Types of Clutches and Brakes

Clutches and brakes are used to control the rotational speed of moving parts. A clutch engages in-line or parallel shafts to start or alter the speed of a load. A brake is a device that transfers energy to the machine frame or motor flange to slow, halt, or hold a load statically. For clutches and brakes, various technologies are employed, including (in descending order of force) pneumatic, electromagnetic, mechanical, and hydraulic. Torque, diameter, response time, power budget, and cost are important considerations.

Electromagnetic Clutches and Brakes

Electromagnetic clutches allow for the efficient and electrically switchable operation of a motor and a load. These clutches can be utilized with parallel or in-line shafts connected by pulleys, gears, or sheaves. Current going via a field coil in an electromagnetic clutch provides a magnetic flux distribution that magnetizes a rotor. The magnetic force attracts an armature plate coupled to the load on the rotor. The load turns with the rotor and driving shaft due to their contact. Teeth or friction plates can be used to augment magnetic contact. When the field coil’s current is released, the armature and rotor disengage. 


Electromagnetic brakes work in a similar way. They transmit force from the load to the machine frame, backstop, or motor flange, rather than from the drive shaft to the load. Electromagnetic brakes can be powered on or powered off. Power-on designs are similar to electromagnetic clutches, but they only have one revolving component—the armature assembly. Power-off brakes are classified as either spring-set or armature. The field-coil assembly is fixed in both circumstances, but the rotor (spring-set type) or armature (permanent-magnet type) assemblies are free to revolve until the brake is applied. 

In the absence of electricity, spring-set power-off brakes provide a safe and efficient way of stopping and/or retaining a load. Compression springs inside a field assembly provide the real braking force. They are suitable for either static or low-speed engagement situations. They can wear quickly at high speeds or duty cycles.

Clutches and brakes that are pneumatic or hydraulic

Pneumatic and hydraulic clutches and brakes, often known as industrial clutch and brake systems, are standard industrial solutions. Hydraulic designs may generate large amounts of force. However, they may be nasty to deal with and require constant upkeep. Pneumatic devices are cleaner than hydraulic devices, but their force capacity is restricted. They are better suited to lighter-duty applications. If the application is not important and pressurized air is being utilized elsewhere on the machine, a pneumatic clutch or brake may be an appropriate alternative. Otherwise, an electromagnetic brake or clutch is generally a better solution for such light weights.

Overload Clutches

Overload clutches guard against torque overload caused by jams or collisions. A spring-loaded cam follower positioned in a single-hub cam detent in a Torq/Gard overload clutch forces the hub and clutch to revolve simultaneously. If the torque reaches a certain limit, the gadget trips and disengages. When the unit is restored to the set position after tripping, it automatically resets, generally by running the machine when the jam or overload is cleared. Shaft bushings are utilized to adapt a standard maximum bore unit to the application shaft. Torq-Gard hubs are designed to be rotated in both directions.


There are several industrial clutch and brake designs and sizes for various load types, torque requirements, and purposes. The goal of creating customized clutches and brakes for various industrial machinery is to provide each operation with the needs needed to complete the task correctly and keep it operational.