Questions tagged [electrical]

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Is it really sane to drop buckets of water into a (CRT) TV on fire after unplugging it?

Today, I read this absurd (to me) claim on what to do if your TV catches fire: Collect water and fill the unplugged TV. You can fill in only from the side. This is a necessary security measure. The ...
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1 answer
44 views

Why do inorganic LEDs wear out?

Why do inorganic LED bulbs have a limited lifespan? For example, a manufacturer may quote that a bulb or monitor powered by an organic light emitting diode(s) has a lifespan of 50,000 hours, while it ...
0 votes
1 answer
33 views

mg996r - maximum weight for robot arm

I want to build a robot arm (see https://youtu.be/F0ZvF-FbCr0) to move a dumbbell of 2 kg (roughly 2.2 lbs). However, since I have no background in engineering, I have no idea how to calculate / find ...
-1 votes
3 answers
56 views

Modifying bike wiring harness to add hazard lights

I'm trying to modify my bike's harness. Only trafficator functionality is supported by means of SPDT switch. I tried to add blinker functionality: Kindly excuse the symbols for both Relay and Switch. ...
0 votes
2 answers
55 views

Force required for a power generator in a coal power station

I am unsure about how to word this question properly and I assume that it might take two directions probably because of the unknown variables involved but here goes... On the actual physical power ...
1 vote
0 answers
48 views

Why does an electric motor, of 800 kW at 400 V, have 7 connectors for power cables?

I found a Vybo electric motor and noticed that it has seven connectors for power cables. I also found a Variable Speed Drive, Altivar Process ATV900, System ATV960, 800/630 kW, 400 V and its datasheet ...
1 vote
0 answers
29 views

What should be the clearance and creepage for the line to line 440 Vac and line to neutral 240 Vac of the three-phase system on PCB?

Also is there any link to calculate this as per the UL and other industrial standards
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2 votes
1 answer
68 views

Why did the metal railings to the stairs in the big ferries used to shock me?

When I was a kid, and even in adult age, I sometimes went on these large (well, to me, at least) cruise ships which had multiple (like ten) levels to roam around in. You either got there with the ...
1 vote
1 answer
50 views

Why do identical-looking power plugs randomly not fit in some sockets in the same power strip?

This has bothered me for many years, but I'm only now coming around to ask about it. I don't know if this is unique to Sweden or something, but for whatever reason, when I try to plug things into the ...
0 votes
0 answers
35 views

Electric Standing Desk

So, I'm trying to build an electric standing desk for myself. I drew what I have in mind as a guideline for my questions here. Basically I want a desk that varies in height from 65 to 130. I imagined (...
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0 answers
28 views

Differences between satellite dishes and Hertzian antennas

I have a text of notes for the electronics and telecommunication course, there is a section that talks about both the parabolic reflector antennas and the Hertzian antennas, in a test a question asked ...
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0 answers
35 views

How to control speed of DC Gearmotor with Varying Torque

I have a system where the torque is constantly changing, but I need the speed to remain at 9RPM. I have enough room for error where I can be between 8 and 10RPM. How can I achieve this? All I can find ...
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0 answers
42 views

Can a grid connected PV system deliver power backwards through the distribution transformer?

If there is no local load demand can a residential roof top grid connected PV system deliver power across distribution transformer [up to the higher voltage grid]? Suppose my grid connected solar pv ...
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1 answer
23 views

how would I identify when and who enter through a doorway, assuming they can have part of the technology on their person

I am working on setting up a system that senses when an object goes though a door. I've seen things using lasers or induction. I have a set of objects smaller than 1 square inch. I just want to know ...
1 vote
1 answer
36 views

Flood light pole components

I saw this flood light pole. It has two LED bulbs, but I do not know what the box in the middle is (it was not an LED), could you guys help me understand what this could be? This flood light is ...
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1 vote
2 answers
51 views

Connection to periodically electrify equipment

I am designing a system where I have a set of 4 electrical components rotating in a circle. In the bottom stage, the electrical component is submerged in water. In the top stage, the electrical ...
0 votes
0 answers
14 views

What conditions to properly measure surface resistivity using surface resistance meter?

