# Questions tagged [induction]

Induction is the process by which the electrical or magnetic state of a body is influenced by the action of electrical or magnetic fields by proximity without contact between a “source” body and the influenced body.

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### Uneven current sharing between four parallel cables [closed]

We are performing testing of an induction furnace where the power is supplied through diode based rectifier - half bridge inverter setup to the tank circuit by means of two sets of four 2 feet long ...
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### electromagnetism and earth field [closed]

Can we generate sufficient Electricity to power household gadgets from the experiment shown https://youtu.be/qedhViY72f8?si=lB5shkVdofsKVhd_
1 vote
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### how do the capacitors affect the performance as a generator of a permanent magnet, brushed DC motor

I have a 24V 24A brushed DC motor(from a old pump so quite big in size). it has permanent magnets on around the coils, and the coils are wound around iron. just like many brushed DC motors it has ...
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### Induced EMF in a stationary coil

Suppose a there is a coil which hasvelocity=0 and we can say it does not experience any force due to themagnetic field. There is no role of induced EMF in any case. If we place a stationary coil and ...
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### Is magnetic flux in a transformer proportional to voltage or current?

Consider a transformer. I put a constant sine wave AC voltage through the primary circuit and a resistor on the secondary circuit. I know that the secondary voltage is proportional to change in ...
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### How basic wireless electricity transmission circuit works?

In the circuit below because of the DC voltage source there will be no flux change on steady state of the circuit so how the LED still stays turned on if magnetic flux is not changing and no ...
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### What does resonance means in inductive coupling? [closed]

From what I understood: resonance helps achieve higher coupling coefficients in coils. What does it mean and how is it achieved?
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### Easiest way to detect objects using DIY materials

I want to build a Scrabble board that detects tiles placed, mainly as a one off challenge and learning experience (i.e. not a commerical product). I haven't started building yet: I'm trying to work ...
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1 vote
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### In the perfectly coupled transformer, there is no voltage induced in the primary due to the loaded secondary?

When the coils of a transformer are perfectly coupled, the equations include only the self induced emf in the primary and the mutually induced emf in the secondary. However, when speaking of loosely ...
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### EMF induction in a coil placed in a variable magnetic field

Consider a conducting coil placed in a variable magnetic field. By the laws of nature, an EMF will be induced in the coil. Between which two points is the EMF induced in the coil? If we consider it to ...
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### stator current in induction motor when load increases

When the load increases the speed of the rotor decreases and so the relative speed of the rotor and the magnetic field of the stator increase (slip increase). As a result, the induced emf will ...
49 views

### Induction motors torque measurement

I am to calculate the running efficiency of a 3-Ph squirrel cage induction motor. I have the rated data for the motor. I have the load speed of the motor but I need output torque to calculate the ...
2k views

### Why does a 1:1 transformer preserve voltage?

In the context of transformers, it seems intuitively obvious about winding ratios; for example doubling the coils on the second winding doubles the voltage. But this seems to skip over the question of ...
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### Example problem of induced emf in a coil rotating in the earth's magnetic field

I just recently learned magnetism-coil-faraday's law and I want to do some real world problem solving. Question: Let's say a copper wire coil (20 mm dimeter (r=10 mm)) of 3 turns (N=3) is on the ...
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### How do transformers work?

I am a recent EE graduate and never really understood how transformers work. I am having trouble understanding how voltage is increased at the expense of current in a step up transformer. I understand ...
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### Would the inductor have an inductive reactance due to mutual induction via an AC source?

In a setting like that in an ideal transformer. An AC source connected to the primary induces an AC voltage in the secondary. Would the secondary coil have an inductive reactance in this process?
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### Equivalent Circuit of Induction Motor

To find the equivalent circuit of the rotor side of an induction motor, the resistance and the reactance changes to ensure that the current in the rotor remains the same, whilst removing the slip term ...
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### Is the communication between transponder car key and car digital or analog? [closed]

I am surprised to not find much info on-line about the technology and communication technique that car immobilizer systems use to communicate with the transponder key. To be more specific, my 2001 ...
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### Why can domestic induction stoves heat aluminium tape, but not aluminium pans?

Domestic induction stoves can't be used with thick aluminium or copper pans, but when I try to heat aluminium tape it does get hot. Can someone explain why this is the case?
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### LC Resonance with Inductor with Solid Metal core

Consider inductor with air gap and solid metal core made from material with relative magnetic permeability 1 regardless of temperature (such as copper or aluminium). There is Air gap between coil and ...
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### Can I tap the hot wire leading to stove hood vent fan to power a low current LED warning bulb by mean of induction?

I cannot hear the hood vent fan running and I waste a lot of electricity. I know about lighted fan switches but they are not always found in every stove hood. Mine has no lighted fan switch. I use the ...
480 views

### Can a 3 phase Induction (squirrel cage) motor generate electricity?

I am thoroughly confused again. I am at the point of relegating electricity as a black box, a mysterious phenomena I'll never comprehend. I just saw a YouTuber build an elaborate water mill for ...
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### 3 phase induction hob, single phase wiring [closed]

While installing this 3-phase appliance I came across these diagrams which have been bugging me a bit, therefore it would be nice to find out what is the correct way to wire this up and what is the ...
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### Why does one MOSFET heat up very fast compared to the other MOSFET in this induction heater circuit?

simulate this circuit – Schematic created using CircuitLab I'll start off by saying this project is just an experiment I'm playing around with and is not the typical ZVS design you find ...
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### Electromagnetic Energy Harvester

It was suggested I make a new post since the topic was growing in complexity. I am looking into constructing an inductor to utilize electromagnetic induction near a high voltage transmission line. If ...
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1 vote
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### Why doesn't the cross section of a material affect flux density?

