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Questions tagged [electrical-engineering]

Study and applications of electricity, electronics, and electromagnetism. Use this tag when someone who has trained as an electrical engineer is likely to be able to answer your question.

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What motors to use to guide tape with high speed

My field isn't dealing with motors and such at all, however, I now need to build something that controls two motors. So I have two guiding reels with tape between them, similar to old tape recorders. ...
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1answer
21 views

Sonomotors, Sion: Can this electric car really charge up to 30km only from its solar cells?

Maybe you have heard about Sonomotors and its futuristic electric car, the Sion. If not, here is the link to its website: https://sonomotors.com/ Anyway, the manufacturer claims that this car can ...
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17 views

Communications Question: Resource block parameters?

I am modelling a network using MILP/AMPL; in this network there are a multitude of UEs and 16 basestations (BS) (4 macro cells, 12 small cells). Each BS has resource blocks (RB) consisting of 12 ...
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PWM to analog RC based filter with minimum analog voltage level

Trying to design a circuit to accomplish the following: 5V PWM signal is converted to 0-2.5V analog voltage The analog voltage should never drop below a certain minimum voltage level, when PWM is 0 ...
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15 views

Example induction motor

I have three phase induction motor: $U=6\text{ kV}$ $P=630\text{ kW}$ $f_1=50\text{ Hz}$ speed of rotor $n=1410\text{ rpm}$ Maximum moment is reached when $n=1120\text{ rpm}$. Now voltage and ...
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25 views

What formula can be used to calculate the motion that will be created by unbalanced magnetic suspension?

I would like to know what formula can be used to calculate the distance that a maglev device will travel if it were to have unbalanced magnetic suspension. Please reference the drawing below. Say ...
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1answer
25 views

Voltage controlled switch?

So I am in the process of working on a rather strange and specific project. I am looking to capture as much energy as possible from a small steam turbine using a DC motor and then use that to power ...
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1answer
36 views

Choosing a proper BLDC motor for lab centrifuge

I'm trying to make a swing rotor centrifuge and find a proper BLDC motor to reach 6000G with capacity of 4x50ml Falcon tubes. I did the calculations roughly but I'm not so sure about them and also ...
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1answer
30 views

Build Device for Emitting Weak Air Bursts at Specified Frequency

I'm a neuroscientist interested in building a device to replicate the following study. https://www.nature.com/articles/s41598-018-24924-9 Essentially, they sent air through a nose catheter to ...
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1answer
23 views

Unbalance voltage mesurements from 63 kV power transformer

After testing a power transformer(pt) and closing its wiring terminals I've encountered that phase S 63 kV correct voltage and phases R and T shows incorrect voltage 32 kV. Can any body tell why?
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How to prototype this circuit using an Arduino and breadboard?

I'm trying to build this circuit for a force transducer such that the data is logged by an Arduino Uno. I have the op-amp recommended in the schematic, but I haven't been able to get stable readings ...
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21 views

detection and verification

we are building a smart cat door that will unlock automatically when ONLY our cat is close to it (within a range of 3 ft). we tried using RFID, however it has a limited range, which was less than 2 ...
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13 views

Help on solving and deriving equations for the Output Voltage on a Voltage Divider with a Load Resistance?

I'm having trouble understanding how to derive the equation to solve the output voltage for a voltage divider with a load resistance. One of the problems that I'm solving says that the equation is Vo ...
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1answer
43 views

What is the capacity of a WWII Submarine battery in kWh?

After reading about submarines in World War II, I was curious about their battery capacity, specifically in comparison to modern Battery Electric Vehicles (ie Tesla, Bolt, Leaf, i3, etc). I haven't ...
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14 views

Does the frequency of input voltage in induction motors have to be continuously altered?

I understand that for magnetic lines of the rotating magnetic field to cut the windings of the rotor (and induce current), the field has to rotate at a slightly higher rate than the rotor. But if we ...
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2answers
34 views

Why does aluminum clad steel wire have high corrosion resistance?

