DC Shunt Motor

In the world of electric motors, the DC shunt engine remains a demonstration of dependability, flexibility, and perseverance. Whether you are in a modern setting, driving a conveyor belt, controlling the speed of a rolling mill, or changing the volume on an old stereo system, odds are good that you’ve experienced a DC shunt motor at work. In electrical motors, series circuits, and equal circuits are ordinarily known as series and shunt. Hence, in DC motors, the associations of the field windings, as well as the armature, should be possibly equal, which is known as DC shunt motors. The principal contrast between DC series motors as well as DC shunt motors primarily incorporates the construction, operation, and speed characteristics. This motor gives highlights like simple turning around control and speed guidelines, and it is low to begin force. Hence, this motor can be utilized for belt-driven applications inside autos as well as modern applications.

What is a DC Shunt Motor?

At its core, a DC shunt motor is a direct-current electric motor intended to convert electrical energy into mechanical movement or we can say that it is a self-excited motor where field winding is connected in parallel to armature winding in order to supply voltage. Its name, “shunt,” alludes to how the field winding is associated in parallel with the armature winding. This setup permits the motor to keep an almost steady speed, independent of burden changes, making it an ideal decision for applications requiring consistent speed control.

DC shunt Motor

Definition of DC Shunt Motor

A DC shunt motor is an Electric Motor which is abbreviated as Direct Current Motor intended to convert electrical energy into mechanical movement.

Construction and Working Principles of DC Shunt Motor

The DC shunt motor development is equivalent to a DC motor . This motor can be developed with fundamental parts like field windings (stator), a commutator, and an armature (rotor). The functioning principle of a DC Shunt motor is, the point at which a DC motor is turned ON, then, at that point, DC streams all through the stator as well as the rotor. This current flow will produce two fields to be specific the pole as well as the armature. In the air gap among armature and field shoes, there are two attractive fields, and they will respond with one another for spinning the armature. The commutator overturns the armature current flow heading at standard gaps. So the armature field is repelled with pole field forever, it continues to spin the armature inside an equal direction.

DC-Shunt Motor Circuit Diagram

The DC shunt motor circuit outline is displayed below, and the flow of current and voltage being provided to the motor from the power supply can be given by Itotal and E.

In the event of the shunt wound DC motor , this current supply will divide into two different ways like Ia,& Ish, where ‘Ia’ will supply all through the ‘Ra’ resistance armature winding. Similarly, ‘Ish’ will supply through the ‘Rsh’ resistance field winding.

Along these lines, we can compose it as Itotal = Ia + Ish

We know that Ish = E/Rsh

In any case Ia = Itotal -Ish= E/Ra

By and large, when the DC motor is in a running state and the voltage supply voltage is steady and the shunt field current given by. In any case, we realize that the armature current is relative to the field transition (Ish ∝ Φ). Hence the Φ stays all the more in any case less steady, because of this explanation; a shunt wound DC motor can be named as a constant flux motor.

Back EMF in DC Shunt Motor

Whenever the DC shunt Motor’s armature winding rotates inside the magnetic field which is produced by the field winding. In this way an E.M.F can be stimulated inside the armature winding based on the Faraday’s law (electromagnetic induction). Albeit, as per Lenz’s law, the induced E.M.F can act inside reverse direction toward the armature voltage supply.

Hence, this E.M.F is named as the back E.M.F, and it is addressed with Eb. Numerically, this can be communicated as,

Eb = (ΦZNP) / 60A

Where ,

Φ = Flux for each pole within Wb

Z = No. of armature conductors

N = Speed of the motor (revolutions per minute)

P = no. of poles

A = No. of parallel paths

Speed Control of DC Shunt Motor

The speed normal for a shunt motor is different contrasted and a series motor. As a DC Shunt motor achieves its complete speed, then, at that point, the armature current can be directly connected with the motor load. At the point when the load is incredibly low inside a shunt motor, then the armature current can also be below. At the point when the DC motor achieves its complete speed, then it stays stable.

The DC shunt motor speed can be controlled without any problem. The speed can be kept up with steady until the load changes. When the load changes, then, at that point, the armature will in tends to delay, which will bring about less back E.M.F Consequently, the DC motor will draw additional current, this will outcome in improving inside force to gain speed.

