Some improvements in construction of homebrew electromagnets and inductors

Above is a typical home experimenters construction of an electro magnet usually consisting of a soft iron bolt six inches in length and approx 1/2 inch in diameter. and usually available from a hardware store.

The bolt has a screw thread and two insulated metal washers to hold the windings in place and a nut covering the screw thread.

The winding consist of 20 swg insulated magnet wire although any gauge wire could be used for this purpose.

Check your electronics or electricity store (Radio Shack ) to get some magnet winding wire.

I used a twelve volt car battery to provide power to the electromagnet and in this case also any DC power source could be used.

The amount of current and voltage needed to energise an electromagnet varies with wire size and length and will have be to be determined by experimentation by yourself and your friends.

If you can get some wire resistance and power values for your wire gauge you may be able to determine the power required to power your magnet.

I afraid this is outside the scope of this article and I encourage you to experiment yourself but on no account use the AC power from your home utility power supply apart from being the wrong type of power (AC) is can also be deadly if you don't know what you are doing (SO BE WARNED).

Please note the iron bolt should have a layer of insulation wrapped around it to prevent a possible short circuits and to hold the washers in place

The winding wire for a normal electromagnet is wound around the from the bottom to top in a circular pattern around the metal bolt and when the top is reached ,I then use some common sticky cellotape tape to hold the layer windings in place and then wind down towards the bottom .

I repeat the above processes until sufficient wire and layers are wound on the bolt core for the magnetic strength required..


A more stronger electromagnet

Using the same components as the description above , I believe from experiments I have carried out, I can make a small improvement in the strength of the induced magnet field in a magnetic metal bolt for example assuming of course the same amount of power and core winding wire and then obtaining a more stronger electromagnet But the only way to convince yourself is for you to the perform an experiment and test it for yourself .

All instruction as to first diagram above apply

but with the exception that when the top of winding is reached ,the winding wire instead of being wound to the bottom in several turns only one turn is required to bring the wire to bottom ,where you once again tape it in place and repeat winding to the top again until sufficient turns and layers of wire have been added to the core.

Please remember all downward windings are of only one complete loop as illustrated above.

If you care to repeat my experiment I believe you will notice a stronger electromagnet with the second design.

Making an Permanent Magnet

This a simple excellent design for making permanent magnets or magnetising tools such as screw drive,tools etc.

The device consists of a double ended screwed casing such as galvanised domestic water piping ,I used one inch tube and about four inches in length.with one end cap as shown in above drawing.

Please note the outer tube must be able to be magnetised so don't use copper or plastic piping..

You will also need to make a coil winding on a hollow cylinder that will fit and then be able to be insulated from the outer metal casing.

I made a hollow cylinder by wrapping and by placing some paper glue all over some A4 paper and then wrapping it around a piece of wooden dowel of suitable diameter. Remove the paper cylinder when the glue is dried and the paper is hard. It may be a good idea to leave some space between the start of the paper and wooden dowel so that the paper cyclinder can be easily removed There may be other methods to create the former such as using pvc piping ,if you can get suitable metal casing that will allow the pvc to to fit iside the magnetic metal outer casing with the winding.

You could use insulating tape over the outer coil winding or even wax to make sure no electricity is able to be transferred from the coil magnetising windings to the metal casing when placed inside the metal pipe and thus shorting out the magnetising device.

It may be a good idea also to vanish your coil winding ,as this aids in the insulatation and holds the coil windings in place.

Put the device together as shown in illustrations

The way to make a permanent magnet is to place the metal object to be magnetised in the centre of the coil wound solenoid and then you use a short burst of high current to power up the coil and then switch it off again rather quickly.

Please note the higher current value you can use the better ,a charged capacitor arrangement is ideal and could be used to provide the high current for a short period when it is discharged into the coil.

A high current diode may be needed in this circuit to prevent the reverse EMF from de magnetising the metal subject.

The windings are wound in the same direction as for a normal solenoid winding.

By the way this design could also be used as a excellent solenoid actuation switch with the addition of a return spring.

Again you will need to experiment with the metal casing ,coil length ,wire gauge sizes and power to get the desired the magnet strength.

It just occurs to me that if you installed the central coil and make two drill holes in one of the end caps to take the leads from the coil ,you could then insert a metal object to be magnetised in the hollow solenoid coil, and then place a second end cap at the other end of the metal cyclinder..

So that when the current is introduced to the coil all the magnetic field generated would need to then travel through your metal sample and around the metal casing thus making a stronger magnet than using a single end cap as illustrated. below.

Remember you cannot magnetize any other object stronger than the applied magnetic field.

Similar arrangement to the first magnetiser but please notice the one return loop in each top bottom arrangement.

This also gives a better magnetising field as well I believe.

I haven't tried this idea as shown in following section, but I also think a slight improvement may also be noticed in operation. But at this stage have no way of confirming it as we are dealing with AC not DC as of the top electro magnets designs . Other's who are more experienced in the art may be able to help me here.

Above is a typical metal laminated transformer consisted of E shaped metal cut out with an I shaped metal filler to complete the magnetic circuit.

The coil is wound on a plastic former divided into two separate winding sections namely primary and secondary output coil windings.

The winding former is placed in the center of the metal arrangement.

The power is applied to the primary circuit windings and is either outputed at the same power levels ( voltage current ) or used to either step up or step down the voltage or current levels.

I believe it would be interesting to observe what would happen if the below arrangement was considered and wound in accordance with modified coil winding arrangement as put forward in the previous two ideas.

If you do construct one please don't forget to let me know what your observations are.

A Magnetic Bearing idea for a Adam type Motor

If you look at the diagram you will notice a central plastic or non magnetic rotor onto which are mounted a collection of rectangular magnets at regular intervals . The magnets I believe are common to Radio Shack or Tandy.

All magnets are positioned that is all outward facing magnet poles are the same, all North or all South.

Six magnets I believe would be ideal although a bigger rotor would require more.

The rotor is driven by a current impulse in a modified single pole direction electromagnet (North in this case ) mounted on the outer side and close to the rotor which is fired from an impulse generated into a modified pick up coil and amplified via a transistor arrangement from the opposing side of the rotor

Please note both the pickup coil and the driving electromagnet wound as in a modified design as previously described above. .

see articles on a Magnetic gyro and Lenz motor

The positions of electromagnet and pickup coil shown are for ease of drawing and may not be the best position possible.

Again looking at the diagram you will also see 1 inch round magnets at each end of the driving shaft

( The magnets desired are 1 inch round Tandy Radio Shack the ones with a central hole )

A magnet is mounted at each end of the rotor axel and is in opposition to one facing it on the permanent fixed magnets on brackets at each end. ( that is North opposing North or South opposing South )

The diameter of the axel needs to be small enough so that ends are able to rotate freely inside the opposing magnets.

Although only a single magnets are shown in the diagram there is no reason why several could not be used to increase opposing magnetic strength..

At start up the axel at both ends although in opposing mode are resting on each end bracket magnet bottoms due to the combined weight of the magnets themselves the axel and rotor weight combined.

When power is sent to the electro magnet The rotor will begin to spin and the rotor assembly should lift and a find a point of balance on the opposing magnet. fields

The unit is now spinning on magnetic field cushion .

The device may at this stage have no practical value as yet but it would be interesting to watch and ponder any way. Search made Simple

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