YASKAWA OYMC V1000, Programming Manual

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1.2 b: Application
YASKAWA ELECTRIC SIEP C710606 10A YASKAWA AC Drive - V1000 PRELIM. Programming Manual 51
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Figure 1.13
Figure 1.13 Speed Search after Baseblock
* 1. Once AC power is restored, the drive will wait for at least the time set to b3-05. If the power
interruption is longer than the Minimum Baseblock Time L2-03, the drive will wait for b3-05 after the
power has returned before starting Speed Search.
Current Injection
This method is used when there is no detectable back EMF, e.g. after longer power losses,
when Speed Search is applied with the Run command (b3-01 = 1) or if an External Search
command is used. It injects the DC current set in b3-06 to the motor and detects the speed by
measuring the current feedback. The drive outputs the detected frequency and increases the
voltage using the time constant set in parameter L2-04. If the resulting current is higher than
the level in b3-02 the output frequency is reduced. When the current becomes lower than b3-
02 the motor speed is assumed to be found and the drive starts to accelerate or decelerate to
the frequency reference.
AC power
supply
Output
frequency
Output
current
OFF ON
Starts at the speed
that was detected
Selected
frequency
reference
Min. Baseblock Time
(L2-03)
Several miliseconds
b3-05*1