All Questions
Tagged with transformer ac
274 questions
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Driving a transformer with an AC to AC converter
I have a variable inductor which operates at a 60Hz frequency this goes to a control board that takes this variable voltage and applies it to a high voltage transformer. I want to control the output ...
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2
votes
1
answer
228
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Transformer power mismatch in Falstad Circuit Simulator, bug or true to life?
To understand how transformers function better, I created a circuit in Falstad Circuit Simulator. As you can see since the transformer has equal amount of coil windings in both sides, the current and ...
5
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2
answers
686
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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 ...
- 151
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1
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57
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AC Stepdown transformer blown troubleshoot
I've had a ring doorbell pro for about 5 years, it's wired directly to the following transformer output 1 & 4 (24v):
It's using the original doorbell wiring, which rightly or wrongly, was wired ...
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3
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876
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Transformer with same size symbol meaning
I Know these symbols mean a transformer step up or down:
But what does this one represent since it has the same size on both sides?
Part above taken from this schematic:
And this also has me ...
- 805
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2
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121
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Understanding Current Ratings in Step-Up Transformers
A step up transformer increases voltage while decreasing current because we can't get more energy than what we had in the first place.
The thing struggles my mind is how his power has a current rating?...
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2
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57
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Dealing with High Voltage Low Current Transformer Inrush and bypassing a Thermistor
As a learning project, I am designing a power supply section of a guitar amplifier that uses a 120V Primary, 250V 45mA 40VA Secondary Transformer. Without any thermistor in-line on the main supply, I'...
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2
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2
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356
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Power transformer design calculations
I´m currently designing power transformers in a pretty basic way, using AWG tables for the section of the copper wire, and not knowing what are the real losses, just overdesigning.
Three phase ...
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3
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288
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Need to make 380V and 415V 3-phase motors work with 480V 3-phase power supply. Will a 480V->400V autotransformer cut it?
I will have multiple 415V and 380V motors to power with a 480V/3-phase supply due to an international supply chain and tight budget. I would like to know if the solution to my issue is as simple as ...
- 417
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4
answers
244
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Voltage difference between input and output of transformer [closed]
I have been trying to find the voltage difference between the input and output terminals of transformers, but every google result just got to the primary vs secondary so I decided I would just ask ...
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1
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278
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Does transformer efficiency affect output voltage or current?
I have a list of basic problems. Let's suppose a textbook problem. A transformer has an efficiency of 93%.
We know the primary voltage and current. We know the numbers of turns and the efficiency.
The ...
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1
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48
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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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1
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4
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314
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Is it OK to use a transformer as an AC power supply source?
I work as an IT specialist in company. The company acquired a used Axis 232D+ surveillance camera.
This camera is special. It requires a 24V AC 1.5A power source (as specified on p.48 here.) It was ...
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2
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2
answers
94
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What is the best way to convert 3ph 380VAC to 3ph 0V >> 450VAC in range of 800 kW?
I have a company that makes servo AC voltage regulators and some other transformer-based products, and today some of my customers asked me to give him a quotation for an 800 kW Variac, the biggest one ...
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1
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103
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Stepping down a toroidal transformer from 35v AC dual to 24v AC single power supply
I want to use a toroidal transformer dual 35.5v AC currently inside an old power amp as an external power supply 24v AC single. There are no details on the trans but I include a pic and the voltage ...
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1
answer
107
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Current in secondary side of step-down welding transformer
I am confused about the use of a step-down transformer in a welding machine. The transformer steps down the voltage, let's say from 220V on the primary to 12V on the secondary. It is said that it ...
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How to add LED array to 110VAC AC circuit that includes small motor
I'm building a small machine that uses 110 VAC to power a small (14 W) motor. I want to add an LED array that a switch activated by the motor turns on and off. (The motor will also be gearing some ...
