Yaskawa CIMR-V7AM-091 - Manual (Page 11)

Date: 02/20/05, Rev: 05-02 Page 11 of 15 TM.V7SW.091
2.6 Timing Charts
KEB Using DC Bus Voltage Detection
When a KEB command is not set to the multi-function input, KEB starts according to the drive’s DC
bus voltage. The drive specifies the recovery from power loss when this voltage is restored after
the Power Loss Detection Relay Delay Time elapses, and re-accelerates up to the former speed.
Turn OFF the run command at a momentary power loss or when a power failure occurs if
re-acceleration is not to be made at recovery from the power loss. The following shows the chart
diagram when the run command is turned OFF.
Note: To execute re-acceleration at recovery from the power loss, maintain the run command ON
during power loss. If recovery is sometimes detected improperly, set the Power Loss Detection
Relay Delay Time (n144) to a greater value than the possible maximum momentary power loss time.
Drive main circuit
DC bus bar voltage
←Braking Transistor Operational Voltage or Deceleration
Stall Prevention Operational Voltage.(n049)
Drive Output Frequency
KEB Starting Voltage→
0
Power loss
↓
←After the under voltage detection, according to the
status of DC bus bar voltage
During under
Voltage Detection OFF
ON
During KEB
Operation
OFF
ON
0
KEB Deceleration Ratio Changeover Time (n047)
Power Loss Detection Relay Delay Time (n144)
KEB Deceleration Time 1
KEB Deceleration Time 2 (n046)
RUN(FWD)
Command
OFF
ON
(n048)
(n045)