In this way, at whatever point the load improves, the net consequence of load on speed in an motor is roughly nothing. Additionally, when the load decrease, then the armature accomplishes speed and delivers additional back E.M.F.

N α E_b ⁄ φ

N = K (V-I_a Ra/ φ)

It is clear from the above equation ,that the speed of a DC shunt motor can be changed by two methods.

The DC shunt motor speed can be controlled in two ways:

• Flux Control Method
• Armature Resistance Control Method

Flux Control Method

The flux control strategy depends on the principle that by varying the field flux ϕ, the speed of DC shunt motor can be changed.

DC Shunt Motor by Using Flux Control Method

N ∝ 1 /φ

In this technique, a variable resistance (called field rheostat) is associated in series with the shunt field winding. By expanding the resistance of the field rheostat, the shunt field current Ish can be decreased and consequently the field flux. In this manner, by the motion control technique, the speed of a DC shunt must be increased over the ordinary speed.

The flux control strategy is regularly used for the speed control of DC shunt motors since it is simple and modest technique.

Armature Resistance Control Method

The armature resistance control strategy depends on the principle that by varying the voltage available across the armature, the back EMF of the motor can be changed, which turn changes the speed of the shunt motor.

In this technique, a variable resistance, (controller resistance) is inserted in series with the armature. The speed of the DC Shunt motor is given by,

N α E_b

_Also,

E_b = V – I_a (R_a + R_C)

Consequently, because of the voltage drop in the controller resistance, the back EMF is decreased and subsequently the speed of the motor. The maximum speed that can be gotten utilizing armature resistance control strategy is the speed relating to RC = 0, i.e., the normal speed. Accordingly, by this method only speed below the normal speed can be obtained.

Brake Test on DC Shunt Motor

The brake test is the one type of kind test on the dc shunt Motor. By and large, this test should be possible for the low-rated DC machines. The fundamental justification for doing this test is to determine the efficiency and also by utilizing this test, the output of mechanical power can be determined and separated the same by utilizing electrical input. So this is the reason to work out the efficiency of the DC motor, this test is used. Accordingly, this kind of test can’t be utilized on superior-rated machines. So it is basically done for the load test on the motor or DC Shunt motor or it can be done for the low rated DC machines.

Characteristics of DC Shunt Motor

Some of the characteristics of DC shunt motor are:

• Improvement of Torque can be don with speed reduction.
• As the voltage supply is set then it works at a constant speed.
• This is upturned by the connections in the series motor.

Advantages of DC Shunt Motor

• High Starting Torque: DC shunt motors give high starting torque, which is fundamental for applications that require the motor to turn over under a heavy load, like lifts, elevators and a few type of crushers.
• Speed Regulation: DC shunt motors offer great speed regulation over many loads. They can keep a somewhat constant speed in any event, when the load differs, which makes them reasonable for applications where reliable speed is required, for example, conveyor belts and certain industrial machinery.
• Durability: DC shunt motors are known for their robust construction and durability. They can endure hard core tasks and offer long service life with proper maintenance.
• Simple Control: DC shunt motors are generally simple to control. By changing the voltage provided to the motors, you can vary the speed and torque output. This simplicity in control makes them appropriate for different applications.
• Smooth Operation: DC shunt motors offer smooth and calm activity, making them reasonable for applications where commotion and vibrations should be limited.

Disadvantages of DC Shunt Motor

• Limited Availability: DC shunt motors are turning out to be more uncommon in a ventures because of headways in engine innovation. Finding new parts or gifted specialists for upkeep can be trying in specific areas.
• Maintenance: DC shunt motors require more upkeep contrasted with a few different sorts of engines. Brush and commutator support is important to guarantee solid activity, and the brushes might should be supplanted occasionally.
• Brush Wear: The brushes and commutator in DC shunt motors can wear out over the long haul, prompting expanded upkeep expenses and margin time. Brush wear likewise restricts the most extreme speed of the motors.
• Limited Efficiency: DC shunt motors are less proficient than a few different kinds of engines, for example, AC enlistment engines. This lower proficiency can bring about higher working expenses, particularly for nonstop obligation applications.
• Size and Weight: DC shunt motors will quite often be bulkier and heavier contrasted with a few present day options like brushless DC motors. This can be a detriment in applications where space and weight are basic variables.

