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Questions tagged [ac]

This tag refers to alternating current mains power. It usually applies to voltages with >100V RMS, but can also be used for ex. 24V industrial AC power.

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2answers
59 views

Variable Frequency Drive with AC motor, 30kW

I have a VFD that controls an AC motor which compresses air. It is an 30kW motor. I have set the parameters required to drive the motor and it runs the motor but not properly. During the test the ...
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0answers
367 views

Use 230V 50Hz electronics in U.S.A [migrated]

I want to visit friends in U.S.A. and may stay there for maybe a month. I would like to bring my electronics with me and need to know how I could use them in America. They use 230 V, 50 Hz (I am from ...
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2answers
42 views

Do I need a fork terminal to install #8 into an 38660 Molex Barrier Strip?

Can I strip a half inch of wire from a #8 cable and screw directly into a 38660 Molex connector? Or do I need to buy a spade terminal. This is for an AC connection to the back of a DC power supply, ...
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2answers
55 views

Physical connection of AC and DC voltage sources in series

in many circuits (Amplifiers, Filters etc) at the input terminal I saw a sinusoidal voltage together with a DC term, i.e. a voltage like v(t) = sin(wt) + 1 [V]. We may imagine that this signal is ...
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0answers
45 views

Send an AC signal from a DC device

I was able to read a 18VAC signal from the old-school door bell with a voltage divider to my 3.3VDC ESP controller. Nice. Now, I wish to send a 18VAC signal (for 3 seconds) to open the door with that ...
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2answers
57 views

Phase difference between resistor and inductor voltage in an RL AC circuit

In my textbook, it is given that \$\mathcal {E} = -L\frac{\Delta I}{\Delta t}\$. The graph of resistor voltage (\$V_R\$) and inductor voltage (\$V_L\$) in a series RL AC circuit is given similar to ...
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0answers
55 views

Why should the primary winding of the transformer not be grounded?

I've been wondering what would happen if you grounded both star points of a Y/Y connected transformer. This shouldn't affect the voltages, so why really is it not advised to earth both the primary ...
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2answers
58 views

Light dimmer with capacitor [on hold]

I have a capacitor in series after a light dimmer. How could I calculate the voltage and current through the capacitor? simulate this circuit – Schematic created using CircuitLab
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3answers
97 views

Computing the voltage across a parallel LC component at resonance?

Problem For the circuit illustrated below, I am trying to compute the sinusoidal voltage across resistor \$R_{1}\$ when the parallel LC component is in resonance: I setup my problem with the ...
1
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1answer
22 views

Current flow in trailing edge dimmer

I was trying to learn something about dimmers for light bulbs. After some reading, I found that most trailing edge dimmers contain some variant of this: Found for example in this diy-project or this ...
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1answer
66 views

Is there any hope for this power supply to work on 220V rather than 110V? [closed]

I stupidly moved my laser printer with me overseas without checking whether it would take 220V. I assumed it would be like my desktop computer and accept both. Anyway, here I am with a 110V printer ...
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1answer
53 views

Best way to generate 26 Volts AC at 380-420Hz?

I have obtained a military vibrating-reed frequency meter that I would like to turn into an educational display unit, with a knob that adjusts the frequency from 380 to 420 Hertz, giving the user the ...
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0answers
58 views

How is AC load distributed across on-site generation and the utility?

I’m trying to understand the physics behind AC load distribution when distributed on-site generation is installed and the load is also connected to the grid. In the diagram below, I have a building ...
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0answers
19 views

meanwell psu inrush current and temperature sensor

I want to use a Meanwell PCB mounted power supply on my next project. https://www.meanwell.com/Upload/PDF/IRM-20/IRM-20-SPEC.PDF The spec sheet says that it has an inrush current of 20A/115VAC (I'm ...
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0answers
13 views

How can we simulate an AC position control system in simulink?

