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1.4
Electromagnetic brake
The rotary 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 rotary servo motor, supply power to the
electromagnetic brake to release the brake. Switching power off enables the electromagnetic brake.
Precautions
• The electromagnetic brake on the rotary servo motor is designed to hold the motor shaft and should not be used for
ordinary braking.
• Incorrect wiring, service life, or the mechanical structure (e.g. where a ball screw and the rotary servo motor are coupled via
a timing belt) may cause the electromagnetic brake to be unable to hold the motor shaft. To ensure safety, install a stopper
on the machine side.
• If it is assumed that a power failure or product malfunction may result in a hazardous situation, use a rotary servo motor
with an electromagnetic brake or provide an external brake system for holding purpose to prevent such hazard.
• Configure an electromagnetic brake circuit that interlocks with the external emergency stop switch.
Contacts must be opened when ALM (Malfunction)
or MBR (Electromagnetic brake interlock) turns off.
Rotary servo motor
Electromagnetic
brake
• 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 release delay time. Ensure enough time between releasing the electromagnetic brake
and starting the rotary servo motor. Check the release delay time with an actual machine.
• For details of the circuit configuration, refer to "Servo motor with an electromagnetic brake" in the following manuals.
MR-J5 User's Manual (Hardware)
MR-J5D User's Manual (Hardware)
• For details of the timing chart, refer to "Electromagnetic brake interlock function" in the following manual.
MR-J5 User's Manual (Function)
• When the electromagnetic brake is released, the temperature of the rotary servo motor may increase regardless of driving.
• The service life of the brake may be shortened under sudden acceleration/deceleration conditions.
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.
24 V DC power
supply for
electromagnetic
brake
A surge absorber (VAR) must be installed between B1 and B2. For a selection example of surge absorbers, refer to the
"Characteristics of electromagnetic brake" section in the chapter of the applicable rotary servo motor series.
When a diode is used as a surge absorber, the electromagnetic braking time becomes longer.
1 INTRODUCTION
14
1.4 Electromagnetic brake
Contacts must be opened with the emergency stop switch.
RA
B
U
B1
Switch
VAR
B
U
B2
24 V DC
24 V DC power
supply for
or
electromagnetic
brake
B1
Switch
VAR
B
U
B2
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