All Questions
42 questions
0
votes
1
answer
39
views
Using MOSFETs to control series-wound flipper coil
I'm trying to control a series-wound pinball flipper coil using two N-Channel MOSFETs, like this:
The switches are mechanical leaf switches. The diode D1 is part of the coil assembly, I don't know ...
- 101
0
votes
0
answers
122
views
Taking into consideration the information provided, would the motor output the intended power?
Well, I'm not an electrical engineer and I'm trying to design a direct drive axial flux brushless torque motor with 300 kW with little weight as possible.
I'm never going to actually build it because ...
- 122
0
votes
4
answers
146
views
I have a solenoid rated at 24 volts AC, but at a trickle voltage of 1-9 volts the solenoid stays pulled in when it shouldn't be
I have a solenoid that pulls in at 24-30 volts ac to control water flow. It opens at 24 volts ac, but stays pulled in at a trickle voltage of .75 -1.0 volts. How can I stop this from happening?
0
votes
1
answer
177
views
Is this (working) 2-doorbell system dangerous?
In a previous setup, I had two doorbells, each one with its own 10V AC transformer, as detailed in Why is it impossible to connect these two doorbells in series or parallel?.
I now know it was ...
- 2,208
7
votes
3
answers
2k
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Why is it impossible to connect these two doorbells in series or parallel?
I have:
one 220 V AC -> 10 V AC transformer
one push-button switch (at the door)
two bells for two different places of the house; they should ring together when the (single) door push-button ...
- 2,208
0
votes
1
answer
157
views
Thyristor external power supply
I am trying to make a kicker solenoid. My circuit is:
12 V battery connect to DC step up booster 300 V
diode
thyristor BTW69-1200 with external circuit (battery 1.5 V - resistor 1/4 W, 39 Ω)
...
- 465
4
votes
2
answers
271
views
Switching kicker solenoid with an idea out of the box
From my previous posting some may know I am planning to make a kicker solenoid.
The circuit specs:
Coil - 3.5 Ω, 3.4 mH (inductance)
Capacitor 1000 μF, 450 V
DC booster up to 410 V
12 V DC battery
...
- 465
0
votes
1
answer
58
views
Relay rating for 390 V solenoid
I saw a video using car relay 12V/40A for a solenoid using 390 VDC and about 80A.
https://youtu.be/fVGrYoqn-EU
https://youtu.be/GsnxzMAczHU
I know relay can suppress the back-EMF from coil.
I want to ...
- 465
0
votes
3
answers
181
views
Calculating current a capacitor can deliver
I made a simple coilgun circuit
Capacitor 50 V 10000 uF
DC power supply of 20 V - 5 A
Coil of enamelled wire 18 AWG - 3.5 ohm
My calculations according to Ohm's law the current in the capacitor ...
- 465
6
votes
1
answer
1k
views
Measure inductance of air core inductor
I am making an inductor
Air core
Wire: 18 AWG guage
Turns: (I am not sure ) but could be about 6000 turns
The weight of the wire : 400 gram
The coil wrapped by machine
Coil is 5 cm
Diameter of core ...
- 465
3
votes
1
answer
2k
views
Calculate the number of turns in air core inductor
Coil specification:
Air core coil
Length 790 mm
Diameter 290 mm
Wire guage 18 - 1 mm diameter
I need the number of turns to get an inductance of 150 mH.
While searching for calculating the number of ...
- 465
1
vote
4
answers
3k
views
Designing an RC snubber for AC solenoid lock (inductive load)
I am designing an AC solenoid lock. Here is my design:
Resistance 8 Ω
Main outlet power source 220 V - 50 Hz
Inductance 150 mH
Impedance 47 Ω
I (RMS) ~ 5 A
I read that the inductive load needs a ...
- 69
1
vote
1
answer
248
views
Designing AC kick solenoid lock
I am making a kick solenoid lock with AC.
I designed the circuit to run on 220 V, 50 Hz (household plug.)
