Questions tagged [electromagnet]

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Control 12V relay by using Arduino

I have an Arduino Mega, 12V relay module, and 12V external power supply. I want to control relay state (on/off) by using Arduino I/O pins (5V). Is it good idea to use following simple diagram? There ...
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1 vote
83 views

Snubber circuit for electromagnet

I have run into the same problem described here and here, when I added diode to electromagnet. Basically, the magnet still holds with about 20kg force several minutes after removing power. The ...
• 10.3k
2k views

How do I build an electromagnet?

I want to make an electromagnet that can lift a paper clip off of the ground from a short distance (probably 7 to 8 inches). I naively thought of making an electromagnet as a simple task (because of ...
• 99
34 views

Briefly Drive Permanent Electromagnet [duplicate]

I need to drive a 12VDC/1.2A permanent Electromagnet for 2 seconds (to release object). Will the attached circuit be able to do that or do I need something else? Thank you https://imgur.com/wxmRo7w ...
52 views

Possibility of achieving magnetic levitation(Arduino) with just one solenoid and a ring magnet?

I am currently working on a magnetic levitation project and have been looking into all types of magnetic levitation. One particular video I found around the subject was this: https://www.youtube.com/...
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1 vote
54 views

What are the components I would need for an electromagnet with the given specifications?

I need to make an electromagnet that exerts at least 5 times its own weight on a ferromagnetic material kept 0.03 m away. I know that: F = [(number of turns × current)2 × magnetic constant(4 × pi × 10-...
94 views

How do I make an electromagnet that weighs less than 2 kg but can exert a force of at least 420 N

For a project that I am doing currently I will need an electromagnet whose total weight is less than 2kg, but can exert a force of at least 420 N on a ferromagnetic material 0.03 m (3 cm) away from ...
1 vote
47 views

Is there any effect on efficiency of electromagnet if winding wire cross each other during winding?

While winding a core of the transformer some turns cross other turns. Will this affect the magnetization produced by the core?
73 views

Determine inductance of large inductor

I asked a similar question before but i am still struggling with this problem. I am trying to measure the inductance of a large (34cm diameter) electromagnetic brake. Important findings to keep in ...
• 209
1 vote
70 views

Why don't Li-pol accumulators change the polarity of an electromagnet?

I made a simple electromagnet with a screw and a wire. When I supply power to it via 1 AA battery (1.5v) and change + and - contacts it acts differently with other magnets (attracts and repels), but ...
68 views

How to determine electromagnet air-gap using current waveform

I am trying to determine the air-gap of between an electromagnet (coil diameter 34cm) and a metal armature using the current waveform. In the figure below you can see the charging curve of the coil ...
• 209
1 vote
117 views

Determine electromagnet inductance

I am trying to measure the inductance of a large electromagnetic brake (coil diameter 34cm). I used two methods: LCR meter (100Hz because the brake is activated using a rectified 50Hz AC voltage) (...
• 209
1 vote
167 views

Determining an industrial electromagnet coil's number of turns and wire diameter, etc

I'm a new graduate and fresh hired Electrical Engineer who works in a company building magnetic separators for general industry (including mining, recycling etc.) Normally, we build magnetic ...
46 views

Preventing a circuit from blowback voltage from an electromagnetic coil [duplicate]

I've connected up the coil of a relay to a transistor, which is in turn connected to an Arduino Nano. The circuit is a timed relay switching circuit. I know that when the current to an electromagnet ...
113 views

How does this electromagnet control circuit work?

I am reverse engineering an electromagnet control circuit in isolation (I do not have the original controls or wiring diagram). I believe applying 12VDC should trigger the respective magnets, but it ...
308 views

Ideal dimensions for an electromagnet?

I've been working on a design for an electromagnet. I've exprimented various lengths of core, and figured the height of the windings for 6 different gauges of magnet wire based on the maximum current ...
144 views

What maximum DC current and maximum voltage can I flow through an inductor?

