Electromagnetic Clutch / Brake: Working Principle, Advantages ,Disadvantages and Application.

The electromagnetic clutch is a highly efficient device that serves as a crucial component in various mechanical equipment. By using the principles of electromagnetism, Electromagnetic Clutch  enables seamless transmission of mechanical power between two rotating shafts. Being selected in a wide range of applications, from automotive systems to industrial machinery, electromagnetic clutches offers precise control over the engagement and disengagement of power, offering improved efficiency, smooth operation, and enhanced functionality in modern mechanical machine.

Through this base Electromagnetic Clutch article in our blog, you will know about Electromagnetic clutch, its definition, working principle, advantages and some noteworthy disadvantages.  

Part 1: What is an Electromagnetic Clutch? 

The electromagnetic clutch is a device being used in various mechanical systems to engage and disengage power transmission between two rotating shafts fixed on the machine. It operates through electromagnetic force to facilitate the engagement and disengagement of the clutch mechanism in various applications. What is more, this type of clutch is a subset of automobile clutches, functioning based on friction principles. It features precise control over power transmission and finds use in a wide array of industries, including automotive, industrial, and manufacturing sectors.

Fig 1: Electromagnetic clutch

Part 2: Knowing the Electromagnetic Clutch Construction

An electromagnetic clutch is composed by a clutch of two main parts: the rotor and armature. The rotor is joined to the driving shaft, while the armature is connected to the driven shaft. When an electrical current is on, the electromagnetic field attracts the armature, engaging the clutch and transmitting power between the two shafts.

Fig 2: Electromagnetic clutch Construction

2.1 Flywheel

The flywheel is fixed in the engine's crankshaft and facilitates the transmission of power or torque from the engine to the clutch shaft. When the pressure plate engages with the flywheel, this transfer of power occurs.

2.2 Winding

Installed on the flywheel, the winding carries an electric current from the battery, generating a magnetic field around it. When current flows through the winding, the pressure plate establishes contact with the flywheel, leading to clutch engagement.

2.3 Friction Plate

Mounted on the clutch shaft, the friction plate boasts friction lining on both sides. When the winding receives current, the pressure plate presses the friction plate against the flywheel, ensuring proper contact and enabling power transmission.

2.4 Pressure Plate

Positioned on the clutch shaft, the pressure plate plays a pivotal role in the clutch's operation. It is responsible for pressing the friction plate against the flywheel when current flows through the winding. This engagement facilitates the transmission of power/torque.

2.5  Battery

The battery supplies the necessary current to the winding. A clutch switch is used to control the current supply to the winding. In the engaged position of the clutch, the clutch switch is off, allowing current to flow through the winding. Conversely, the clutch switch is turned on in the disengaged position, preventing current from flowing through the winding.

Part 3: Working Principle of Electromagnetic Clutch

When an electric current flows through the magnet component and generate a magnetic field. The rotor part of the electromagnetic clutch becomes magnetised, and sets up a loop which attract the armature. The movement of the armature against the rotor creates a frictional force. Within a very short period of time, this load is accelerated to match the speed of the rotor, which increases the output of the clutch.

Electromagnet clutches and gearboxes are used in a wide range of systems, including automobiles, locomotives and a wide range of machines, such as lawnmowers and factory machinery.

The working of a typical Electromagnetic Clutch is enumerated as follows:

• An electromagnetic clutch functions as a mechanism for either connecting or disconnecting two shafts known as the driving shaft or engine shaft and the driven shaft or gearbox shaft. 
• Initially, the clutch remains disengaged, resulting in an air gap between the rotor and the hub.
• The engine's activation prompts the rotation of the rotor, which is linked to the engine shaft.
• A DC battery supplies a Direct current to the clutch winding.
• Applying high-voltage DC current transforms the winding into an electromagnet, generating an attractive force on the armature.
• This armature, in turn, exerts pressure on the friction plate, causing it to move towards the rotor and initiating the rotation of the hub.
• Consequently, the hub undergoes rotation, allowing the rotor to transmit the complete 100% torquewhen in the engaged state.
• Upon pressing the clutch switch or pedal, the battery discontinues the supply to the winding, eliminating the electromagnetic force and causing the clutch to revert to the disengaged position.
• This design combines both electromagnetic and mechanical principles, effectively merging magnetic effects with traditional clutch mechanisms.

Part 4: Advantages of Electromagnetic Clutch

The advantages of this clutch include:

• Electromagnetic clutches offer rapid engagement and disengagement, providing quick response times.
• They provide smooth and gradual engagement, minimising shock and wear on connected components.
• Electromagnetic clutches allow for precise control over power transmission, enhancing overall system performance.
• They can be engaged or disengaged remotely, eliminating the need for direct physical contact.
• These clutches can transmit high torque values efficiently, making them suitable for heavy-duty applications.
• Their design leads to fewer moving parts, resulting in reduced maintenance requirements.
• Electromagnetic clutches consume power only when engaged, contributing to energy efficiency.
• Torque transmission can be adjusted by controlling the current supplied to the clutch winding.

Part 5:  Disadvantages of Electromagnetic Clutch

The disadvantages of this clutch are:

• Electromagnetic clutcheswill generate heat during operation, potentially leading to thermal issues.
• The design is complex than traditional clutches, increasing manufacturing complexity and costs.
• Dependon electrical power source makes them vulnerable to power supply interruptions or failures.
• Friction between plates may lead to wear over time, necessitating periodic maintenance.
• Factors such as dust, moisture, and contaminants can impact their performance and lifespan.
• Efficiency might decrease at high rotational speeds due to the effects of eddy currentsand other electromagnetic phenomena.
• The operation of electromagnetic clutches might cause electromagnetic interference with other nearby electronic devices.

Part 6 : The Applications of Electromagnetic Clutch

Electric tooth clutches, electromagnetic tooth clutches and electric multiple disc clutches are used where high torque and small size are required. Customer applications include machine tool manufacturers, CNC machines, lathes, milling machines and others. They are used by manufacturers of AC and DC electric motors including brake motors, brushless DC motors and servo motors.
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Applications for these high reliability brakes include overhead doors, cranes, marine, construction equipment and brakes for super quiet use in stage and theatre can be supplied. Manual release levers or emergency release mechanisms can be available on many of these products if needed.

• Used in automatic transmissions to control gear shifts and provide smooth power transmission.
• Employed in machinery like printing presses, conveyor systems, and packaging equipment for controlled power transfer.
• Found in tractors and agricultural machinery for engaging and disengaging power to various components.
• Used in lathes, mills, and other machining equipment to control spindle rotation and tool engagement.
• Applied in robotics for controlling motion and power transmission in joints and limbs.
• Utilised in forklifts, cranes, and material handling equipment for controlled movement and lifting.
• Found in weaving and spinning machines to control fabric tension and movement.
• Used in marine vessels for controlling propeller engagement and disengagement.
• Applied in automatic doors and gates for smooth and controlled opening and closing.
• Used in printing machines for precise control of paper feed and print rollers.
• Found in medical devices like imaging systems for controlled movement and positioning.