B3: Speed Search - YASKAWA P1000 Technical Manual

n b2-01: DC Injection Braking Start Frequency
Active when "Ramp to Stop" is selected as the stopping method (b1-03 = 0).
No.
b2-01
V/f Control
Sets the starting frequency for DC Injection Braking at Stop. When the output frequency falls below the setting of b2-01, DC
Injection Braking is enabled for the time set in parameter b2-04.
Note: If b2-01 is set to a smaller value than E1-09 (Minimum Frequency), then DC Injection Braking will begin when the frequency falls to the
E1-09 value.
n b2-02: DC Injection Braking Current
Sets the DC Injection Braking current as a percentage of the drive rated current. The carrier frequency is automatically reduced
to 1 kHz when this parameter is set to more than 50%.
No.
b2-02
n b2-03: DC Injection Braking Time at Start
Sets DC Injection Braking time at start. Disabled when set to 0.00 s.
No.
b2-03
n b2-04: DC Injection Braking Time at Stop
Sets DC Injection Braking time at stop.
No.
b2-04
u

b3: Speed Search

The Speed Search function allows the drive to detect the speed of a rotating motor shaft that is driven by external forces and
start the motor operation directly from the detected speed without first stopping the machine.
Example: When a momentary loss of power occurs, the drive output shuts off and the motor coasts. When power returns, the
drive can find the speed of the coasting motor and restart it directly.
For induction motors, the drive offers two types of Speed Search than can be selected by parameter b3-24 (Speed Estimation
and Current Detection). Both methods are explained below and followed by a description of all relevant parameters.
n Current Detection Speed Search (b3-24 = 0)
Current Detection Speed Search detects the motor speed by looking at motor current in IM motors. When Speed Search is
started it reduces the output frequency starting from either the maximum output frequency or the frequency reference while
increasing the output voltage using the time set in parameter L2-04. As long as the current is higher than the level set to b3-02,
the output frequency is lowered using the time constant set to b3-03. If the current falls below b3-02, the drive assumes that
the output frequency and motor speed are the same and accelerates or decelerates to the frequency reference.
Be aware that sudden acceleration may occur when using this method of Speed Search with relatively light loads.
Figure 5.9 illustrates Current Detection Speed Search operation after a momentary power loss (L2-01 must be set to 1 or 2):
YASKAWA SIEP YAIP1U 01C AC Drive - P1000 Technical Manual
Name
DC Injection Braking Start Frequency
E1-09 Min. Output Freq.
b2-01 DC Inj. Braking Start Freq.
Output
Frequency
Figure 5.8 DC Injection Braking at Stop for V/f
Name
DC Injection Braking Current
Name
DC Injection Braking Time at Start
Name
DC Injection Braking Time at Stop
Setting Range
0.0 to 10.0 Hz
DC Injection
Braking
Time
b2-04
Setting Range
0 to 100%
Setting Range
0.00 to 10.00 s
Setting Range
0.00 to 10.00 s
5.2 b: Application
Default
0.5 Hz
Default
50%
Default
0.00 s
Default
0.50 s
5
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