I have built a toroidal inductor by wrapping an insulated copper wire over a toroidal laminated soft-iron core. The dimensions of core and copper wire are as below: Toroidal core: Inner diameter = 20 ...
44 views

Problem with Amp Turn calculations for electromagnet

I'm attempting to design an electromagnet, and the equations seemed to produce an nonsensical result. The electromagnet needs to impart 42.75 newtons at 0.0015875 meters. I needed to discern the Amp ...
105 views

Powering an electromagnet

I'm a first time question asker... So here's the problem: I need an electromagnet so I made one out of an old microwave transformer. (something like this: https://www.instructables.com/Microwave-...
79 views

Turning a transformer into an electromagnet [closed]

I saw in a YouTube video that people turned a transformer into an electromagnet by rearranging the T-shaped metal. When I did the same and plugged it into the AC supply, it gets too hot. I tried ...
314 views

Ferrite core in electromagnets

I have a small project based around designing a small home-made DC actuator using a small DC electromagnet. My final goal is to generate the strongest magnetic field possible with the minimum amount ...
1 vote
37 views

Solenoid Train - Best approach for magnetically guiding an object along a path?

My project is to pull an object along a path with solenoids, by cycling their on/off state. I don't know if ferrous core solenoids pulling steel would be more efficient than pulling a neodymium ...
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101 views

Will a regular neodymium magnet attract an electromagnet not currently being supplied with power?

I have a setup for one of my robotics projects where a neodymium magnet is placed across from an electromagnet. I power the magnet with DC through a L298N motor controller that is connected to an ...
48 views

Does electric resistance of an iron-cored electromagnet depend upon the size and type of the core?

I know that the resistance of an electromagnet depends upon the nature, length, and diameter of the wire. Is it also depend upon the size and nature of the iron core on which the wire is wrapped?
579 views

Reducing Residual Magnetism in Electromagnets

My issue is that after the electromagnet has been switched off, the magnet and the test steel C45 object attracted to it remain attached. The residual force appears minimal, as no object which was not ...
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1 vote
158 views

How many volts is needed to power a coil

I recently encountered and was trying to troubleshoot a device that's not working properly. In tracing the functionally of the device, I isolated the issue with a coil that does not activate. ...
• 111
101 views

Electromagnet with a pipe as the core

I have heard that applying a strong magnetic field to diesel fuel can positively affect the filtering out of microbial contamination. Assuming that is true: I thought it would be simple to wrap a ...
2k views

Just for fun, I decided to build what I was hoping would be a relatively powerful electromagnet. I used this copper wire (20 AWG, entire 1 pound spool) and this soft iron core (0.5 in diameter, 6 in ...
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74 views

PWM driven MOSFET to power a coil

I need to power a coil (electromagnet to be precise) using a PWM singal generated by an arduino or a 555 timer. I can esily power the coil when the PWM signal is in the HIGH (5v) state using a simple ...
61 views

Electromagnets and voltage

I'm thinking of getting two electromagnets. On Amazon, it reads 24V 400N. What does that mean? Of course, it would be DC since that is what electromagnets are based on. I will use a simple series ...
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482 views

MOSFET Drain - Source Current limiting

I am a new enthusiast to MOSFETS. I am trying to use a MOSFET to switch on and off a electromagnet that draws 5 amps at 1.2 volts using an Arduino. The circuit I am using has a diode going from the ...
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185 views

Solenoid : how dimensions ratio affects the magnetic field?

For a constant length of copper wire (with constant diameter), how can I calculate the most efficient solenoid diameter/length ratio ? (i.e. what ratio produces the strongest magnetic field, if the ...
1 vote
246 views

How to design a solenoid.?

