Power-off brakes – find manufacturers and suppliers

Power-off brakes are safety-relevant braking and holding systems that are used in particular in automation, conveyor and drive technology.

Their key feature is the so-called "fail-safe" principle:The brake is closed when de-energized and reliably stops or brakes a movement. As a result, fail-safe brakes offer a high degree of safety in the event of power failure, emergency stop situations or malfunctions. They are a central component of modern machine and drive concepts.

Below you will find information on the function and types of power-off brakes, their use and areas of application as well as their advantages, limitations and special features:

How power-off brakes work:

The mode of operation of a power-off brake is based on the combination of spring force and electromagnetic release.
In the de-energized state, integrated compression springs press the friction surfaces of the brake together.
This creates a high braking or holding torque that prevents the movement of a shaft or load.

When the brake is energized, a solenoid coil generates a magnetic field that overcomes the spring force. The friction surfaces are released from each other and the shaft can rotate or move freely.

The main functional features are

1. Spring force as holding energy:
   This is independent of external energy supply.
2. Electromagnetic release:
   For targeted release of the brake
3. Frictional engagement:
   For transmitting the braking torque

The fail-safe principle ensures that the brake closes automatically whenever the voltage drops.

Types of power-off brakes:

1. Spring-applied closed-circuit brakes:
   The most common design. Several pressure springs generate the braking torque.
   These brakes are compact, reliable and widely used.
2. Permanent-magnet quiescent current brakes:
   Here the holding force is generated by permanent magnets.
   The brake is demagnetized or released by applying current.
   They are characterized by low energy consumption.
3. Single-disc and multi-disc brakes:
   Single-disc brakes are simple in design and inexpensive.
   Multi-disc brakes enable higher braking torques with the same size and are used for high loads.
4. Shaft and flange brakes:
   Shaft brakes are mounted directly on the motor or gearbox shaft.
   Flange brakes are designed for mounting on motors or gearbox housings.
5. Modular and integrated brakes:
   These brakes are integrated directly into motors, servo drives or gearboxes and save installation space.

Use and application areas of power-off brakes:

1. Mechanical and plant engineering:
Holding axes at standstill, emergency stop functions, protection against uncontrolled movements.

2. Conveyor technology:
Holding loads in lifting and lowering applications, safe stopping in the event of a power failure.

3. Robotics and automation:
Axis protection for servo drives and position holding when drives are switched off.

4. Elevator technology:
Safety systems for cabins and counterweights.

5. Medical and laboratory technology:
Safe positioning of sensitive devices.

6. Stage and event technology:
Holding movable constructions.

Advantages of power-off brakes:

• Maximum safety thanks to the fail-safe principle: The brake closes automatically in the event of a power failure.
• Reliable holding function: The holding force is maintained even during long downtimes.
• Energy efficiency: Energy is only required to release the brake.
• Versatile designs: Adaptable to different drive and mounting situations.
• Compact integration: Ideal for modern, space-saving drive systems.
• Long service life: Robust design and proven technology.

Limits and special features of power-off brakes:

• Power-off brakes are primarily holding brakes. Continuous dynamic braking can lead to increased wear.
• In applications with frequent braking, additional service brakes or special designs are required.

Power-off brakes are indispensable safety components in modern drive and automation systems. They function according to the fail-safe principle, ensuring reliable holding and braking even in the event of a power failure. Thanks to different designs and versions, power-off brakes can be flexibly integrated into a wide range of applications. Their advantages in terms of safety, energy efficiency and reliability make them a preferred solution wherever controlled movement and protection of man and machine have top priority.

Here you will find an overview of the most important points to consider when purchasing power-off brakes:

Power-off brakes are safety-critical components in machines, systems and drive systems. They play a key role in holding loads safely, performing emergency stop functions and protecting people and machines in the event of a fault. The wrong choice can have serious consequences - from increased wear and functional failures to safety risks. Professional purchasing therefore requires a holistic view of technical requirements, safety aspects, environmental conditions and economic aspects.

• The first step is to precisely define the task of the power-off brake. This must be clarified:
• Should the brake be used primarily as a holding brake or also for dynamic braking?
• Which loads must be held safely?
• What safety function does the brake perform in the event of a power failure or emergency stop?
• Power-off brakes are often overestimated or used incorrectly. A clear definition prevents misuse.
• The required braking torque must be calculated realistically. This must be taken into account:
• Weight and inertia of the moving masses.
• Lever arms, gear ratios and efficiencies.
• Additional forces due to acceleration or inclined positions.
• In practice, a sufficient safety factor should be taken into account, especially for vertical axes or personal protection applications.
• Depending on the application, different types of power-off brakes can be considered.
• Spring-applied brakes are universally applicable and robust.
• Permanent-magnet brakes score points for their low energy requirements.
• Multi-disc brakes enable high torques with a compact design.
• Purchasers should check which design makes technical and economic sense.
• Mechanical integration influences function and service life. Important aspects:
• Mounting position on the motor, gearbox or shaft.
• Available installation length and diameter.
• Flange, shaft or integrated design.
• Alignment and tolerances.
• A poorly integrated brake can lead to increased wear or an uneven braking effect.
• Power-off brakes are primarily designed for holding purposes. To be checked:
• Number of braking cycles per hour
• Frequency of releasing and closing
• Duration of braking operations
• Special designs or additional service brakes are required for high switching frequencies or dynamic braking.
• Braking processes generate heat that must be dissipated. The following points should therefore be taken into account:
• Ambient temperature.
• Power loss of the brake.
• Cooling options due to installation location.
• Insufficient heat dissipation can significantly reduce the service life.
• Electrical integration is a key selection criterion. Important points:
• Rated voltage and current consumption.
• AC or DC version.
• Switch-on and holding currents.
• Response times when lifting and closing.
• A suitable control, often with a rectifier or electronic module, is essential for reliable operation.
• Power-off brakes are often part of safety-related functions. The following must be observed:
• Compliance with relevant machine and safety standards.
• Use in safety-related control systems.
• Documentation and certification.
• For personal protection applications, a standard-compliant design is absolutely essential.
• The application environment influences the choice of material and design. Attention should be paid here:
• Dust, dirt or moisture.
• Corrosive or chemically aggressive environments.
• Vibrations and mechanical loads.
• Special coatings or types of protection may be required.
• Even power-off brakes are subject to wear. Purchasing should therefore pay attention to the following:
• Service life of the friction linings.
• Adjustment options.
• Maintenance intervals.
• Replaceability of wearing parts.
• A maintenance-friendly design reduces downtimes and costs.
• In sensitive applications, noise development and shifting comfort can be relevant.
• Purchasing should not only evaluate the product, but also the quality, manufacturer expertise and service.
• A reliable partner is particularly important for safety-critical components.
• The purchase price is only part of the equation. High-quality brakes are often the more economical choice in the long term.

The professional purchase of power-off brakes requires a careful and holistic evaluation of technical, safety-related and economic criteria. The decisive factor is not only the nominal braking torque, but also the interaction between the safety function, installation situation, operating mode and ambient conditions. Those who systematically take these aspects into account and rely on high-quality, standard-compliant solutions will receive reliable and durable braking systems that guarantee the safe operation of machines and systems in the long term. A sound selection reduces risks, minimizes downtimes and protects people and technology in the long term.

Power-off brakes brakes can be purchased from various suppliers. You will find comprehensive information on manufacturers and suppliers of Power-off brakes around the world on Exportpages.