B3: Speed Search - YASKAWA FSDrive-MV1000 Parameter Manual

b2-02: DC Injection Braking Current
■
Sets the DC Injection Braking current as a percentage of the drive rated current. If set larger than 50%, the carrier
frequency is automatically reduced to 1 kHz.
No.
b2-02
The level of DC Injection Braking current affects the strength of the magnetic field attempting to lock the motor shaft.
Increasing the current level will increase the amount of heat generated by the motor windings. This parameter should
only be increased to the level necessary to hold the motor shaft.
b2-03: DC Injection Braking Time at Start
■
Sets the time of DC Injection Braking (Zero Speed Control when in CLV) at start. Used to stop a coasting motor before
restarting it or to apply braking torque at start. Disabled when set to 0.00 s.
No.
b2-03
Note: Before starting an uncontrolled rotating motor (e.g., a fan motor driven by windmill effect), DC Injection or Speed Search should
be used to either stop the motor or detect its speed before starting it. Otherwise motor stalling and other faults can occur.
b2-04: DC Injection Braking Time at Stop
■
Sets the time of DC Injection Braking (Zero Speed Control when in CLV) at stop. Used to completely stop a motor with
high inertia load after ramp down. Increase the value if the motor still coasts due to inertia after it should have stopped.
Disabled when set to 0.00 s.
No.
b2-04
<1> For details on the default settings, refer to
b2-08: Magnetic Flux Compensation Value
■
Parameter b2-08 sets the magnetic flux compensation at start as a percentage of the no-load current value (E2-03). This
function allows more flux to develop, making it easier to start machines that require high starting torque or motors with a
large rotor time constant.
No.
b2-08
When a Run command is issued, the DC current level injected into the motor changes linearly from the level set in b2-08
to E2-03 within the time set to b2-03.
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 in 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.

◆ 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
(e.g., a fan rotating by windmill effect or a motor driven by load inertia). Motor operation can be started directly from the
speed detected without needing to stop the machine before.
Example: When a momentary loss of power occurs, the drive output shuts off. This results in a coasting motor. When
power returns, the drive can find the speed of the coasting motor and restart it directly.
YASKAWA ELECTRIC EZZ010930 FSDrive-MV1000 Parameter Guide
Name
DC Injection Braking Current
Name
DC Injection Braking Time at Start
Name
DC Injection Braking Time at Stop
Control Mode Dependent Parameter Default Values on page
Name
Magnetic Flux Compensation Value
Setting Range
0 to 100% 50%
Setting Range
0.00 to 10.00 s 0.00 s
Setting Range
0.00 to 10.00 s Determined by A1-02
79.
Setting Range
0 to 1000% 0%
2.2 b: Application
Default
Default
Default
<1>
Default
103