The final feedback loop which I got is the following How can I implement this using Simulink?
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1answer
20 views

Power Gain in a Small Signal Mosfet Circuit

let's consider this circuit, which is the equivalent of a small signal Mosfet amplifier. where RG is a gate series resistance which takes into account of the oxide leakage, and CGS and CGD are the ...
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0answers
50 views

how is this transformer working with DC? [duplicate]

As I was going through the SMPS circuits online I came across this circuit: I searched and learned that the transformer steps down or step up only AC power supplies and then converted to DC using ...
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1answer
34 views

Resistor power dissipation when driving optocoupler from ac mains

I followed this: https://learn.edwinrobotics.com/230v110v-ac-mains-detection-using-arduino-raspberry-pi-and-esp8266-thing/#Step2 With the exception that I used an LTV-814 that doesn't require a ...
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1answer
22 views

TUHS3F05 without other components

I'm planning to use TUHS3F05 for my ESP32 project. I'm very space limited so I need to optimize place as much as possible. In datasheet it is recommended that TUHS* it should be used with other ...
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46 views

VFD as general use inverter

I'd like to have 3ph 208 in my house for general use (not a motor). If I run the output of a single phase to 3 phase VFD through inductors or a 1:1 transformer will it smooth the SPWM .output into an ...
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2answers
57 views

Why is phase of current assumed to be 0 when deriving formula for instantaneous power in an AC circuit

In two different books I'm reading the authors start the discussion of instantaneous power delivered to a load in a steady state AC-circuit by assuming \$i(t) = I_0 \sin(\omega t + 0)\$ and \$u(t) = ...
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2answers
83 views

Confusing equivalent AC circuit (analysis)?

Context I'm doing some analysis on a dummy circuit. I've been explicitly told that the current generated by the source is a sinusoid: $$I_{0} = I_{p} cos(\omega t + \pi/2)$$. It also have been ...
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1answer
79 views

Will 2000A Inrush Current Damage Outlet Circuitry?

First time building an AC control system complete with motors, PLC, sensors, power supplies. All this is sourced from a 220VAC outlet. I have calculated the total current draw of all motors, powers ...
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0answers
33 views

I have a 2 phase ac motor I need to use as a constant speed brake, how do I modify my circuit to make this happen?

Please see the circuit below. I have a 2 phase AC motor 120v, 50hz, 250w, I need to use this to enforce a constant velocity against an accelerating force, or in other words the motor rotates ...
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1answer
29 views

connecting single phase motor to UK mains AC

I have a single phase single volt (UK 220-240) 1Hp electric motor with two capacitors, start and run. As photographed. This is to run my Milling machine. I need to connect the motor, via ...
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0answers
70 views

Apparent lack of rigor in Phasor domain analysis of steady state AC circuits

so I have encountered a hitch in my understanding of analyzing steady state AC circuits. I have looked everywhere for the answer to my question and I can find nothing. Usually when we analyze ss AC ...
1
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1answer
61 views

MCU conneected to AC Mains

I am developing a PCB which is having control MCU circuit, it will control the relays. Relays output are connected to 230V AC mains load (~100W load). This PCB is mounted on a cabin where people cant ...
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1answer
34 views

Switching 13.5VAC

Would a relay that's meant for mains AC work for 13.5VAC? If not, what type of component/circuit would be best suited for this application? This is meant for a door buzzer/opener that functions on 13....
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1answer
56 views

How can I Power a 20-50mA LED from the 240V AC Wires of a Motor in a Safe Way?

I own an ice cream machine which is perfect, except it lacks a light so one can check the state of the process. The motor case would be the perfect place to install a white LED, which will consume ...
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2answers
34 views

What terms to differentiate between a quasi-synchronous motor (eg an induction motor ) and a completely asynchronous motor (eg a universal motor)?

I am editing a table of motors. I am looking for the correct terms to distinguish two types of motors: motors whose speed is less than the AC frequency (all inductions / squirrel cage motors) from ...
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0answers
69 views

Does current in neutral wire flow like this? [duplicate]

I've read neutral wire in 1 phase AC at home has almost 0V at both ends. But still current flows through it. So I've assumed 0.1V potential at the other end near a resistance (bulb). Now there's a ...
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1answer
87 views

Why do we not get shocked by neutral wire and how can it behave as it does? [closed]

I read some articles and watched videos regarding 1 phase and 3 phase ac. And later found that for most home appliances we need 1 phase ac. Then I came to know about live and neutral wires. Few ...
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1answer
64 views

AC coupled sinewave

How can I see in this picture that the signals are AC coupled? Does not AC coupled means that the DC offset is 0 and the sine is centered to the origin? Both signals have an offset from what I can ...
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5answers
2k views

Does an oscilloscope subtract voltages as phasors?