Why do aluminum clad steel wires have high corrosion resistance despite being two dissimilar metals? Does the aluminum act as a protective & sacrificial layer similar to zinc in galvanization or ...
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1answer
23 views

Satellite Thruters with reversers

Are there any satellite thrusters that mimic the "thrust reversal" feature of airplanes i.e. (A320...). I already know of procedures to decelerate a satellite such as using two separate thrusters ...
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How to identify trip coil circuits of Circuit Breaker?

Recently I've encountered Cercuit Breaker without any control circuit diagram. Just many teminals and wires without any tag! I want to do timing test of CB. How can I identify trip coil circuit?(Using ...
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9 views

Individually Addressable Motor Strip

Can you make an individually addressable motor strip if you replace led with motors?
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2answers
57 views

Activating lights using a motion sensor?

I was wondering how I would configure some sort of setup to get lights like this turn on a timer once activated by a motion sensor. I want them to turn on for about 15 seconds and then turn off once ...
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1answer
24 views

How much power will 4 germicidal lamps use?

I was wondering if this portable power supply will be sufficient for running 4 UVC lamps all at once. If so, for approximately how long? Power Supply: SUAOKI G100 27000mAh /3.7V Power Bank Station ...
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1answer
24 views

Camera and light frequency rate

I recently became curious why some lights flicker in some videos, and I read some explanation about it, and I still have some questions. 1. Does every light have to have a frequency? can it have an ...
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1answer
50 views

Why are phones not getting charged when I supply 5 V and 0.3 A?

I'm using thermoelectric module to get the voltage. With the help of it, I'm getting 3 volts Open circuit voltage. I've attached DC-DC converter which regulates this voltage to 5 volts. I've attached ...
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1answer
38 views

A board or mat that we can detect a push at an exact point

Is there any kind of board or mat that when we place it on the floor and wire it, a self-made connected device can read these data when it is being pushed and holding onto it, at multiple points? ...
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2answers
37 views

Maintain voltage and current supply to device in extreme cold

I am running a DSLR to take time lapse photos for long periods of time, often overnight, often in extreme cold (-20F). If at any point the camera does not get enough power, it shuts down - time lapse ...
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What is the difference between an Inside Noise and a Structural Noise in Audio Engineering ?

Structure-borne sound : This results from an impact on, or a vibration against, a part of a building fabric resulting in sound being radiated from an adjacent vibrating surface. knowing that a ...
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1answer
51 views

Torque and power for elevator with counterweight

I need help calculating required torque and power for an elevator to select appropriate motor and gearbox. The mass (weight of elevator plus max load) is 2000kg The speed of the elevator is 10 m/s. ...
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2answers
54 views

Why is the color gamut of an RGB monitor triangle-shaped?

Relative to the CIE chromaticity diagram, it is usually said that rgb monitors can't actually reproduce the entirety of colors in that diagram. The best they can do is cover a triangular region inside ...
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1answer
31 views

Difference between permanent magnet and electromagnet exciter generator in principles wise?

I searched about this, but couldn't find any helpful explanations. All it says is that magnetic field is generated by either permanent magnets or electromagnets. In both cases, how does the exciter ...
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1answer
35 views

What is tonal masking?

I have checked the definition of tonal masking on Wikipedia and google but I saw the definition of sound masking and auditory masking. Auditory masking Sound masking But I want to know what ...
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1answer
16 views

Get 2KV AC 15AMP draw from 2 lines of 220

How would I go by getting around 2KV ac rms able to support an average current of 15amp and max of 20amp out of 2 lines of 220? And what kind of relay could take that? Looking for a winding ratio.
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0answers
22 views

Force applied on board from bed of nails [closed]

For testing a new manufacturing process of PCBs in our company, we design 2 bed of nails. One bed will have about 80 nails while the other about 180. Both beds will use the same fixture that will ...
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0answers
20 views

Confused about information on a state transition table

I'm working with a State Transition table with a variable I can't identify. Here's the table: I'm pretty sure "a" is the present state. "b" is the next state and Sx and Sx+ are the inputs. ...
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1answer
43 views

Thevenin equivalent impedance in laplace domain

I can't understand why $Z_{th}$ doesn't include $3\ \Omega$ resistance.
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1answer
28 views

What is the purpose of the isolated subpanel terminal of a solar inverter?