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1
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1
answer
90
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Do Kirlian setups work with DC power? [closed]
I have been trying to build a simple Kirlian setup, and I've been trying to make my flyback transformer work, to no avail, so I shifted to use the small black 3.7 V to 400 kV transformers (as they ...
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183
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Electronically controlled variable AC-AC and DC-AC
I've seen devices (and saw answered questions) that are somewhat similar to what I want to do but I haven't found exactly what I'm looking for. I want to control a power supply with my Raspberry Pi ...
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0
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50
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How can I electronically measure the load of an AC transformer?
I'm wondering how to electronically measure the load of an AC transformer at the output of the secondary winding. I don't want to calculate the core size but use a measurement instrument - which one? ...
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1
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I need to replace an old Basler AC Transformer. I can't find a replacement. How do I determine what to replace it with?
It came out of Payne Central AC PA10JA042000ADAA. I tried emailing Basler - no response. Any help would be appreciated. I don't want to replace the whole AC unit for a bad part. Some numbers from ...
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2
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2
answers
454
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Transformer that doesn't take power when not used
With Is this (working) 2-doorbell system dangerous? and Why is it impossible to connect these two doorbells in series or parallel?, I arrived to the conclusion I need a new 220 V AC => 10 V AC ...
- 2,198
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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 ...
- 2,198
2
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4
answers
1k
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How can you use a transformer with an AC current?
I see transformers being used quite commonly for AC power and in many places I see people saying that they are meant to be used for AC. The way I understand it, transformers use large inductors around ...
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2
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88
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What is the term for variable auto transformers that are computer controlled?
I want to test when some devices consider a voltage to be unfit, so I need to sweep a rather wide range of AC voltages to determine the tripping point. Currently, we have an employee twist the knob of ...
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2
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1
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120
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Transformer changing voltages at input
I have a confusion regarding the input voltage of the transformer. Is it necessary that the input voltage of the transformer should change its direction. If I give an input voltage, a sine wave but no ...
user340506
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2
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146
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Transformer design problem
I will try my best because my English is not the best. Thanks!
I'm designing a transformer for a PCB that I made. The circuit in the PCB accepts 5 V to 20 V in.
So the transformer that I made is for ...
- 155
0
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1
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115
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AC step down circuit
I have a quick question about a circuit I want to build, namely a low voltage AC power source.
I attached a picture of the schematic.
Are there any safety concerns that I might have to pay attention ...
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1
answer
1k
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How to wire a 480 V AC to 380 V AC transformer?
I have to install a reflow oven which needs 3-phase 380 V AC to power on.
There is a transformer (as the picture shows) that came with the oven. I assume that the black wire is the "hot" ...
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91
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Finding power factor of primary windings of a transformer
A transformer rated at 250kVA with nominal voltage 20/0.4kV outputs 400V to a load with a power factor of 0.8.If the resistance of the primary windings is 15Ω , the reactance of the primary windings ...
user334808
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1
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330
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Why is the power factor neglected in the transformer equation?
The transformer equation is VpIp = VsIs (p is primary and s is secondary). Why is it not VsIscos(φ1) = VpIpcos(φ2)?
Why do we neglect the power factor in both cases, is it equal to 1? I know input ...
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2
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4k
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I have 208 V, three-phase. How do I get single-phase 208 V or 240 V?
If 208 V three phase is constructed of three 120 V lines, what is the most simple and safe way to get either 208 V, single phase, or 240 V, single phase?
- 145
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1
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124
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Does a transformer have different primary and secondary PFs?
I tried connecting two energy meters on primary and secondary and found that they were showing different values when a load was connected to the transformer.
Does a transformer have two different PFs, ...
- 73
2
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2
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921
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Can I see a schematic for a 110 <-> 220 V power converter?
I would like to see a schematic for those 110 <-> 220 V power conversion transformers-in-a-box. I've read they are autotransformers (one winding with multiple taps). I'm using one to step up 110 ...
