1. Normally Open Brake: Power-Driven Safety Guard
Working Principle:
The normally open brake remains "on" (i.e., not braking) in an unpowered state, and only generates braking force when electricity, hydraulic pressure or air pressure is applied. This design is similar to the light switch we use in daily life - it needs to be actively operated to work.
Core features:
In the default state, the brake pads are separated from the brake disc and no friction is generated
Continuous energy input is required to maintain the braking state
Automatically release the brake when the power is off or the power is lost
Fast control response speed, and the braking torque can be precisely adjusted
Typical application scenarios:
1. Production line equipment that requires frequent start and stop
2. CNC machine tools with a high degree of automation
3. Servo motor supporting system
4. Occasions requiring precise position control
Advantage analysis:
Significant energy saving effect (only consumes energy during braking)
Good heat dissipation performance, suitable for high-frequency use
Strong dependence on the control system, suitable for modern smart factories
2. Normally closed brake: Failure protection safety expert
Working principle:
Normal closed brakes are just the opposite. In the unpowered state, they rely on spring force, gravity or permanent magnets to maintain the braking state, and external energy must be applied to release the brake. This is similar to the handbrake of a car-it is in the braking state by default and needs to be actively released.
Core features:
In the default state, the brake pad contacts the brake disc to generate braking force
Automatically enter the braking state (failure protection) when power is off or faulty
Mechanical springs are usually used as the braking force source
High safety, especially suitable for vertical load occasions
Typical application scenarios:
1. Lifting equipment and elevator systems
2. Mining machinery and engineering equipment
3. Wind power pitch control system
4. Any occasion that requires power-off safety protection
Advantage analysis:
High intrinsic safety, in line with the principle of fail-safety
Not affected by sudden power outages, ensuring the safety of personnel and equipment
Relatively simple maintenance, high reliability
3. Technical comparison and selection guide
| Comparison items | Normally open brake | Normally closed brake |
|---|---|---|
| Default state | No braking | Braking |
| Energy consumption characteristics | Energy consumption during braking | Energy consumption during release |
| Safety | Dependence on control system | Intrinsic safety |
| Applicable frequency | High frequency | Medium and low frequency |
| Maintenance cost | Relatively high | Relatively low |
| Typical application | Automated production line | Lifting equipment |
Selection suggestion:
1. Prioritize safety: Select normally closed type for vertical movement and heavy loads
2. Consider energy consumption factors: It is more economical to select normally open type for high frequency use
3. System integration requirements: Normally open type is easier to control for systems with high automation
4. Failure mode analysis: Evaluate the risks that may be caused by power failures
4. Maintenance and use precautions
No matter which brake is selected, correct maintenance is crucial:
1. Regular inspection: Brake pad wear, spring tension, air/hydraulic system sealing
2. Cleaning and maintenance: Prevent oil and dust from affecting the braking effect
3. Performance test: Regularly verify the braking torque and response time
4. Environmental adaptation: Special environments such as high temperature and humidity require the corresponding protection level
5. Professional installation: Ensure the centering accuracy of the brake and the shaft
Conclusion
Normally open and normally closed brakes have their own advantages and disadvantages. There is no absolute distinction between good and bad. The key is to make the right choice based on the specific application scenario. Understanding how they work can not only help engineers make better design decisions, but also enable equipment operators to use equipment more safely and efficiently.
What type of brakes do you use in your factory? What related problems have you encountered? Welcome to share your experience in the comments section!
