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1. INTRODUCTION
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1.3 Electromagnetic brake
CAUTION
The electromagnetic brake is provided to prevent a drop at a power failure or
servo alarm occurrence during vertical drive or to hold a shaft at a stop. Do not
use it for normal braking (including braking at servo-lock).
The electromagnetic brake has a time lag. Use the electromagnetic brake so that
servo motor control starts after the electromagnetic brake has completely opened.
Be sure to check the operation delay time with a real machine.
Configure an electromagnetic brake circuit so that it is activated also by an
external EMG stop switch.
For details of the circuit configuration and timing chart, refer to each servo
amplifier instruction manual.
While the electromagnetic brake is opened, the motor may be raised to high
temperature regardless of driving.
The life will be shorten under sudden acceleration/deceleration conditions.
The servo motor with an electromagnetic brake can be used to prevent a drop in vertical lift applications or to
ensure double safety at an emergency stop, for example. When operating the servo motor, supply power to
the electromagnetic brake to release the brake. Switching power off enables the brake.
(1) Electromagnetic brake power supply
Prepare the following power supply for use with the electromagnetic brake only. The electromagnetic
brake terminals (B1 and B2) have no polarity.
Electromagnetic brake
Switch
VAR
B1
U
B
24 V DC
power supply for
electromagnetic brake
B2
Electromagnetic brake
Switch
VAR
B1
U
B
24 V DC
power supply for
electromagnetic brake
B2
or
The surge absorber (VAR) must be installed between B1 and B2. For the selection and example of
surge absorbers, refer to "Electromagnetic brake characteristic" in the chapter of each servo motor
series.
When you use a diode for a surge absorber, the electromagnetic braking time will be longer.
(2) Sound generation
Though the brake lining may rattle during operation, it poses no functional problem.
If braking sounds, it may be improved by setting the machine resonance suppression filter in the servo
amplifier parameters. For details, refer to each servo amplifier instruction manual.