Yaskawa Z1000U HVAC Matrix Bypass - Manual (Page 136)

Output
frequency
Time
b2-04
DC Injection
Braking
E1-09 Min. Frequency
b2-01 Zero Speed Level
Figure 5.6 DC Injection Braking at Stop for V/f
Note: If b2-01 is set to a smaller value than parameter E1-09 (minimum frequency), then DC Injection Braking will begin as soon as the frequency
falls to the value set to E1-09.
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. Name Setting Range Default
b2-02 DC Injection Braking Current 0 to 100% 50%
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. Do not set this parameter higher
than the level necessary to hold the motor shaft.
n b2-03: DC Injection Braking Time at Start
Sets the time of DC Injection Braking 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. Name Setting Range Default
b2-03 DC Injection Braking Time at Start 0.00 to 10.00 s 0.00 s
Note: Before starting an uncontrolled rotating motor (e.g., a fan motor driven by windmill effect), use DC Injection or Speed Search to stop the
motor or detect motor speed before starting it. Otherwise, motor stalling and other faults can occur.
n b2-04: DC Injection Braking Time at Stop
Sets the time of DC Injection Braking 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.
No. Name Setting Range Default
b2-04 DC Injection Braking Time at Stop 0.00 to 10.00 s 0.00 s
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 that can be selected by parameter b3-24 (Speed Estimation
and Current Detection). Both methods are explained below and followed by a description of relevant parameters.
n Speed Search Activation
Speed Search can be activated using any of the methods 1 through 5 described below. The Speed Search type must be selected
in parameter b3-24 independent of the activation method.
Method 1. Automatically activate Speed Search with every Run command. External Speed Search commands are ignored.
Method 2. Activate Speed Search using the digital input terminals.
Use the input functions for H1-oo in
Table 5.1 .
5.2 b: Application
136 YASKAWA SIEP YAIZ1D 01A Z1000U HVAC MATRIX Drive Bypass Technical Manual