I am trying to design an inductor. I have free hand of using any geometric form and ferromagnetic material. It's my first time doing it. I studied magnetics design in college and I always thought that ...
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### H-bridge inverter with phase shift control

I am trying to apply phase shift control to my H bridge inverter but I get these spikes in the picture I don't know why. And it getting worse if I apply inductive load
1 vote
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### How does EMI from power cables affect analog signals in audio cables and digital signals in cables like Ethernet/HDMI/etc?

This question is for all those home theater and computer specialists out there. How does EMI from power cables affect analog signals in audio cables and digital signals in cables like Ethernet/HDMI/...
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1 vote
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### 3-phase induction motor starting current calculation

I'm trying to calculate the starting current of a motor (460 VAC @ 60 Hz) using the datasheet information I shared. Am I suppose to use the ratio given under "starting values" for current? ...
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### Multiple 240v AC LED indicators cross-talk

I have these 230V AC indicator LEDs, which I'm using in a project to indicate when I have various switched circuits live. Due to space constraints, the switched lives of these LEDs are routed through ...
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### Does winding a solenoid around a copper pipe reduce the net magnetic flux at all?

I want to wind an air core solenoid around a copper tube. One end of the solenoid is soldered to the copper tube. (See picture above). Will a magnetic field be induced in the copper tube that cancels ...
1k views

### Why we use constant value of magnetic flux in transformers

I have a confusion regarding the formulas of the transformer. I have seen in many places people using a constant value of the flux B in the transformer equation: turns per volt=1/(1.44 x Bmax x A x f)...
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### Did I wire this AC motor properly?

I disassembled a drill to replace the chuck and when putting it back together it seems to be short-circuiting. I have doubled check the cables but they seem to be ok, so I'm afraid I may have wired it ...
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### Best switching topology for axial stator with rotating field

The idea is to have a stator with coils driven by AC current not switched with DC as is done in most cases. On top of that I need the field to physically rotate around with the rotor. This essentially ...
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### Want someone to review my Helmholtz coil design to see if I am missing something obvious before I fabricate it?

I am planning to construct a Helmholtz coil and wanted electrical engineers to take a look just so I know I am not overlooking anything. The max field strength I am looking for is 200 Gauss. I ran ...
2k views

### Can wireless charging become more energy efficient?

I've stumbled upon a few articles saying that wireless charging takes more energy to charge something compared to the cable. Like this one. Like in the test from the article, it takes 47.33 % more ...
280 views

### Why doesn't an induction heater and an induction ring launcher produce the same effect?

I want to know why an induction heater and an induction ring launcher don't produce the same effect. Both seem to use AC voltage to power a solenoid(which induces a voltage in a pipe) so why doesn't ...
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1 vote
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### Phase splitting principle of single phase induction motor

How two sinusoidal flux 90 degree out phase creates a rotating flux? In particular if A = sin(wt) and B = -cos(wt) are two flux produced in a single phase induction motor. Then their resultant would ...
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### How does the floating light bulb rotate and power off? [closed]

I am trying to understand on a high level, how famous floating light bulb actually works. https://www.floately.com/products/volta-light-bulb I kind of understand how it floats and how it is supplies ...
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### I am winding a large induction coil but ran out of wire and need to solder or connect more wire to the existing wraps, how best to do this?

I'm winding a 6" coil with 16ga magnet wire. I want about 1600 turns but ran out of wire. What is best way to add more wire w/o creating a problem at the join, such as over-heating or creating ...
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1 vote
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### Total newb trying to build a wireless power transfer system for terrarium water pump

I am needing to build a induction based wireless power transfer system that I can use to power a small aquarium pump through the glass base of a very tall vase. I have been researching this for about ...
158 views

### If the impedance of two coils is measured to be identical at 250.0 kHz, is it safe to assume identical impedance across the spectrum?

This question pertains to matching two air-gap inductors for use in resonant coupling. Alternative solutions are welcomed and appreciated. The two coils shall be comprised of identical wire. The two ...
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### According to my understanding, this induction heater should be melted, but it's not. Why not?

I opened up this induction heater to find that it only has maybe 12 AWG wire in its work coil, rated for 30 A RMS. I've been doing induction heater simulations for a project, and the two topologies I'...
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### Equation relating alternating magnetic field strength to induced voltage in search coil

I have a search coil (loop area A, N turns) placed normal to an alternating magnetic field with equation B(t)=Bp.sin(2.pi.f.t), B=field strength at time t, Bp=peak field strength, f=frequency, t=time. ...
1 vote
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### How would you calculate induced voltage from a radiated electric field?

This may be somewhat of a classical question based upon Radiated susceptibility testing performed in avionics qualification testing; given a given electric field strength (V/m) at a given frequency, ...
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### Could actuator (DC motor) damage the relay that controls it?

I have a 12V 22A DC actuator that I turn on/off with an automotive 80A 12V relay. Could turning it on and off cause damage to relay in the long run? I understand a diode is required on relay's control ...
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### Heating and cooling a liquid in a test tube electronically

I am automating a small-scale laboratory chemical process. One step is thermal equilibration of DNA in about 0.5 ml of aqueous buffer, which involves raising the liquid to 90°C and then immediately ...
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### Will a nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI) impulse blind our signal response sensor?

After we send an impulse to the coil, when we start read the coil will have self oscillations. What influence will the self oscillations have on the read response? How can we deal with the self ...