The inductor (coil) is air core
500 turns, 150 meter (500 ft) in length with inductive ...
- 69
1
vote
2
answers
328
views
How to make a 220 V AC solenoid lock
I need to make a powerful solenoid lock using 220 V AC.
Let say I will use 21 gauge wire and get a length of 24 Ω. This will draw 9 A from the 220 V, so 1980 W.
This will be great force ...
- 465
2
votes
3
answers
710
views
Turns in solenoid coil or coilgun
more turns = increase in wire length = increase in resistance = decrease in current
So how come more coil turns will increase the strength of electromagnetic field?
- 69
0
votes
1
answer
182
views
Can I use AC voltage for a solenoid lock?
I want to make a very high force solenoid lock. I want to use AC over DC because the most voltage I can get from DC is 12 V (I don't have a power source supply more than 12 V).
So can I use AC to make ...
- 69
0
votes
1
answer
754
views
How does a camera flash get high voltage and current from a small battery?
I am a beginner trying to make coilgun. I see videos use camera flash circuit with capacitor that outputs 220V and a good current (5A) from 1.5V AAA battery
How does this circuit work to give this ...
1
vote
3
answers
2k
views
Amp and voltage effect on solenoid coil
If I have battery of 7.4 V and 10 A = 74 watt connect to solenoid coil.
And if I have battery of 12 and 6 A = 72 watt (almost 74) connect to solenoid coil.
And they are under same situation (same ohm, ...
- 465
1
vote
1
answer
100
views
Switching transistor for micro solenoid
You may have seen some previous posts of mine asking various questions about frequency dividers. I have a circuit I think I am happy with for producing at 1Hz 12.5-25% duty cycle.
I now would like to ...
- 135
0
votes
1
answer
160
views
Finding out the magnetic field inside the cross section of the torus which is wrapped by conductive wire and the current flows it
As shown in the diagram , the torus of radius of \$~ R ~\$ exists .
The wire is wrapped around the torus .
$$ N:=\text{total number of the turns of the wire around the torus } $$
The current is ...
0
votes
1
answer
73
views
\$\delta n \cdot x + n \cdot \delta x~\$ equation of shrunk coil with incremented number of turns per unit length
The very long coil exists with the following information .
$$ a:=\text{radius of the circle of the coil} $$
$$ n:=\text{number of turns of the coil per unit length} $$
$$ x:=\text{length of the ...
4
votes
5
answers
5k
views
How to optimise wire gauge selection for electromagnetic applications?
Disclaimer: Hobbyist "maker" with limited experience and no relevant education. Please considerate and answer in detail. Feel free to skip to "Question".
Context
I have an ...
- 143
1
vote
1
answer
425
views
What equation should I use to calculate inductance of wire coil?
I've been working on a project recently which requires me to build an inductor, however in my research I found many different equations (with a range of variables used and giving very different ...
1
vote
1
answer
139
views
Degradation of resonant sine wave signal in coil/solenoid after adding second layer
I have hand-wrapped a couple of air core tube coils/solenoids with 50 gauge wire (0.001 inch diameter). My goal is to obtain a resonant frequency of ~10 khz without the use of a capacitor and to keep ...
1
vote
1
answer
172
views
What kind of motor is this? Looks more like a solenoid than a motor
I was going through a large box of random motors I got at a yard sale. I was sorting them for use in later projects when I came across a motor I couldn't classify. Long story short, the magic smoke ...
- 11
0
votes
0
answers
217
views
How to create optimal solenoid actuator
I would like to create a solenoid like this one:
It should be powered by 5V and of course I want it to take as little current as possible. I know it will probably still take a current of around 0.75, ...
- 137
0
votes
0
answers
92
views
How does Solenoid works? How do I calculate its output power? [duplicate]
Here is a solenoid valve. It is a normally closed, which is mean, it is normally closed the valve. Vice versa, there is also normally open, which is mean, it is normally open the valve until it ...
- 291
1
vote
2
answers
1k
views
How can we calculate the force of attraction between a coil and a ferromagnetic object?