I want to design a DC solenoid valve that could compress a spring under 5 kg of load. All I know is the voltage (12V), load (5kg), the current range (15-20), and the cross-sectional area of the ...
244 views

Use DC Motor driver for electromagnet

I need to control the force exerted by an electromagnet using an MCU. it's not a commercial item so I don't have any datasheet. Here what I know: resistance: 8,9 ohm may be powered up to 60V (with ...
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65 views

Inductor/Electromagnet used to lift up a magnet? Joules to Newtons or Joules to Gauss?

With interest in using an electromagnet to lift up a magnet. I dove in. I will state general information. The set up is unknown but I'm interested in the physics/electrical engineering involved in ...
45 views

tip3055/2N2222 coil steering

i want to switch an electromagnet with a 2N2222 & TIP3055 switching should be triggered by a coil passing a magnet as optcal would be to slow can anybody assist or give us some advice. we don't ...
54 views

Building a pseudo-solenoid electromagnet - Heat disipation

I am planning to build an electromagnet as shown in the picture below. The copper windings are coiled around a thin plastic cylinder. The goal of the setup is to attract small metal chips floating in ...
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1 vote
81 views

Driving an electromagnet for 10 seconds without overheating the coil

I have the following issue that I would like to discuss. I have an electromagnetic lock based on an electromagnet rated at 24V/44 ohms and a PSU at 24V. Basically, you apply a voltage at the coil and ...
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2k views

LEDs keep dying in 12v circuit with powerful electromagnet

I have a circuit like this: 12V/2A DC input. A small blue LED with a 2.2k resistor in series. A powerful electromagnet with ~40ohm resistance in parallel. It is possible the electromagnet has more ...
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121 views

Is it dangerous/harmful to increase the voltage supplied to a 12v electromagnet?

I have a 12V-rated electromagnet which I bought online. As it isn't strong enough for my needs, I tried applying a higher voltage (~20V) which did make it stronger. It does get a bit warmer after a ...
45 views

Variable Turn Density Solenoid

I am working on a medical device application and would like to use a solenoid with a variable turn density such that the force $F$ on a metal piston within the solenoid cylinder is not constant but ...
354 views

Where to purchase the iron core for an electromagnet?

I want to build a strong elctromagnet. The design is very intuitive and simple, shown in the above figure. The metal core is in a cylindrical shape. The current design is 100 turns and 30 Ampere, with ...
34 views

What device to power 4 directional coils to rotate magnetic field

I am trying to make a solid state device that creates a magnetic field applied on an sample that can control the field direction and strength. My current design uses a 8 coil stepper stator that has ...
36 views

NMOS to control electromagnet

I'm using a 3.3V output from a pmod port on a digilent Basys3 board. I have the circuit working IRL but I am required to provide a diagram and simulation. I'm not proficient in LTSpice and not 100% ...
3k views

Why do I need to remove a part of the insulation on a copper wire on a simple electric motor?

Why do I need to remove a part of the insulation on one end of a copper wire in making a simple coil electric motor? How does removing only a part of the insulator makes the motor spin freely? ...
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139 views

Why does the voltage drop when powering, then reverse when disconnecting this electromagnet?

I've just bought a 12V 260mA electromagnet and I have some questions about it I don't know why, but when I connect electromagnet, my 12V power source (9V and 2 1.5V AA batteries in series) drops to ...
181 views

Half H bridge to drive electromagnet

I want to control the current on an inductive load (electromagnet) by the means of PWM switching. I have done some research and saw a lot of different circuit configurations. The electromagnet will ...
2k views

What happens if the secondary of an ordinary transformer is left open?

Let's consider a transformer. The ideal transformer equation is: $$\frac{V_1}{V_2} = \frac{I_2}{I_1}$$ Suppose the secondary is open (that means $I_2 = 0$): it will result $I_1 = 0$. How is this ...
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63 views

Circuit giving values on both AC and DC

I have a generator stopper which works on 220 volt AC (in India 220 volt AC is normal supply) and has an electromagnet which pulls up a lever and the generator is stopped. It works perfectly when the ...
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