I want to measure two voltages on an oscilloscope. They are not in phase. I want to know the magnitude of the voltage difference. The oscilloscope has an in-build math function to subtract the ...
1
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4answers
132 views

Safety: Can I harm myself using an AC, 9V 500mA power supply for experiments?

I'm about to embark on my first electronics project and would like to check off a safety question: I want to build a bicycle hub dynamo -> USB charger based on these instructions. It is basically a ...
9
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3answers
3k views

What is the name/purpose of this component?

I was wondering what is the role/purpose of the electric component in the red square. This is the schematic of a 230V single phase induction motor. What is also not clear to me are the connections on ...
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2answers
48 views

How to transform an AC signal of wide voltage to pulses

I want to build a device that measures frequency of possibly different electrical alternators, not having much control of their parameters. For this I need to get digital pulses out of the AC signal ...
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3answers
586 views

Why would an AC motor heavily shake when driven with certain frequencies?

I have an AC motor from an old TCL 160 Boxford NC Lathe, it has three wires named U V and W. I thought that incorparating the original driver to a modern control interface card would be difficult or ...
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3answers
60 views

120V between chassis grounds of two different devices [duplicate]

After experiencing a notable shocking type sensation after coming into skin contact with my laptop and phone (both metal and plugged into their chargers), I decided to probe the chassis of both ...
0
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1answer
26 views

Surge protector outlet with altered grounding potential

I realized that I have a voltage difference of 5 to 80 V AC (orange in Fig. 1) between the protective conductors (grounding cables, "PE-Leiter", yellow-green contacts in drawing) before vs. after a ...
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2answers
109 views

Why arc only happens when circuit on load?

I'm preparing research about high voltage electric distribution for my university but I don't understand why the arc only happen when current is flowing. I made my internship in an electric ...
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2answers
103 views

I'm trying to learn how to make these circuits but have no clue if I'm on the right track? [closed]

I've recently been doing some online tasks but I am really struggling to understand how build this circuit in multisim. I am also struggling to calculate the values listed in 2. and have tried to find ...
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0answers
41 views

AC capacitor current spike

I was experimenting with capacitor voltage divider circuits but something unusual happened. Circuit is really simple , I connected 100uF 16v capacitor into 13.85V 50hz AC supply Xc is 26.5 ohm So I ...
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3answers
115 views

Identifying function of passive components in op amp circuit

I was reading this report on a digital guitar effects pedal design and I came across the circuit above. "AUDIO_IN" is where the guitar signal enters the pedal. The signal is then filtered through the ...
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2answers
87 views

Unexplained amperage spikes

IT guy here - I have a device called a WattBox in one of my networks so I can remotely cycle power on an outlet. It also provides me with alerts when something falls outside set parameters. I've ...
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1answer
50 views

What AC mains phase information can be deduced from measuring at two distinct devices, connected via ethernet?

I a have a house with 3x20A grid connection. With the usual big loads like washing machines, kitchen. For each socket in the house (many...) I want to determine the phase a wall socket is connected to ...
1
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1answer
47 views

Finding a gain bandwidth product using a test frequency

For GBP datasheet parameters of Op-amps, I have seen datasheets with test conditions like gain and Rl, but there are also datasheets with ftest as their conditions. How do we calculate the GBP of the ...
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2answers
50 views

Help with my design: How can I add these voltages?

I have to design a circuit that simulates a voltage spike on a dc supply rail. The circuit has a button that, when pressed, generates a short pulse of controllable height (controlled by pot). The ...
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0answers
30 views

What's the proper way of mounting surge arresters on TN-S system?

I'm attaching a diagram with surge arresters put on each line. Most of the experts in the field say a proper defense against lightnings and switching events has three surge arresters - one between ...
0
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1answer
82 views

Heating vacuum tube filament via capacitor

As I understand vacuum tubes (like triode / pentode) usually are designed to be heated with certain current through the filament. And usually it is about low-voltage and comparatively high-current. E....