As the question states I’m trying to figure out how I can calculate the force of attraction between the magnetic field of a solenoid (coil) and a ferromagnetic object. I suppose we should somehow ...
user234225
2
votes
3
answers
3k
views
How does one position control a voice coil actuator?
I am looking at trying to position control a voice coil actuator (something like these). On the end of the voice coil actuator will be a small load (let's just imagine a 10 oz cube), screwed onto the ...
1
vote
0
answers
210
views
Control a solenoid position "in / out" with power only (no spring)
I'm going to use a < 5$ solenoid (vertically oriented) that has to press something.
If I understand well, a linear solenoid like this one:
moves to one precise position when powered, but when you ...
- 2,208
0
votes
2
answers
64
views
Alimented coil close to a passive coil
If I build a coil A, of 10cm height with iron core and a 4cm diameter, and alimented it with a DC 15v,6amp source, it will produce a magnetic field.
Let’s say A is set vertically.
Will building ...
- 13
2
votes
3
answers
1k
views
Solenoid's field intensity calculation dependency on width/diameter of coil?
Textbook formula for field intensity in solenoid coil is
H = (N * I) / l
H magnetic field intensity in ampere-turns
NI ampere-turns
l is length between the coil ...
- 364
1
vote
1
answer
344
views
Designing custom solenoid with feedback for measuring force
I am contemplating the construction of a very small tensile force sensor based on the following principle:
1) Use positional feedback to a linear solenoid to maintain a fixed position when the plunger ...
- 213
0
votes
1
answer
107
views
measure temperature in a solenoid without sensot
is possible to meassure the temperature change in solenoid , without using a sensor?
I know the resistance will change with temperature, but are other parameters affected also ? will my current ...
0
votes
1
answer
621
views
Would a multi-stage linear solenoid work?
A common issue with small linear solenoids is that the stroke length is rather short. I'm pretty sure that increasing the stroke length would require increasing the strength of the magnetic field ...
- 155
1
vote
1
answer
600
views
How to calculate the induced voltage of two electrically isolated coils (solenoids)?
Suppose I have the following setup:
suppose then that:
Self inductances L1,L2, the radius R, the number of windings (turns) N1, N2 are all given.
V1 is given.
The distance between the coils (...
- 1,090
1
vote
3
answers
179
views
Is it possible to use a coil to create sustained displacement/preasure? without a permanent magnet?
So, as far as I understand, speakers are basically coils coupled with permanent magnets, then when a current is run through the coil it creates a magnetic field, pushing out against the permanent ...
- 291
1
vote
1
answer
2k
views
Need help trying to design an H-Bridge to power electromagnet
I am trying to design an H-bridge inverter to supply maximum current to my coils. I need to supply as much current as possible so that I can make a electromagnet whose polarity constantly flips so ...
- 25
1
vote
2
answers
2k
views
Parallel windings on a solenoid coil
Suppose I have a fixed voltage supply of 10 V and I need to get 20 amp-turns from my solenoid coil but my solenoid coil with 10 turns is 10 ohms, so I am getting 10V/10 ohms = 1A, 1A * 10 turns = 10 ...
- 35
1
vote
1
answer
300
views
What is the optimal disposition of coil to maximize the magnetic field created?
I am trying to create a powerful magnetic field using coil, and possibly some ferromagnetic metal bars.
The white box with the X on it, is empty, or made of air.
Saying that I have no limits on ...
- 125
1
vote
2
answers
137
views
Inductor Reactance
I have a few questions about the reactance of inductors at certain frequencies.
I have been working on a project that involves flipping the field in a solenoid with an air core at ~10-20 kHz with a ...
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15
votes
4
answers
61k
views
How to properly wind coils for a solenoid?
I need to wind a small electromagnet "solenoid?". About 3cm high and 2~5cm wide running at 5V/0.5A. This magnet will be put into a desk bell so it pulls the clapper down and rings the bell. I have ...
- 2,144