
B–65142E/04
7. BUILT–IN BRAKEDESCRIPTIONS FOR THE α series
85
When a motor with brake is applied to gravity shafts, the fall amount of
the shaft in a power interruption or an emergency stop, or when the CNC
is turned OFF may be a problem. The following describes an effective
way of minimizing this fall amount.
(1)Provide a control switch or relay on the DC side (see position in figure
below) of the brake circuit to quickly activate the brake.
(2)It is essential that this switch or relay be disconnected as quickly as
possible to shorten the fall amount in the vertical axis.
(3)Taking the power supply for actuating the relay directly from the mains
power supply (mainly 200 VAC in Japan) is effective for quickly
disconnecting the relay in a power interruption.
(4)To prevent the shaft from falling during an emergency stop, it is
sometimes effective to use the “brake control function” in the servo
software. This function enables continuous excitation of the motor
until the motor built–in brake operates.
For details, see Parameter Manual B–65150E.
Braker
Relay
Coil
Spark killer
Surve absorber
Motor
Brake
coil
Switch
Rectifier
To NC Servo amplifier
7.7
REDUCING THE
BRAKE SHAFT FALL
AMOUNT