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1
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52
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Power 2 120VAC transformers with 220vac
In reference to the following.
(Connecting the primaries of two 110V transformers in series across 220V)
Putting 2 identical 120 VAC transformers in series in US. Having 2 Hot's and 1 Neutral if I ...
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1
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155
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DC voltage source in series with AC voltage
I am a bit confused with this circuit.
Assuming "i_x" is the left side current of circuit without the 3V DC source.
In steady state is i1(t)=(3/200)+i_x?
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1
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2
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496
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How can I work out maximum current on a DIY transformer?
I'm thinking about building a DIY transformer but I don't know how I would calculate the maximum current that the transformer can properly handle. I can't find an answer online because all the search ...
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1
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585
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Is it okay to use two step-up transformers together?
For part of a DIY inverter, I need to use a 12 V to 240 V transformer, preferably over 500 W. I couldn't find any suitable transformers to purchase, however, I found 12 V to 110 V and 110 V to 240 V ...
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2
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249
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How does this transformer work?
I've watched this latest video from Great Scott (relevant timestamp) and he came across and used this transformer successfully.
I tried to simulate it in a circuit simulator but I must misunderstand ...
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1
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596
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Speed control of a PSC induction motor, how does it actually work?
I'm trying to understand the physics and engineering behind speed control on PSC induction motors, usually seen in fans/HVACs.
I have come across this link, but I don't quite understand everything ...
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3
answers
166
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Simple transformer construction help
I’m trying to construct a small transformer to step up the audio of a crystal radio to line level. I can actually hear the radio faintly using a conventional earbud (not piezoelectric), but I’d like ...
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1
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667
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Pure Sine Inverters and Transformer Selection
So I'm trying to design a 24V to 110V pure sine wave inverter, which I'd like to be able to do 2000W to handle running my portable A/C on battery. I get the whole H-Bridge MOSFET concept, and even ...
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How to buy high-speed 220 VAC - 5 VAC transformer
I was reading this article https://www.etechnog.com/2018/06/How-mobile-charger-works.html and I was wondering how can I search and buy the specific transformer that AC-DC converters use to step down ...
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5
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281
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Doesn't the law of conservation of energy invalidate Ohm's law?
Imagine I have a power supply supplying a 12 amp AC current of 12 volts. The resistance of the circuit, consisting of only a copper wire and a resistor, is 1 ohm.
In this instance Ohm's law holds true:...
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1
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152
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Laptop AC adapter power cord [closed]
I suppose this is probably a stupid question, but my laptop was expensive so I want to make sure I'm protecting it well..
I ordered a second AC adapter for my computer, a used OEM one, but the cord ...
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-1
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3
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262
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In a DC power-supply design, is it safe to connect the GND of the secondary side of the transformer to the AC input part?
This is a design that my colleague was using to supply power to some op-amps in an accompanying AC voltage measurement circuit.
I'm wondering why the ground of the secondary side of the transformer (<...
-1
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1
answer
102
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14VAC to 11VAC (~200mA) Using a small transformer
I have an application that requires a transformer with 120VAC 60Hz on the primary and 7VAC/11VAC (200mA) on the secondary. Unfortunately, while this part is available in some countries I have not ...
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2
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98
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A couple of questions about transformers
1: I accidentally supplied 9v to a 4.5v - 0 - 4.5v transformer like this:
And it was working for a about a second and then it stopped and isnt working. Have i killed it?
2: Can you use a square wave ...
2
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2
answers
8k
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How to hook up a transformer to 120V AC?
I'm building a DC power supply and am stepping down my voltage from 120V (from the outlet) to 24V through a transformer. I will be soldering the 3 wires that plug into a North American electrical ...
1
vote
1
answer
117
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Homework: impedance equivalence with transformer
I am working on this homework problem and I am wondering if my approach for finding Zeq is correct.
I know my matrix is correct, but I feel like I need to do something else to find the correct ...
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