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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
3. Brake circuit
Connect the contact of the relay that is turned off at power failure to DC24V side of the
brake circuit shown as the following figure, so as to brake soon after detecting the power
failure. Connect the coil of the relay to the input power to cut the brake circuit at power
failure.
Brake circuit
Input power for
power failure detection
(For operating the relay)
DC24V
Relay for power
failure detection
Motor
Brake
coil
Spark killer
Input power
for the brake
Relay for operating the brake.
Turn on this relay after S
signal becomes ”1”.
Note) The contact of the relay must be connected to DC24V side of the brake circuit.
If the contact of the relay is connected to AC side of the brake
circuit, the timing that the brake
becomes effective is delayed.
The time from power failure till the brake becomes effective.
”Operate time of brake” after power failure is the total of ”Reset time of relay”
and ”Response time of brake”.
Operate time of brake
Response time of brake
Make
Reset time of relay
Brake is effective
Power failure
Input power voltage
Status of brake
BreakContact of relay
Reset time of relay: The time from cutting off the rated voltage supplied to the coil of the relay
till the contact of the relay is turned off (“a contact” is opened).
Response time of brake: The time from cutting off the rated voltage supplied to the coil of the
brake till the brake becomes effective.
Operate time of brake: The time from occurring the power failure till the brake becomes
effective.