I have some JEDEC trays that I need to measure it's surface resistivity. I have a surface resistivity meter to measure it, but I do not know what environmental conditions it is supposed to be measured ...
0 votes
1 answer
149 views

Can a battery-powered electric vehicle be driven through a dust storm?

I would like to know if a battery-powered electric vehicle such as a Tesla Model 3 automobile can be driven through a dust storm. Back during the Dust Bowl days of the 1930s, driving through a dust ...
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0 answers
25 views

Generation of Electrostatic induction

I need to generate a 500 volt electrostatic charge. How can I do this? I don't have a Van de Graaff generator. What are some practical suggestions? Basically I want to do experiment in which I need to ...
0 votes
0 answers
67 views

Are all boost converters isolated?

I have a few boost converters(3-6V to 40,000V) and I want to connect them serially. link In order for them to be connected, they have to be isolated. Is there any way to check that? If they aren't ...
0 votes
1 answer
42 views

Power systems unclear voltages

I was looking at this problem: "A balanced delta connected impedance load with (12+j9)Ω per phase is supplied by a balanced three-phase 60 Hz, 208-V source " I do not wish to ask for help at ...
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2 votes
3 answers
83 views

Eliminate cat ear and nose shocks during the dry season

My cat, George Valentine, really enjoys being pet. However, when the air here in Canada gets very dry (mid-fall), this activity creates static charges. Once the petting starts giving him relentless ...
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0 votes
3 answers
124 views

Magnetising a needle with static electricity using silk cloth

A nautical navigation textbook on my table says that we can magnetise a non-magnetised needle by rubbing it with a silk cloth. I decided to cross check on the internet, and found some experts calling ...
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0 votes
1 answer
47 views

How to find the torque required to rotate wooden slab

How can I find the Torque needed to rotate a wooden slab with no weight applied on either end of the slab if I have a servo motor placed at the middle of the slab?
0 votes
0 answers
69 views

Is there a way to output a variable from matlab simulink function block and use it to specify other parameters?

This function block outputs 'phase' which I then want to use as a variable like this: But as you can see simulink throws an error. I tried using Simout but it doesn't work. I am sure I am missing ...
1 vote
2 answers
69 views

Do piezoelectric materials produce a current flow or just an electric field?

I was watching a video https://www.youtube.com/watch?v=uvT3XvDSSQw about piezoelectric materials. They mentioned that "a current can flow when a pressure is applied to the material". I have ...
0 votes
0 answers
53 views

A regenerative braking system, what am I doing wrong?

I am currently working on a system of regen braking using two DC motors one of them is driven by the motor controller and the other one is using the main motor to spin in cases of full load and in ...
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1 vote
2 answers
43 views

Precisely control voltage output

I think the component name is a rheostat- is that what allows you to control the voltage output please? I want to control it in steps close enough to 0.1 ish volts? So I would like to attach a knob ...
0 votes
3 answers
61 views

Why materials with preferably a negative temperature coefficient for heating elements?

As far as I understood heating elements make use out of Joule heating. Hence, I wonder why one would preferably use materials with a negative temperature coefficient, therefore? Isn't it, that, the ...
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3 answers
68 views

AC/DC Laptop adapter power losses

I have a laptop power adapter shown in the picture below. It is written there 170Watt INPUT: 100-240V ~ 2.5A OUTPUT: 20V 8.5A I believe for AC Input they mean Root mean square voltage/current. for ...
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1 vote
0 answers
36 views

Homogeneous magnetic field inside aperture of PCB

I need to create a homogeneous magnetic field of a certain strength across a 10mm diameter opening of a PCB by using a current track on said PCB around the opening. The signal sent through the ...
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1 vote
2 answers
104 views

How to manage real-world too-long data cables?

