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Electromagnetic Clutches & Brakes

What makes Thomson's electromagnetic clutches and brakes superior?

Thomson has a long history of manufacturing quality in electromagnetic clutches and brakes. Today our electromagnetic clutches and brakes are working in applications specific to factory automation, material handling, automotive, aviation, defense, aerospace, medical, office machine, robotics and servo-motor manufacturing industries. These products are the foundation of the broad range of standard and custom electromagnetic clutch and brake products currently available to our customers.

Thomson offers two design types of electromagnetic clutches and brakes technologies:

Wrap Spring Products

Genuine Wrap Spring electromagnetic brakes consist of three basic elements: input hub, output hub and spring. The spring inside diameter is slightly smaller than the outside diameter of the input and output hubs. When the spring is forced over the two hubs, rotation in one direction wraps it down tightly on the hubs, positively engaging them together. The greater the force of rotation, the tighter the electromagnetic brake spring grips the hubs. Thomson offers the following combinations of electromagnetic brake wrap spring designs:

Standard CB Series Clutch-Brake Package

CB Series combination clutches and brakes accurately start and stop loads driven by a continuously rotating power source. CB units operate from a single AC or DC pulse, stopping the load within ±½° noncumulative at speeds up to 1800 RPM. Each unit is pre-engineered and pre-assembled for easy installation.

Standard CB series clutch brake design

Super CB Series Clutch & Brake Package

Super CB Series combination of clutches and brakes accurately start and stop loads driven by a continuously rotating power source. CB units operate from a single AC or DC pulse, stopping the load within ±½° noncumulative at speeds up to 750 RPM - depending on size. Each unit is pre-engineered and pre-assembled for easy installation. Super CB clutches and brakes provide 3 to 5 times longer life!

Super CB series electromagnetic clutch brake design package

SAC Clutch Series

The SAC Series features four models of pre-assembled, solenoid actuated, wrap spring clutch packages. SAC units operate from a single AC or DC pulse to accurately start loads at speeds up to 1800 RPM, depending on size. Adjustable stop control collars provide easy and accurate output stop position settings. A typical SAC Series clutch will bring the load up to speed within 3 milliseconds. They are easy to interface with PCs and industrial control systems. SAC Series clutches are accurate, repeatable, fast acting, simple, maintenance free, and low cost.

SAC Series Electromagnetic clutch design

PSI Clutch Series

PSI Series clutches represent the most fundamental wrap spring clutch design. As a start-stop or single revolution clutch, it is actuated simply by external blocking or releasing of the stop collar. As a simple overrunning clutch it provides positive engagement of load to power source, but permits free overrunning when input power is slowed, stopped or reversed. All units can be supplied with hub input/shaft output or vice versa. Designed for applications where direct mechanical control is desired, the PSI Series clutch is a reliable, easily applied, low cost solution.

PSI Series electromagnetic clutch design

SA Clutch Series

SA Series clutches come in size 250 and 500, in both clockwise and counter-clockwise configurations. SA units are available as hub or shaft input, and can operate with an AC or DC power source. Each unit is preengineered and pre-assembled for easy installation.

SA series electromagnetic clutch design

Custom Engineered Products

Engineered products are specially designed to solve specific and unique application requirements. The products shown are the result of years of experience in providing innovative solutions for applications including paper feed drives, agriculture equipment, copiers, robotics, etc. These solutions are now available as engineered products which include the DL, MAC, SP, and BDNB Series.

Custom engineered electromagnetic brake designs

Friction Electromagnetic Brakes

Friction Electromagnetic clutches and brakes connect a rotating or stationary input to an output load. In general, the exultation of an electromagnetic field coil causes interaction between a rotating or stationary field assembly (input) with a load (output) via a pulley, gear, or stationary mount. Electromagnetic clutches provide an efficient, electrically switchable link between a motor and a load. Electromagnetic brakes use similar designs to provide an efficient, switchable means of stopping and/or holding the load. Under this fundamental design, Thomson offers a variety of electromagnetic clutch solutions to meet almost any application:

SB Series Spring-Set Brakes (Power-off)

Our SB Series is designed as a servo brake with low backlash splines for high performance applications. The spline drive construction withstands high impact stresses imparted by typical servo systems. High temperature operation is available with Class H case assemblies containing long live brake linings (non-asbestos) and TFE coated leads. With low inertia rotating components, high rates of acceleration are obtainable.

SB Series electromagnetic brakes

FSB Series Electromagnetic Brakes (Power-off)

FSB Series brakes are designed in small frame size packages. The brake coupling armature assembly is secured to a shaft by set screws. Spring-set electromagnetic power-off brakes provide a safe, efficient means of stopping and/or holding a load in the absence of power. While the field (electromagnet) assembly is fixed and prevented from rotating, the rotor assembly is secured to the shaft. In the absence of power, the fixed and rotating components are engaged, thus stopping and/or holding the load. When the coil is energized, rotating components are disengaged thus allowing the shaft to freely rotate.

FSB series electromagnetic brakes

AKB Series High Performance Spring-Set Brakes

The AKB Series are specifically designed for use on the back end of servo or stepper motors. These spring-set electromagnetic power-off brakes provide a safe, efficient means of stopping and/or holding a load in the absence of power. While the field (electromagnet) assembly is fixed and prevented from rotating, the rotor assembly is secured to the shaft. In the absence of power, the fixed and rotating components are engaged, thus stopping and/or holding the load. When the coil is energized, rotating components are disengaged thus allowing the shaft to freely rotate.

PMB series electromagnetic brakes

The PMB Series is a power-off, DC spring set brake that provides a low-cost, multi-functional brake alternative for many applications. A simple, splined hub attaches to the shaft with a set screw and keyway and includes an anti-rattle feature for quiet operation. The series offers a superior torque to size ratio and heat dissipation. An adjustment collar allows the torque to be varied to the application. These brakes easily mount to the motor or the frame - mounting hardware included. Fully potted coils meet minimum requirements for class “F” insulation.

PMB series electromagnetic brakes

MBRP Metric Series Spring-Set Brakes (Power-off)

The MBRP Series are a power-off, DC spring set metric brake that provides a low-cost, multi-functional brake alternative for many applications. A simple, square drive hub attaches to the shaft with a set screw and keyway and includes an anti-rattle feature for quiet operation. The series offers a superior torque to size ratio and is engineered with friction material on the rotor assembly to boost maximum brake performance and extend life. Fully potted coils meet minimum requirements for class “F” insulation.

MBRP series electromagnetic brake design

BF Series Electromagnetic Brakes (Power-on)

BF Series electromagnetic power-on brakes provide an efficient, switchable means of stopping and/or holding the load. While the field (electromagnet) assembly is fixed and prevented from rotating by a flange, the armature assembly is secured to the shaft. When the coil is energized, the armature engages the friction surface of the fixed field (electromagnet) assembly, thus stopping and/or holding the load.

BF Series electromagnetic brake design
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