Jul 23, 2018 Transformer simulation Hi, I am having a hard time understanding the simulation results of this stepdown T/F. I am giving the primary an input voltage RMS of 8600V, T/F turns ratio 25:1 with Rprim=0.1ohm and Lprim=0.1H. 1.2 Needs of transformer short-circuit current calculation Today more than ever before, the electricity grid is developing so quickly — the power plant capacity, the substation capacity and electricity loads, as well as load density, sustainably grow. Take China as an example. The number of 500 kV substations in the.
Analysis of Transformer Circuits
We finished our discussion of transformer circuits in our last lesson when we were looking at the Zs. We came up with this formula that said the Zp=(Np/Ns)2*Zs. We're going to apply that in a circuit in just a moment but before we do that, I just want to mention a little bit about what is impedance. Impedance is … when we talk about resistance, impedance is a term that is commonly used to talk about resistance in an AC circuit. When you just say resistance, sometimes it can be applied to both. When we talk about impedance, typically we're talking about resistance in an AC circuit.
Let's look at, here have a transformer and a load and we're going to do a few calculations with this. First of all, this is the formula that we just came up with. We said that (Np/Ns)2*Zs would tell us the Zp. As I mentioned earlier, here we have 100 ohms in the secondary. Usually, the secondary resistance or impedance is a known value because you can see it right in the circuit. Let's do some calculations here.
The primary to secondary is a ratio of 10 to one. We would see 10/1 here. The Zs is one. We finished our discussion of transformer circuits in our last lesson when we were looking at the Zs. We came up with this formula that said the Zp=(Np/Ns)2*Zs. We're going to apply that in a circuit in just a moment, but before we do that, I just want to mention a little bit about what is impedance. Impedance is … when we talk about resistance, impedance is the term that is commonly used to talk about resistance in an AC circuit. When you just say resistance, sometimes it can be applied to both. When we talk about impedance, typically we're talking about resistance in an AC circuit.
Let's look at, here have a transformer and a load about 100. Let's see, do we have our calculator handy? If we say 12/100 we're going to get 120mA of current. We'll say 120mA. Let's calculate the power that's dissipated in this transformer. We would say … remember power is E*I. We will say 12v*12mA and let's see, what will that equal? We've got … just a moment here, let me get this back on track here. We would say we have 120mA*12v=1.44W. We have 1.44W.
Now, something we could do, we could take this value and use it to solve for what is the current and power that we have over here. We know that we have 120v applied. We know that we have 1.44W in the secondary. We know that 120v*whatever the current is, is going to equal this value because remember we said that the power in the primary equals the power in the secondary.
If we wanted to solve for I here, we could … well let's see, we could say 1.44W/120v, (120v*I)/120v and then, so we have 1.44W. Now something we could do, we could take this value and use it to solve for what is the current and power that we have over here. We know that we have 120v applied. We know that we have 1.44W in the secondary. We know that 120v*whatever the current is is going to equal this value because remember we said that the power in the primary equals the power in the secondary. If we wanted to solve for I here, we could … well let's see, we could say 1.44W/120v, (120v*I)/120v and then cancel 120v/120v and then I=1.44W/120V. Why don't we do that was our original power calculation?
Okay. We could have done that another way. It would have been a lot simpler actually. We went in and we … remember we went in and we calculated the impedance. We said that is was 10,000. Well, what we could have done, we could have just said 120v/10 [inaudible 0:06:21] and we would have gotten the same value, the 12mA. That would have been a quicker way to do it, but I wanted to walk through it showing the power calculations. But that does prove that our formula here actually does work.
Impedance of Secondary is Reflected to Primary
Now we've already actually mentioned this. Your text goes into this discussion so I'm going to allude to it. Transformers change voltage and currents depending on turns ratio. It only makes sense that if voltages and currents are impacted, resistance or impedance will also be impacted. The discussion follows on the next slide. Your text goes into the discussion about reflected impedance using the three illustrations to the right. They use these three illustrations. The point of the discussion is that as resistance changes in the secondary, current will also change and this change will be reflected in the primary.
Actually, we re-proved that in that last circuit, but the gist of that is that here they start out with a high resistance. The resistance goes down and then the resistance goes much lower. Well, what's going to happen, as a result of this changing resistance, current is going to increase in the secondary. If the current increases in the secondary then the current must also change in the primary. But the fact is that there's no resistor in the primary. The resistance that is experienced in the primary is a function of the turns ratio and the resistance that you see in the secondary.
As we mentioned here about the … remember how we talked about how the power in the primary causes the power in the secondary. If the secondary current goes up then the primary current must adjust. Okay, so let's do another calculation.
Transformer Calculations
Here we have … this is a virtual audio transformer. This is one from Workbench. This particular one has a 2:1 ratio. We're showing 169v here. Now that is a peak value. Actually, this is 120v if we consider RMS and this is what you would see out of the wall. That is actually if you measure it with an oscilloscope, that's what you would see as the peak value.
