10
1 INTRODUCTION
1.5 Electromagnetic brake
1.5
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 which is interlocked with an external emergency stop switch.
• 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. Ensure enough time between releasing the electromagnetic brake and starting
the rotary servo motor. Be sure to check the operation delay time with an actual machine.
• For details of the circuit configuration and timing chart, refer to the following.
MR-JET User's Manual (Hardware)
• 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.
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 appropriate for the rotary servo motor series being used.
When a diode is used as a surge absorber, the electromagnetic braking time becomes longer.
Sound generation
The brake lining may rattle during a low-speed operation; however, it poses no functional problem.
The noise may be reduced or eliminated by the machine resonance suppression filter set with the servo amplifier parameters.
For details, refer to "Machine resonance suppression filter" in the following manual.
MR-JET User's Manual (Adjustment)
U
RA
B
Contacts must be opened when ALM (Malfunction)
or MBR (Electromagnetic brake interlock) turns off.
Contacts must be opened with the emergency stop switch.
Rotary servo motor
Electromagnetic
brake
24 V DC
VAR
B1
U
B
B2
VAR
B1
U
B
B2
Electromagnetic brake
Electromagnetic brake
Switch
Switch
24 V DC power
supply for
electromagnetic
brake
24 V DC power
supply for
electromagnetic
brake
or
