Solenoid Engine

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In automobiles, engines are the primary source of producing energy by producing combustion heat with which chemical energy is converted into mechanical energy. Combustion produces harmful gases, which contribute to environmental pollution. Thus, electric bikes were introduced, but they can not carry much load and are not suitable in the long run. 

That's where electromagnetic engines step in, which provide more power and capacity but without the harmful air polluting gases. Solenoids are a long coil of wire wrapped in many turns generating a uniform magnetic field when current is passed through it, just like a bar magnet. One can find the applications of solenoids in many solenoid engines as these coils can be strengthened by adding an iron core.

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This article will explain to you how to make a solenoid and what is the use of solenoid engine by telling you the application of solenoids as a solenoid motor.

Properties of a Solenoid

  • Solenoids are used a lot in switches since they can convert electric current into mechanical action.

  • The density of coils, number of turns, and the current inside a solenoid determine its magnetic fields.

  • The uniform magnetic field in a solenoid is at the center of the long solenoid.

  • The fields outside of the center are weaker, and the magnetic field lines are further apart.

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  • The force with which a ferromagnetic rod placed near a solenoid is pulled towards it as roughly given by determining the change in magnetic field energy when the rod is inserted into the solenoid:

Force on rod = change in the magnetic field energy/distance moved by the rod within the solenoid.

  • Even a small Solenoid can exert a force of a few Newtons.

What is a Solenoid Engine

A solenoid engine works on the law of electromagnetic attraction. Coil magnetism attracts the plunger, and a spark distributor is used to cause the electromagnet to move as per the position of the piston without the use of sensors or microcontrollers. When an electric current is supplied to the conductor, a magnetic field is set up at its surface. This magnetic field acts as an electromagnet. The electromagnetic force produced is dependent on the current inside the coils and the number of turns in the coils. 

How to Make a Solenoid Engine

You would need the following materials to make the solenoid

  • Plastic drinking straws

  • Electrical tape

  • 2m thin insulated wire (using size 32 magnet wire gives best results)

  • 1.5 V battery either AAA or AA

  • A wire stripper or sandpaper

  • Steel needle

  • Optional

    • A steel nail with a flat head that can go inside the straw

    • A strong disk magnet (rare earth)

Making the Solenoid Engine

1st Step - Create a coil

  • Cut a straw of 10 cm in length.

  • Wrap sellotape from the bottom a little way up leaving about 15 cm long tail unwrapped.

  • On the taped part of the straw, wind 100 tight and neat coils of the wire, one layer at a time.

  • Ensure that you are always coiling in the same direction.

  • Leave the 15 cm tail uncoiled.

2nd Step - Connect the battery

  • Form a T shape with the battery and the taped end of the straw by taping the battery on the end part.

  • Use sandpaper or wire stripper to remove some insulation from the wire.

  • Now tape one of the wire’s ends to the taped battery and leave the other end loose.

  • You need to ensure everything is tidy at this step since the next step is a little tricky.

3rd Step - Adding the plunger and testing it

  • Hold the straw a little above the table in an upright position.

  • Slip the needle into the straw, point up. You could either place the needle on the table or place the head of the nail on the magnet and put it in the straw that way.

  • Now touch the exposed end of the battery with the loose wire, the nail plunger or the needle should shoot up inside the wire.

Application of Solenoid

  • The main use of solenoid is as a switch for power. They are used in inductors, valves, antennas, etc. Its application is in varied fields like medical, industrial use, locking systems, automotive, etc.

  • It is used to control a valve electrically.

  • They can be used in a specific kind of door locking system. These locking systems are very secure as they use electromagnets.

  • They are used in computer printers.

  • Solenoids are used in fuel injection gears in cars.

Advantages of Solenoid

A solenoid has many advantages that you can not find in an ordinary coil:

  • By using a solenoid engine in automobiles, there is zero pollution in the air.

A solenoid engine can work efficiently with less torque.

  • Solenoids react immediately when electricity is applied to them.

  • Solenoid engines can be used as a substitute for fossil fuel.

FAQ (Frequently Asked Questions)

Q1. What are the Different Types of Solenoids?

Ans: The types of Solenoids in the market differ in their design, material, and function. But all of them are based on the same electrical principles:

  • AC laminated solenoid - The amount of force performed by an AC solenoid in their first stroke is what makes them famous. They produce a clean buzz when they are in use, and they come in different configurations and ranges. An AC solenoid can use a stroke that is longer than a DC solenoid.

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  • DC C-frame solenoid - In a DC C-frame solenoid, there is only a frame in the shape of the letter C, covering the coil. They are mostly used in a DC configuration but can also be applied in AC power.

  • DS D-frame solenoid - In this, there are two pieces of frames covering the coil. They are used widely in industrial applications. These solenoids can also be designed for AC alternatives. 

  • Linear solenoid - These solenoids can use a pulling and pushing force on mechanical devices and are utilized for metering tasks. These are the most common solenoids and are used in starters of vehicles that have a motor. When an electrical force is applied to these solenoids, they move linearly to get two contacts together. This allows power from the battery supply to flow into different parts of the automobile, which will then start it.

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  • Rotary solenoid - This solenoid is used for purposes where an easy and automatic control process is required. It is the most robust solenoid amongst all types of solenoids. They were designed for defense mechanisms, but now they can be found in many automated industrial processes like a shutter, laser, etc.

Q2. What is the Formula for the Magnetic Field Inside a Solenoid?

Ans: The magnetic field inside a solenoid depends on the current and the number of coils in it. The magnetic field does not depend on the diameter of the solenoid, and the field strength is constant inside it. Ampere’s law can be applied here to calculate the magnetic field:

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The magnetic field inside the solenoid has a uniform value B and outside it is 0. If there are n turns per meter in the coil then :

Ienclosed = I(n * L), where L is the length of the rod.

Taking the integral we get: ∮ B^. ds^ = BL + 0 + 0 = BL.