Answers to a recent question about a homemade USB cable mention that USB and other data (Thunderbolt, VGA, and HDMI) cables should not be coiled. So what is the proper method to manage long cables ...
10 votes
4 answers
4k views

Extending USB cable makes it not work

I have a camera that uses a USB cable to connect to my computer. I want to extend the cable from 3ft to about 6ft. Originally I just created my own cable, soldering 4 26AWG wires to a blank USB ...
2 votes
4 answers
100 views

Inverting motor polarities automatically to close and open a door

Hi, I need to build a device that opens a chicken coop door. The idea is quite simple, a motor connected to an axle that pulls a string up just like a wench. It would be activated by a relay timer ...
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1 vote
0 answers
88 views

Equivalent Resistance Between Two Points in a Wye Network

I am interested in learning how to calculate the equivalent resistance between two points in a wye circuit for application to thermal networks (i.e. I'd like to calculate the equivalent thermal ...
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1 vote
1 answer
56 views

What is the difference between the power lines, USB lines, Signal, and PWM lines in a slip ring?

I'm currently sourcing a slip ring for a robotics gimbal I'm working on, and I'm not too sure how to properly source one. Currently, I need a slip ring capable of transmitting USB 3.0 data alongside ...
3 votes
1 answer
96 views

Electrostatic grounding of an electrically isolated concrete floor

I have a question regarding a not-so-common construction setup for a house. In this situation, the concrete slab is "floating"/insulated with a rigid insulation underneath. I understand the ...
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1 vote
2 answers
76 views

How to drive variable power (up to 1500w) to a grill heating element [closed]

I have a heating element like the following: which is rated to 1500W. I need to be able to drive up to 1500W of power to it, but potentially less. I will be plugging it into a 120V wall outlet. I am ...
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1 vote
1 answer
71 views

Do DC generators require more maintenance than AC generators?

Whilst researching, I found several sites that suggested DC generators required much more maintenance than AC generators. From what I can tell these sites seem to have assumed that the AC generator ...
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3 votes
1 answer
172 views

Does electricity go through non-metal materials or not?

Ever since I was a little boy, I've always had this idea that electricity can only go through metal materials. For example, if I put a 100% metal screwdriver into the socket in the wall, I'm going to ...
0 votes
1 answer
80 views

Peltier module set up isn't cooling

I have set up a Peltier module with an aluminium heat sink, cooling fan, 12V, 7Ah battery supply and thermal paste for the purpose of cooling water. At first, it performed well. It dropped down to 3.5°...
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0 votes
2 answers
128 views

Solder joints advice

Do you think these power distribution joints would suffice or should I improve on them?
0 votes
1 answer
54 views

Back EMF from a motor

I have a large DC Motor I ripped out of a treadmill and I'm curious if the back emf generated from manually rotating the motor is a DC output or an AC output. Is it AC only when it's from the power ...
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2 votes
0 answers
46 views

Transferring the project from "Altium Design" to "SolidWorks" while maintaining silk-screen printing, sizes and everything else

I want to transfer the PCB project to solidwork from altium design, I read forums on how to do it better, and so: Save to STEP. The option is good and working, but I did not like the option, since ...
2 votes
1 answer
299 views

Raspberry pi, Stepper Motor and level shifter

It is my understanding that a Rasperry Pi cant handle 5V on the GND-pin. For that reason I got myself a level-shifter which is supposed to be able to change the output from 3.3V to 5V. I need it to be ...
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1 vote
0 answers
141 views

VFD or soft start to minimize power consumption on starting a motor?

I want to use the smallest generator possible to run a standard three-phase AC well pump. According to this website and others, it is advisable to use a generator capable of 3x the running kVA if the ...
0 votes
0 answers
30 views

Convert values of utilization category from AC7a / AC7b to AC5a / AC5b - Is it possible to estimate?

I have a contactor which is rated at 440V and 25 A for utilization category AC7a and 8.5 A for AC7b. Is it possible to give an estimate about the maximum current and power usage for appliances of ...
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RLC circuit problem

After the switch is open for a long time, it is closed at t = 0. How can I find iL(t) and Vc(t) for t>=0? I tried step response for RLC circuit but I could not apply.
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-1 votes
1 answer
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How can I create an RL circuit?

I want to create a RL circuit that has a dc voltage source, lamp, switch, R and L elements are connected in series. How can I design the circuit so that the lamp flashes from the moment the switch is ...
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0 votes
1 answer
96 views

Motor sizing for modelling

Im working on a headrest for a car that will electrically adjust up and down and have drawn up my plans. it now comes to the important questions, such as what motor to use. Ive been looking at motor ...