEP C710636 04D U1000 Industrial MATRIX Drive Technical Manual
b3-05
Minimum Baseblock
Time (L2-03)
b3-05