What do we want to do? We want … as a result of this changing resistance, current is going to increase in the secondary. If the current increases in the secondary, then the current must also change in the primary. But the fact is that there's no resistor in the primary. The resistance that is experienced in the primary is a function of the turns ratio and the resistance that you see in the secondary.
As we mentioned here about the – remember how we talked about how the power in the primary causes the power in the secondary. If the secondary current goes up then the primary current must adjust. Okay, let's do another calculation. Here we have … this is a virtual audio transformer. This is one from Workbench. This particular one has a 2:1 ratio.
We're showing 169v here. Now that is a peak value actually … let's see where, there's our calculator and if we say … what have we got, 120/200=600mA. We have 600mA here. If we wanted to calculate the primary power, we would take 120v*600mA. Let's take a quick look at that. 600mA*120v=72W of power. That should be the same thing that we're seeing in the secondary. Let's do our secondary calculation. Let's see. What we have is our voltage and we didn't even talk about the voltage in the secondary, but it's a 2:1 ratio. We have 120v. So it's going to be about 60v in the secondary.
If we take 60v*50?=1.2A and then remember to get power, we'll take that 1.2A*60v=72W. There we have it. We have the 72W in the secondary and 72W in the primary. Now on the next screen, I have … this is actually a MultiSim circuit that you see here. This is the same one that we just looked at right here. You notice the 169v here and the 50?. This is the same circuit.
MultiSim Simulation
I put a voltmeter in here and these are the actual values that Multisim gave. Notice it's 59.92v. Remember the input was 120v. The turns ratio was 2:1 and so 120v/2=60v. But you'll notice it's fairly close. Multisim is really quite accurate. The turns ratio was … so you would see a little bit of a drop here.
Then we calculated the power and in our calculation, we said that there was 72W. You'll notice here the calculation is very close. That's 71.39W. Now, if you do this simulation actually in MultiSim and you attempt to measure the current in the primary, that simulation that comes with your textbook, the circuits that they have, one of the circuits in this particular chapter … I had great difficulty in getting the multimeter to measure current in the primary. Sometimes simulations don't always work perfectly. What I have here is actually a wattmeter. In your MultiSim package, you do have a wattmeter.
Okay. Next item here.
Troubleshooting Transformers
In general common defects in transformers are, notice an open primary, an open secondary, shorted turns or shorted windings, windings shorted to the core, short between the primary and the secondary. In fact these four here we had talked about in previous lessons. This is not the only one that's new here, is a short between a primary and a secondary. That will end a transformer. Defects of a transformer can be detected by observation or by checking with an ohmmeter or a voltmeter.
Okay. On this section we looked at … mostly looked at some circuit calculations. In your homework, at the end of the chapter, you'll find you have quite a number of calculations that you can perform to get the feel of transformer calculations.
Hi folks! As you know that we have already shared an article about Android apps for Electrical and Electronics Engineers, Students and Technician. We have also shared online electrical and electronics calculators and iOS Apps for electrical Engineers and students for free to use on your smartphones.
Today, we will share online circuit design, schematic and simulation tools list for Electrical and Electronics engineers and students. I hope you will like it because these tools don’t need to download and install in your computer because it is on web-based tools. In addition, these all tools and apps are free to use and you can design, analyze and simulate any kind of circuit, module and project with multiple parameters.
If you find this post useful, then Please! Share with your friends. Thanks
Below is the list of free online Electrical & Electronics circuit simulation tools.
EasyEDA
For Electronic circuit design, circuit simulation and PCB design.
EasyEDA is an amazing free online circuit simulator which is very suitable for everyone who loves electronic circuit. EasyEDA team strives for bringing a complex design program on web-based platform for more than 5 years, and now the tool becomes wonderful to users. The software environment allows you to design schematic. Check operation by circuit simulator. When you make sure the circuit function is good, you can create printed circuit board with the same software. On the website you can find and use many projects and electronic circuits made by others because they are public and open hardware. There is a useful tutorial explaining the main features of the tool, which makes it easy to drive. It also has some pretty impressive import (and export) options. For instance, You can import files in Eagle , Kikad , LTspice and Altium Designer , and export files in .PNG, or .SVG.
DoCircuits
DoCircuits is an interesting as well as learning circuit design and simulation tool.
I bet you will like its function, especially graphics, i.e. unlike other tools, when you connect a component (say a bulb) in the circuit, you will see a bulb icon instead of symbols. With the helpf of this tool, you can build, run simulation, and analyses both electrical and electronics engineering (Digital and analog) circuits very easily and export your file as PNG. It also provides DC analyses, Time and frequency domain analysis with accuracy output level.
It is also free and doesn’t need to install in your computer. So don’t wait. Just give a try to DoCircuit because it is a web-based, i.e.online circuit design, simulation and analyzing tool.
CircuitLab
Click images to enlarge
CircuitLab is one of the easiest Electrical and Electronics Engineering circuit design and simulation tool I have ever used. In CircuitLab, you can analyze and simulate your designed circuit with different parameters such that DC simulation, DC Sweep, Time domain analysis and frequency domain simulations. Example of “555 Timer as Pulse Width Modulation (PWM) Generator” is shown in the 2nd (above) fig.