In a grid-connected (utility-interactive) battery-based PV system, what is the purpose of the 'Isolated Subpanel' terminal of the inverter? EDIT: Found this descriptive image and hence answered the ...
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1answer
64 views

Is there such thing as supreme board for international arbitrators?

My cousin is a mechanical engineer, got contacted today from someone who claimed to be working for the supreme board for international arbitrators (sbia) and ICAC in the Middle East and north Africa ...
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0answers
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Where can I find an Electrical Engineering master or phd student for my GPR radar project [closed]

I want to make this project but lacking manpower and knowledge. I want to include one having knowledge and excitement. Where should I find one? I am just graduated. So no money I can offer. I can ...
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1answer
46 views

Tethered Balloons vs Towers for Wireless Communication

If we use tethered balloons (aerostats) with wireless gateways fitted on them (let's say for Cellular or LPWAN communication), they can provide much more coverage owing to the height they can reach (e....
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0answers
37 views

Simulating a mass - spring - damper system

I have a mass - spring - damper system with external force and I am trying to simulate it using Matlab. I want to have a linearly parameterized form and use the least squares method to find the ...
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2answers
91 views

The concept of flux

I find it difficult to understand the concept of flux and field.I have searched the internet and refered a few books.From what I understand, generally flux can be defined as "some quantity per unit of ...
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1answer
41 views

Question about converting 220V lamp to 110V

I have an old classic lamp (Tolomeo). It was purchased when we lived in Singapore, so it is designed for 220V. Since we moved to US, I have not been able to use it as the power supply here is 110V. ...
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1answer
670 views

Inverter + Direct drive vs. Belt drive motor in washing machines?

What should I choose from today. I am looking at washing machines, and I see that LG has this Inverter Direct Drive (6 motion cleaning) technology in their machines, I see that its not like a year ...
3
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1answer
66 views

What criteria to focus on when selecting a BLE module?

I am trying to select a BLE module for low power application. I have looked into different BLE modules from different chip manufacturers. For example: ISM78G1D Bluetooth Low Energy SIP from Inventek ...
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2answers
36 views

Can an AC rated temperture switch be used in a DC control circuit?

Looking to add a "high oil temp" warning on a machine tool by adding a temperature switch into the hydraulic circuit, right after the radiator before returning to tank. I know monitoring from the tank ...
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0answers
43 views

What are the strengths and limitations of the antenna design of the Montjuïc Communications Tower?

The Montjuïc antenna is an interesting design for an antenna. I presume the design is principally an antenna, but perhaps it is not? If the ring + mast is an antenna, how does the ring work to ...
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1answer
30 views

Why is it difficult to manufacture capacitors in femtoFarad or lower range?

Capacitors available in the market have a lower bound around 1 pF or 0.1 pF. Why is it difficult to manufacture capacitors in femtoFarad or lower range?
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1answer
50 views

LC oscillator circuit

Consider the following circuit: Let both capacitors be charged to equal voltage. The circuit acts as LC oscillator circuit with resonance at $f= \frac{1}{2\pi\sqrt(LC)}$, where C is the resultant ...
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0answers
32 views

High Pass Filter Design from Transfer Function

I need to design an active high pass filter circuit that implements the following transfer function: $$G(s)= 4.15\times\dfrac{s+530}{s+2200}$$ where, $K = 4.15$, Pole @ 2200 rad/s and Zero @ 530 rad/...
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1answer
118 views

How can I use a 5V pwm with a 12V pwm

I'm trying to control my 12V fan with a 5V fan controller. With this circuit the fan run at full speed. When I measure the voltage on PWM and ground I obtain 5V. Which circuit can I use to adapt the ...
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2answers
44 views

Why is the Current to Motor less than Motor Rated Current?

I have a motor for a submersible pump with a Rated Current of 8.4A as given in the motor's electrical data. However, when it is running, I record a current of 3.4-3.9A. Is there a fault I am supposed ...