Good day, I have a transformer with 24 volt DC output, but the voltage increases from time to time, I want to design an lc circuit to dampen these spikes to 24 volts. Below is a circuit I designed but I'm not sure if it works. What is your comment?
The transformer i use:
If you want to find out if it works in theory, firstly think through if it is conceptually appropriate (i.e. what does an LC filter do exactly, how does it respond to transients), and the verify it, you could simulate it by configuring your 24V source as a constant 24V with a waveform superimposed onto it. I know how to do it in LTSpice since that's what I use, but it looks like you're using a different tool.
But let's start at the basics - what kind of 24V power supply is this, where do the spikes originate from, and how high, long and frequent are the spikes exactly?
Ok, I see you uploaded a photo of the transformer (part of it). Looks like a simple transformer with a bridge rectifier and a single filter capacitor, so no RC or LC filtering. With no load applied, it will likely output significantly more than 24V, with a load applied it may sink to 24V and even below (modulated at grid frequency; i.e. ripple) and with a load that is not constant, you will get a combination of that.
Yes, an LC filter is one possible approach, but quite frankly, this is 2021 and except for tube amplifiers and common-mode HF LC filters, we don't see them all that much anymore, just like linear (transformer-based) power supplies. Good reason too - they're relatively costly and bulky.
Playing the devil's advocate here: why not get a 24V SMPS? It'll be small, most give a pretty clean output as they are which can be cleaned up further with fairly small components (since their switching frequency is usually around 30-50kHz) and they're cheaper than a single transformer.
I simulated the circuit using easyEDA, I have no idea how often it happens.
When I connected a 24/5v regulator to this transformer, I saw that it broke down, then I solved this problem by adding a capacitor to the input, but I think designing a low-pass filter circuit for the output is the definitive solution.
i want to integrate it into an industrial board sorry i have no choice 
It's wrong to use a 5V linear regulator from a 24V transformer & bridge rectifier power supply.
It produces 2W of heat even with a current of only 100mA.
The reason it broke is probably there.
This doesn't solve if may you attached the filter.
Okay; to properly dimension an LC filter you will need to know the input ripple (amplitude + frequency), desired output ripple (amplitude) and required output current. Otherwise you're stumbling in the dark. So you really need to figure out what the output of that existing power supply looks like under the conditions it's used in.
Does this transformer power other equipment besides your own circuit? This will likely complicate matters.
I know (remember) what you say about integrating into an industrial board, but you're setting yourself up for unnecessary challenges here in my opinion. If you can add a module to the industrial setup, you can likely also add another SMPS. Do you actually need 24V, or do you actually need 5V or 3.3V logic? If so, very small footprint AC/DC power suppliers are available, or you could use a DC-DC buck converter.
The main issue with your question (also the previous one from about a week ago) is that any solution that's offered is shot down by you because you don't share the full set of requirements and constraints right from the start. That makes it difficult to guess what might work for you. I'd suggest you put some more time into accurately describing what the case study is, what your requirements are and within which limits/constraints you need to operate. Otherwise this is going to be a very long and tedious process.
no no i am not using linear i am using step down i think i need to add the link: https://www.robotistan.com/voltaj-dusurucu-regulator-karti-d36v6ahv-pl-3799
I opened a form for a problem about this last week, but as I said, I solved this problem by adding a capacitor to the output of the transformer. I am using an industrial panel and I want to connect a gateway that I designed myself to this panel. The transformer is connected to many places in the panel such as plc. I need to feed this gateway from transformer. I have a 24 / 5 volt step down dc-dc converter in my circuit, but when I connect it like this, it breaks my regulator, so I want to add a low-pass filter.
yes, I am aware that there are many unknown situations, but I am looking for a solution.
Like I said, if you want to filter out noise and/or ripple, you'll need to specify it. If you don't know what killed your DC-DC converter, it's not possible to suggest a reliable solution.
In an environment where the step-down converter that can input up to 50 V was broken, it cannot be dealt with without more detailed analysis data using an oscilloscope etc.
That is also needs for calculating each value for the design of the LC filter property.
When I connect this gateway to other boards, it is impossible to calculate the conditions for each of them one by one, isn't it possible to have a filter circuit like plc that will adapt to every situation?
No. For all we know, your problem may not be positive spikes, but e.g. recurring negative spikes for instance as a result of inductive loads without proper snubbing/protective diodes being switched.
The only fail-safe solution would be to include a separate power supply for your own logic board/module. If you have space for an LC-filter, you should also have space for a small SMPS.
This is the dc/dc regulator I use, they wrote smps.
Other Link : Pololu - 4-25V Adjustable Step-down Voltage Regulator D36V6AHV
Do I need to use do this regulator?
Lacking all the critical information I have indicated before, I have no advice to offer. I honestly don't know what you need because the important parameters are unknown.
thank you anyway...
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