Applications of DC Shunt Motor

• Industrial Machinery: DC shunt motors are many times utilized in modern hardware, including transports, blenders, siphons, and machine devices, where exact speed control and high starting torque are required.
• Elevators and Lifts: DC shunt motors are well-suited for lift systems, giving the essential high starting torque and smooth control for vertical transportation.
• Cranes and Hoists: Cranes and Hoists frequently use DC shunt motors in light of their capacity to deal with weighty loads and give exact speed control, which is pivotal for material taking care of hardware.
• Rolling Factories: DC shunt motors are utilized in moving plants to drive the rollers that shape and cycle materials like steel and aluminum. Their great speed guideline guarantees steady item quality.
• Print machines: DC shunt motors are utilized in print machines for controlling paper feed and print head development because of their capacity to keep up with steady speed under fluctuating loads.
• Textile Industry: DC shunt motors track down applications in the material business for driving winding around and turning machines, where exact control of thread tension and speed is basic.
• Paper Factories: DC shunt motors are utilized in paper factories to work hardware for cutting, rolling, and molding paper because of their solid exhibition and speed control.

Solved Example of DC Shunt Motor

A 240 V DC shunt motor having an armature resistance of 0.3 Ω carries an armature current of 40 Amps and runs at 600 RPM. If the flux is decrease by 15 % by the field rheostat. Find the speed of the motor expecting the load torque remains the same.

Case 1:

N₁ = 600 rpm, I_a1 = 40 Amp

therefore, E_b1 = V – I_a1R_a

= 240 – (40 x 0.4)

= 224 Volts

Case 2:

12% reduced in the flux

(Phi₂)Φ₂ = 0.85 ₂

(Phi₁) Φ₁ / (Phi₂)Φ₂ = 0.85

since the load torque is given to be constant,

(Phi₁) Φ₁ I_a1 = (Phi₂) Φ ₂I_a2

I_a2 = (Phi₁) Φ ₁ / (Phi₂) Φ ₂ x I_a1

=1 / 0.85 x 40

= 47.05 Amps

therefore, E_b2 = V-I_a2R_a

=240- (47.05 x 0.4)

=221.18 Volts

therefore, N₂ / N₁ = E_b2 / E_b1 = (Phi₁) Φ ₁/ (Phi₂)Φ ₂

N₂ = 221.18 / 228 x 1 / 0.85 x 600

N₂ = 696.99 Rpm

Conclusion

DC Motor was used widely because of its flexibility and reliability. This motor gives highlights like simple turning around control, speed guideline, and it is low to begin force. Hence, this motor can be utilized for belt-driven applications inside auto as well as modern applications. The DC shunt engine remains as a demonstration of dependability, flexibility, and persevering through prominence. Whether you are in a modern setting, driving a conveyor belt, controlling the speed of a rolling mill, or essentially changing the volume on an old stereo system, odds are good that you’ve experienced a DC shunt motors at work.

FAQs on DC Shunt Motor

What is a DC shunt motor?

A DC shunt motor is an electric motor that sudden spikes in demand for direct flow (DC) and has an equal (shunt) field winding and an armature winding. It’s known for its capacity to give great speed regulation and high starting torque.

How does a DC shunt motor work?

A DC shunt motor works on the standard of electromagnetic enlistment. At the point when current courses through the field winding (shunt winding), it makes an attractive field. At the point when current courses through the armature winding, it interfaces with the attractive field, making the armature pivot and create mechanical output.

How is the speed of a DC shunt motor controlled?

The speed of a DC shunt motor can be constrained by fluctuating the voltage provided to the motor. Diminishing the voltage lessens the speed, while expanding it raises the speed.

Are DC shunt motor still generally utilized today?

While they are more uncommon in an applications because of progressions in motor innovation, DC shunt motor are as yet utilized in unambiguous enterprises and applications where their qualities are beneficial.

What are the critical contrasts between DC shunt motor and different kinds of motors, for example, AC motors?

DC shunt motor vary from AC motors as far as power supply (DC versus AC), speed control strategies, and starting torque characteristics. AC motors are in many cases more effective however may not offer a similar level of speed control.