.
No.
3/10
Page
FANUC LTD
DESCRIPTION DESIGN DATE
EDIT
Prevention of Gravity Axis Drop
at Power Failure
in αi series servo system
B-65282EN/05-03
Add newly S.Hanyu 04.11.22 01
1. General
This manual describes how to prevent the gravity axis dropping at power failure in αi series
servo system without Power Failure Backup Module.
Relay for power
failure detection
DC link DC link
24V
24V
24V
24V
Brake circuit
α
i
PSM
Gravity axis motor
α
i
SPM
α
i
SVM
Built-in brake
NC
Power supply
equipment
3
φ
AC200V
(3
φ
AC400V)
Control
power
supply
circuit
AC200V
Control
circuit
C200V to DC24V
Control
circuit
Control
circuit
It is necessary to operate the brake of the gravity axis motor before the excitation of the
gravity axis becomes off, so as to prevent the gravity axis dropping at power failure. To
achieve this action, the following actions are required.
(1) Brake soon after detecting the power failure.
(2) Keep the excitation of the gravity axis motor till the brake of the gravity axis works after
power failure.
Effective
Gravity axis is kept mechanically
Gravity axis is kept electrically
Excitation ON Excitation OFF
Operate time of brake
Power failure
Input power voltage
Status of brake
Excitation of gravity
axis motor
2. Start-up procedure
(1) Construct the brake circuit that can brake soon after detecting the power failure. (Section 3)
(2) Keep the excitation of the gravity axis motor till the brake of the gravity axis works after
power failure. (Section 4)
Check of the time to keep the control power supply. (Section 4-1)
Parameter setting. (Section 4-2)
(3) Confirm the effect. (Section 6)
Configuration
Timing chart