What Is The Function Of The Slip Rings In An Electric Generator? What a Slip Ring Is and How It Works


Slip rings are used to create a one-way path for current or power to flow in a generator. They ensure there is no change of direction of power within the generator so that the device can supply power continuously. A slip ring acts as the contact allowing the transmission to occur as they complete the generator’s electric circuit. This way, the generator is powered electrically to work efficiently.

What Is A Slip Ring?

A slip ring is an electromechanical tool that aids power and electrical signals transmission from a stationary structure to a rotating one while maintaining contact all through. They are two hollow rings connected to one end of the armature coil; hence rotate on the armature coil’s rotation to allow contact with the brushes. They are insulated outside to avoid power or signal transmission elsewhere apart from the armature, whose contact is facilitated by the brushes sliding over the rings.

How Does A Slip Ring Work?

Slip rings have two major parts consisting of rotating rings and stationary brushes. The rings and brushes slide against each other creating electrical contacts. On coming into contact, the power and current signals are transmitted. At no particular point do they break contact as long as the rotor is in motion hence the continuous flow of current. The slip rings to complete the electric circuit in the generator hence continuous and efficient transmission of power. 

Where Do You Use A Slip Ring?

Slip rings are used in most industrial automation applications and equipment powered electrically or require current flow to work. They include equipment like cranes, both the jib and tower ones, and hose and cable winders. These equipment require alternate current to function hence the use of regular slip rings. The equipment relies on direct current use commutators or the modified slip rings called slip ring commutators to transmit power enabling the motors to work.

What Is A Slip Ring Commutator?

A slip ring commutator is a modified slip ring for direct current motors. It is special since it has the added purpose of reversing electrical current and actualizing contact between the brushes and rings to transmit power. Direct current motors rely on the direction change to work efficiently as that’s how its electric circuit is made complete. 

What Is The Difference Between A Slip Ring And A Commutator?

A slip ring is used in alternating current motors to provide a continuous one-way transmission of power and signals. In contrast, a commutator is used in direct current motors to reverse the current’s polarity in the armature windings. Both devices’ main aim is to complete electric circuits and maintain power transmission flow for both alternating current motors and direct current motors. Each of them is perfectly modified to suit its functions. 

How Many Slip Rings Are There In An Electric Generator?

An alternating current motor requires a complete circuit to function since it relies on the feed and return system. This means that a minimum of two slip rings is required, and they should be as many as the rotor windings in the generator. A basic electric generator has three slip rings, with each connected to the three-rotor windings. This ensures efficient transmission of power and signals. Depending on the motor’s size and purpose, the slip rings could be more as long as the required amounts of power are transmitted and put to use in the motors.

What Are Slip Rings Made Of?

Slip rings are majorly made of copper and an alloy of copper or phosphor bronze. These particular metals are used due to their high conductivity rate, high resistance to oxidation rate and low wearing out rate. The brushes are made of silver graphite. Silver is for low contact and graphite for lubrication so that they can last longer. The rings’ material must be harder than that of the brushes to ensure they last long despite the contact, even at very high speeds. Above all conductivity of current in the material on rings and brushes must be high and efficient for transmission.

What Is The Use Of Split Rings?


Split rings are used in direct current motors as they let current change direction every half rotation. They shift magnetic poles every half rotation, causing the motor’s shaft to continue experiencing torque and rotation in the same direction on every shift. The current therefore keeps changing direction, and this keeps the motor running efficiently. Split rings are split in shape, unlike semicircular slip rings. Its shape allows for the shifts as the contacts to slide over the brushes change every half rotation allowing for a direction change in the current flow.

What Is The Difference Between A Slip Ring And A Split Ring?

The slip ring is used in the alternating current motors, while split rings are used in direct current motors. The slip ring allows for continuous flow of current in one direction while a split ring changes the direction of flow of power ever half rotation. Besides, the slip ring is shaped as a complete circle, while a split ring has two semicircular contacts that allow for a direction change in the flow of current. Both serve the purpose of completing the electric circuits but differently. 

What Is The Difference Between A Slip Ring Motor And An Induction Motor?

A slip ring motor has a wound rotor as it is coiled to provide more surfaces for contact with the brushes, while that of an induction motor has a squirrel cage shaped rotor. For the slip ring motor, its starting torque is high, while the induction motor is low. The force produced by the power determines the torque, and clearly, the slip ring motor has more power.  Thus, the power generates high force leading to a high starting torque in the motor. However, changes may occur depending on the power supply and other relevant factors.

What Is Slip Speed?

Slip speed is the speed at which an induction motor works. It shows the rotor’s relative speed to the speed of the magnetic field it is operating on. The slip speed is achieved by finding the difference between the motor’s synchronous speed and rotor speed.

Do Alternators Have Slip Rings?

Yes, slip rings are found in the alternators with the sole purpose of providing direct current excitation to the rotor of the alternator. This way, the alternator can maintain a continuous flow of current even as direction change occurs within the motor.

How Long Does A Split Ring Last?

On average, a split ring lasts up to 10 years. The number of operating hours and motor speed are the main factors determining how long they last. Due to the constant contact between the brushes and rings, each has to be in good shape to avoid damaging others. Proper care and maintenance of slip rings improve their durability compared to those exposed to factors contributing to wearing out.

How Do You Maintain Slip Rings?

Slip rings are not so delicate but require good care and maintenance. Regular inspection of their physical state and efficiency in performing their duty is a major role in maintenance. This way, any mistakes detected early and fixed or changed before more damage is caused to the slip rings or the brushes. You should also do regular cleaning to remove dust, oil and water. Since the brushes are made of weaker material than the slip rings, they should be replaced regularly. This is because brushes wear out faster and could damage the slip rings when they come into contact. 

How Do I Choose A Slip Ring?

To pick out the most efficient slip ring for your motor, you need to have a vast knowledge of the motor’s features and model. Know the total number of circuits within the motor and how many open ends each have since each open end will need a slip ring. Know the voltage that flows within the motor to have it working efficiently and at the required speed. Besides, you should know how many amperes of an electricity flow within each electric circuit. Another thing to look at is the motor’s operating speed to pick slip rings that can keep up with that. Also, be able to identify the mounting type the motor has to pick the appropriate slip rings. 

Final Word

Slip rings are quite essential in industrial motors. Proper knowledge of the same is required to ensure only the best decisions and choices are made concerning slip rings and their accessories. Differentiating what to use on direct current motors and alternating current motors is also very important to ensure efficiency and safety. Note that electric current can be dangerous if mishandled. Like all other devices, slip rings must be maintained well to ensure they last long and serve their purpose the best way possible.

Leave a Comment