What Is a Stepper Motor Brake?
A stepper motor brake (also known as a holding brake or shaft brake) is a device that decelerates, stops, or holds moving parts in a stationary position.
Based on their operating principle, brakes can be classified into two types: power-off (spring-engaged) brakes and power-on brakes.
The key difference between the two is whether the motor shaft is held in position when power is removed. All brakes sold by StepperOnline are power-off brakes, which are further divided into electromagnetic brakes (Figure 1) and permanent magnet brakes (Figure 2). Their internal structures differ.
Figure 1. Electromagnetic Brake
Figure 2. Permanent Magnet Brake
How a Power-Off Brake Works
In a power-off brake, when the motor is powered on, current flows through the brake coil, generating a magnetic field that disengages the armature plate from the brake rotor, allowing the motor shaft to rotate freely. When the motor is suddenly powered off, the coil loses current and no longer generates a magnetic field. The armature plate is released, and under the force of the spring, the armature plate is pushed against the brake rotor, creating friction that stops and holds the connected transmission components in place.
Selecting an Electromagnetic Brake
When choosing an electromagnetic brake, verify the following:
- The motor has a rear shaft extension, and its diameter matches the brake bore size.
- The motor's rear end bell has mounting holes that match the brake's bolt pattern and hole spacing.
If both conditions are met, the brake can be directly mounted to the motor. If not, we offer custom motor configurations to accommodate your requirements.
StepperOnline offers three models of electromagnetic brakes. The compatible motor frame sizes are listed below:
- SWB-01 — suitable for NEMA 17 motors
- SWB-03 — suitable for NEMA 23/24 motors
- SWB-05 — suitable for NEMA 34 motors
Wiring the Brake
Warning: All brakes sold by StepperOnline require a 24 VDC power supply. Using a different voltage may damage the brake coil or result in unreliable braking performance.
For integrated brake control, the following StepperOnline drivers feature a dedicated brake output interface: DM860T, CL42T-V41, CL57T, CL57T-V41, CL86T, and CL86T-V41. The wiring diagram is shown below:
