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5.2 b: Application
192
YASKAWA ELECTRIC
SIEP C710636 02B YASKAWA U1000 Technical Manual
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b2-04: DC Injection Braking Time at Stop
Sets the time of DC Injection Braking (Zero Speed Control when in CLV and CLV/PM) at stop. Used to completely stop
a motor with high inertia load after ramp down. Increase the value if the motor still coasts by inertia after it should have
stopped. Disabled when set to 0.00 s.
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b2-08: Magnetic Flux Compensation Value
Sets the magnetic flux compensation at start as a percentage of the no-load current value (E2-03). This function allows
better more flux to develop, making it easier to start machines that require high starting torque or motors with a large
rotor time constant.
When a Run command is issued, the DC current level injected into the motor changes linearly from the level set to b2-08
to E2-03 within the time set to b2-03.
If b2-08 is set to a value other than 0%, the current will flow at the time that is set to b2-03 (DC Injection Braking Time
at Start) when DC Injection Braking starts. The current will change linearly from the setting in b2-08 to the setting in
E2-03. Note that the level of the DC current injected to the motor is limited to 80% of the drive rated current or to the
motor rated current, whichever value is smaller.
Note: 1.
If b2-08 is set below 100%, it can take a relatively long time for flux to develop.
2.
If b2-08 is set to 0%, the DC current level will be the DC Injection current set to b2-02.
3.
As DC Injection can generate a fair amount of noise, b2-08 may need to be adjusted to keep noise levels acceptable.
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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.
Enabling Speed Search for PM motors only requires setting parameter b3-01 to 1. The drive offers current detection and
speed estimation Speed Search for induction motors. Parameter b3-24 selects the speed search method for induction
motors. Both methods and relevant parameters are explained below.
Speed Search start timing differs depending on whether operation is after a momentary power loss (L2-01 = 1 or 2) or
after the Speed Search at start (b3-01 = 1).
The operation timing of the Speed Search after a momentary power loss is shown in
. The operation timing
after the Speed Search at start is shown in
.
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, has not expired 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.
No.
Name
Setting Range
Default
b2-04
DC Injection Braking Time at Stop
0.00 to 10.00 s
Determined by A1-02
No.
Name
Setting Range
Default
b2-08
Magnetic Flux Compensation Value
0 to 1000%
0%
SIEP_C710636_02B_1_0.book 192 ページ 2015年11月25日 水曜日 午後4時56分