In addition, you can save/print your project as PNG, PDF, EPS and SVG, etc. Moreover, it supports to check a device, component and circuit modal graphically with all important factors.
CircuitLab is online and free to use in demo version in browser (because it is web-based) without installation in your computer.
PartSim
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Basic inverting operational amplifier circuit
PartSim is another great electrical and electronics circuits & network design and analyzing tool. It is a web-based (i.e. it doesn’t need to install in system and you can use it online in your browser) full featured and free of cost even you don’t need to create an account (while you can make one free to save your projects and models) to use it.
PartSim supports common analysis and simulation such as AC analysis, DC bias, DC sweep and transient response. It also displays a graphical waveform of electronics components and modules which you want to analyze in PartSim. In addition, you can save your designed or simulated circuit in PDF or PNG as well.
CircuitMaker
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CircuitMaker is a very useful and interesting circuit design and simulator for newbie’s as well as professional electrical and electronics hobbyists, students and engineers.
CircuitMaker is not just a free EDA software tool from Altium, it’s also a community of creative people and design content, working together to invent circuits and electronics products for a better future.
In CircuitMaker, you can design a professional PCB while working on a breadboard and PCB. The interesting thing is that you will use graphical electrical and electronics components and devices while the app will guide you with built in professional layout tools. Once you have done, then you can also edit your module/circuit and then share with your friends for taking review.
It is also provides Gerber (a file format, which provide detailed information on the PCB (Printed circuit board) conductive layers.
Also Read: How to Test & Fix the Printed Circuit Board (PCB) Defects?
In addition, you have to make a free account at 123D Circuit official site while using this free online tool.
Scheme-it
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Scheme-it (owned by digi-key now) is a very good designer and diagramming tool to design electrical and electronics diagrams, Power & Control diagrams, technical engineering schematics and symbols. It provides hundreds of electrical and integrated electronics symbols and components.
You can export your designed model in PNG and also share with your friends via e-mail and social media sites. Additionally, It is free and online electrical and electronics engineering tool and it doesn’t need to install it on your computer.
6. Removed: Was shutdown by the Owner.
Schematics
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This is another powerful circuit schematic, design and simulator online tool for web and mobiles. It provides professional grade Spice, Sub circuit & device modules, digital and analog parts, DC analysis, AC analysis, Transient domain time and OP analysis.
The positive sign is that they provide online circuits library where you can upload your designs to edit and share with others. You can also find new designs to download for your new projects. Both Spicy schematic and Spicy SWAN are fully free to use without restriction, but for unlimited use, storage modules and project files, you have to upgrade the tool in your account.
DC/AC Lab
This Electrical and Electronics engineering circuit design and simulation Tool is under construction. Once they are done, we will update you via this page. Stay tune.
Update: This circuit is live now, but student have to pay $2.5 per month if you wanna use.
It has visual and attractive graphics, but limited circuit simulation. It’s definitely a great program for teaching, very easy to use. it makes you see the components as they are made. It does not allow you to design the circuit, but only to make practice.
GnuCap
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GnuCap is a general purpose, analyzing package. It is not based on Spice but it can perform Fourier analysis, transient analysis, AC and DC Circuit analysis. User can also design different electrical and electronic circuit. Moreover, it is free and web-based, i.e. online simulation tool.
Upverter
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Upverter Schematic Capture editor is a comprehensive and very easy to use for designing electrical and electronic circuit diagrams and schematic. It allows multiple designers to work on schematics together in real time with customizable design and it is fully collaborative.
In Upverter, designers can create breadboard layout, capture design and schematics and also exports Gerber (a file format, which provide detailed information on the PCB (Printed circuit board) conductive layers.
It doesn’t require any download or installation because it is an online tool, i.e. it runs in your browsers. But firstly, you have to make a free account on the Upverter official website.
EveryCircuit
it is an electronic simulator online with a well-made graphics. When you enter the online program and it will ask you to create a free account so that you can save your projects and have a limited portion of the area to draw your circuit. To use it without limitations demanding an annual fee of $ 10. It can be downloaded and used on platforms of Android and iTunes. The components have a limited ability to simulate with spice minimum parameters. Very easy to use, it has a great system of electronic design. It allows you to include (embed) simulation into your web page.
Lots of free circuits and projects are available to edit in the editor with animation as well. BUT, you have to run this simulator in the Chrome browser.
TinaCloud
This simulation program has sophisticated capabilities. It allows you to simulate, in addition to the normal mixed-signal circuits, microprocessors also, VHDL, SMPS power supplies and radio frequency circuits. The calculations for electronic simulation are performed directly on the company server and allow an excellent simulation speed.
Thank you so much for reading and sharing this post with your friends. If you realize there is something we missed, or if you want to add another online simulation tool in this list, leave a comment in the below comment box and we will add it in this post. Once again Thanks
Also read: What is LabVIEW and How to make basic Electrical Projects in LabVIEW?
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