Yaskawa CIMR-V7AM-091 - Manual (Page 7)

Date: 02/20/05, Rev: 05-02 Page 7 of 15 TM.V7SW.091
2.5 Description of Operation
Basic Operation
Setting parameter n081 (Selection of Operation after Recovery from Momentary Power Loss) to 3
(KEB Operation Continued) or setting a multi-function digital input terminal to the KEB command
(NO contact: 28, NC contact: 29) enables the KEB function. The drive detects a power loss due to
the DC bus voltage or the multi-function digital input KEB command, decelerates immediately and
maintains its own DC bus voltage using the regenerative energy from the motor (load) to continue
control of the motor during deceleration.
If the KEB command is not programmed to a multi-function digital input and Selection of Operation
after Momentary Power Loss (parameter n081) is set to 3, KEB monitors the main circuit DC bus
voltage.
・KEB Start Voltage: DC bus voltage ≦n048
・KEB Release Voltage: DC bus voltage ≧n048＋15VDC (30VDC for 460V units)
When the KEB command is set to the multi-function input and the run command is maintained
during the power loss, the drive monitors the status of the KEB command. After the Power Loss
Detection Relay Delay Time (n144) elapses, the drive will recovery from the power loss when the
KEB command turns OFF and DC bus voltage exceeds the KEB releasing voltage by
re-accelerating up to the speed obtained when KEB operation started. The motor decelerates to a
stop without re-acceleration if the run command turns OFF during a momentary power loss or a
long-term power loss occurs. (Unless the KEB command is set to the multi-function input, the drive
specifies the recovery from the power loss according to the status of DC bus bar voltage after the
Power Loss Detection Relay Delay Time (n144) elapses, and re-accelerates)
When the KEB operation starts, the motor decelerates in KEB Deceleration Time 1 (n045), and then
in KEB Deceleration Time 2 (n046) after KEB Deceleration Ratio Changeover Time (n047) elapses.
Therefore, set a fast deceleration ratio only when the KEB operation starts so that the drive DC bus
bar voltage can be maintained immediately.