This style of brake is also known as a ‘power-off engaged’ brake. A spring actuated electromagnetic brake provides reliable braking when the power is disengaged, and excellent performance in long-term holding applications. In a spring actuated, or spring applied brake, compression springs push the armature plate into the rotor disc to halt and hold movement when power is disengaged. This feature provides fail-safe braking, and allows the brake to maintain position over long periods of time, thus preventing machinery from “coasting” when powered off.
Miki Pulley Spring Actuated Brakes
Miki Pulley manufactures a full line of electromagnetic spring actuated brakes, with different models and sizes available for braking, holding, or both braking and holding. Advantages of our brake lineup include:
This spring actuated, power-off engaged brake features a power controller that allows a split-second of 24VDC power to overcome spring inertia, then steps down to a power-saving 7VDC. This is ideal when exploring overall energy cost savings while mitigating heat buildup in the stator. The BXR-LE (Low-Energy) spring actuated brake also features a compact, low-profile design, with a 3-hole bolt circle for mounting. Clamp style or Press-Fit rotor hub options are available.
Brake torque: 0.044 ft-lb to 2.36 ft-lb (0.06Nm to 3.20Nm)
Brake outer diameter: 1023” to 2.08” (26.0mm to 71.0mm)
Ambient temperature: 14°F to 104°F (-10°C to 40°C)
BXR Model Spring Actuated Brakes
The BXR spring actuated brake is a holding brake that can serve as a dynamic brake in emergency situations. The unique, low profile design is 2/3 the thickness of our other BX brakes. Saving space is key, as is reducing overall length in a brake/servomotor combination. Weight is also dramatically reduced. This is important with mass reduction and cantilevered loads, such as those typically seen in robotic arm applications. To top off all these features, the energy saving design reduces the temperature buildup of the coil.
Brake torque: 3.688 ft-lb to 40.566 ft-lb (5Nm to 55Nm)
Brake outer diameter: 3.287” to 7.280” (83.5mm to 185mm)
Ambient temperature: 14°F to 104°F (-10°C to 40°C)
BXW Model Spring Actuated Brakes
The BXW spring actuated brake power-off engaged is used for either braking or holding, but also a separate combination of braking & holding. Three sub-models are available: L-Type (for braking), S-Type (for holding only), and H-Type (for braking and holding).
These brakes function at a full torque rating right out of the box; no “running in” is required to season the abrasive element. To reduce noise, a strategically placed flat spring reduces the clatter produced by small vibrations between the hub and disc during high speed rotation.
Brake torque: 0.88 ft-lb to 0.369 ft-lb (0.12Nm to 5.2Nm)
Brake outer diameter: 1.457” to 2.953” (37mm to 75mm)
Ambient temperature: 14°F to 104°F (-10°C to 40°C)
BXW-R Model Spring Actuated Brakes
The BXW-R model is constructed with servo motors in mind. This spring-actuated, power-off engaged brake offers reliable braking when the voltage is disengaged, and superb performance for long-term holding applications. When power is disconnected, internal compression springs push the armature plate into the friction disc stopping and holding movement. The BXW-R is mainly intended for use as a holding brake.
The main difference between the BXW-R and the baseline BXW option is that the ‘R’ models are specifically designed to be mounted to servo motors. This brake will function at full torque rating right out of the box—no “running in” is required to season the abrasive element
Brake torque: 0.22 ft-lb to 1.84 ft-lb (0.3Nm to 2.5Nm)
Brake outer diameter: 1.299” to 2.520” (33mm to 64mm)
Ambient temperature: 14°F to 104°F (-10°C to 40°C)
BXL Model Spring Actuated Brakes
The compact BXL spring actuated power-off engaged brake is designed exclusively for dynamic braking. The composite disc is designed with wear resistance in mind, resulting in a long service life. Torque fluctuation is minimal even when halted from maximum RPM. Excessive noise during braking is reduced by use of a flat spring strategically placed on the rotor hub.
Brake torque: 1.475 ft-lb to 16.226 ft-lb (2Nm to 22Nm)
Brake outer diameter: 3.268” to 76.221” (83mm to 158mm)
Ambient temperature: 14°F to 104°F (-10°C to 40°C)
BXH Model Spring Actuated Brakes
The BXH spring actuated brake is designed primarily for emergency braking and holding. Dimensionally, it is the same as the BXL. However, it provides double the operating torque for dynamic braking purposes. This SL brake will function at full torque rating right out of the box—no “running in” is required to season the abrasive element.
Brake torque: 2.950 ft/lb to 32.452 ft/lb (4Nm to 44Nm)
Brake outer diameter: 3.268” to 76.221” (83mm to 158mm)
Ambient temperature: 14°F to 104°F (-10°C to 40°C)
