hybridfree/eevblog-posts huggingface dataset:
do you know this inductance with three wires - Page 1
Forum section: electronics / general

author: iso14000
author_rank: Contributor
timestamp: May 30, 2023, 04:44:22 pm
content: Hi folksI have , from a former teardown, this inductance in a drawer.I decided to measure it .with L/C ringing after a voltage ramp up I found a quite large inductance : 4 Henry, for ESR of 4 ohms between two wiresthe third wire seems almost shorted one the two that exhibit an inductance behaviorThis (large) inductance comes from a UPS that gived up, and I was surprised to find it , thinking of chopper filterthe question is : do you have an idea about the third wire?

author: TimNJ
author_rank: Super Contributor
timestamp: May 30, 2023, 05:44:25 pm
content: Depending on the topology it was used in: Some sort of tapped inductor? Do you measure any inductance between the third wire and some other wire?4H seems pretty large though! Feel like I'm off.For example:

author: Andy Watson
author_rank: Super Contributor
timestamp: May 30, 2023, 07:11:07 pm
content: Probably a custom part made to order. Looks like rasmi are still in business:https://rasmi.com/Does the type number align with any of their current products?Magnetic amplifier ? Auto-transformer ?

author: iso14000
author_rank: Contributor
timestamp: May 30, 2023, 08:33:53 pm
content: Hithanks both of you.at the beginning I didn't believed my RLC meter (a creepy one) , so I used the good old method to make ringing the L by a known C, and I found the L=4H.....yeslike you.after reading your comments, I did some extra investigation, and Yes it looks like a tapped inductor.I found a transformer effect by a 1:5 ratioI'm puzzled about the utility for such a thing...If i remember well, that UPS used 2x12V lead acid , so I guess by this ratio , a chopper could give 24*5=120V.... but here in europe we are set with 230Vrms....

author: floobydust
author_rank: Super Contributor
timestamp: May 30, 2023, 09:21:22 pm
content: It might be wired as an autotransformer, to provide a fixed voltage boost to cover line voltage sags. I have seen that in UPS as well.I would inject say 6-12VAC into a winding and see what comes out.

author: iso14000
author_rank: Contributor
timestamp: May 31, 2023, 09:09:19 am
content: it is exactly what I did, 1Vrms on the "primary", I measured almost 5.5Vrms on the "secondary"unless, I didn't catch it... and the DC section was supplied by 3x12V lead acid. so 36V where available.and with a boost tapped , with a n~5.5 , let's make a 0.5 D.C. the output voltage should be 7.5*Vin so =>270Vthe latter isn't so far from 230*1.414=>325.... probably DC is a little higher...I beleived tapped structures suffer of leakage inductance issue...thanks guys!
415 3phase AC to  DC - Page 1
Forum section: electronics / general

author: JoeyG
author_rank: Regular Contributor
timestamp: May 30, 2023, 03:22:51 am
content: Using a 3phase full wave diode array to convert 415VAC 3phase to a single DC output. What is the maths to convert to the max peak voltage?Is it 415 * SQRT(2) = 415* 1.414?

author: trobbins
author_rank: Frequent Contributor
timestamp: May 30, 2023, 06:55:51 am
content: Perhaps best to link to an actual circuit you want to apply this to, as there are a few ways to refer to 3-ph full wave rectification. Eg. 3-phase (no neutral) with diode bridge is perhaps most common. Suggest you go through a decent reference like "Rectifier Applications Handbook" by On-Semi.

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 30, 2023, 11:15:13 am
content: Yes, peak will be rms * sqrt 2 for the usual 6 diode arrangement.
Whats wrong with Power Integrations Buck? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: May 31, 2023, 07:07:46 pm
content: Hi,Why is this attached Buck deemed to be so bad? (100-265VAC input, 24vout 17W out)The LNK3209 is run within its current and voltage rating.The inductor is within ratings.The SiC diode within ratings.The circuit will have loads of blown air over it all the time.So why is it deemed a no-go'er?LTspice and jpeg attachedLNK3209https://www.power.com/sites/default/files/documents/linkswitch-tn2_family_datasheet.pdf

author: floobydust
author_rank: Super Contributor
timestamp: May 31, 2023, 07:44:12 pm
content: What does "so bad" or "no-go'er" or "wrong with" mean as far as power electronics, science and technology?Have you considered transitioning to a different field of expertise, it could make life much easier. I also see you on Power Integrations forums, can they help?C9 CBPmust be 0.1uF at voltage but it also sets current limit. Did you use a cheap tiny part there, something from the bowels of guangdong?Not sure D1 is shown as slow 1N4005 and Vf to match D2 as far as regulation goes.

author: Faringdon
author_rank: Super Contributor
timestamp: June 01, 2023, 05:48:18 am
content: Thanks, the people who make the chips wont tell us any electrical reason, but just tell us not to do it...we are under pressure to do it this way as its cheaper.The only elec reason we can think of is if the diode was not SiC...but we use SiC.

author: dmills
author_rank: Super Contributor
timestamp: June 02, 2023, 09:08:05 pm
content: Going off datasheet is ok as long as you respect the ratings, but even then if the silicon vendors FAE tells you not to do something, you are well advised to take that as a hint.Particularly with highly integrated high voltage power supply parts like the PI stuff, they are often a bit weird and you really want to follow the app notes because they have likely NOT been well characterised except in those limited number of circuits.What is the opamp and weird LT thing supposed to be doing, the PI part uses the match between the two diodes to regulate in this configuration so I am a little unclear as to what that additional loop is supposed to do, or even how it is closed?Unless you want to spend ages with a 'badly behaved mains' simulator and loads of blown out sand, I would be taking the hint, but then I like my stuff reliable.

author: Faringdon
author_rank: Super Contributor
timestamp: June 03, 2023, 10:36:03 am
content: Thanks, yes the sim is just my attempt to get the on/off type controlled method of the lnk3209 in LTspice, without me havign an actual proper model for it.
Is anyone familiar with "Solis" hybrid inverters? - Page 1
Forum section: electronics / general

author: Freesurfer
author_rank: Regular Contributor
timestamp: May 29, 2023, 05:58:49 pm
content: I have been a fan of Victron Energy products for a long time. They make a lot of equipment that is suitable for things like UPS, off-grid, RV etc, but they do not (afaik) have any grid-tie systems intended for selling PV power back to the grid. For some time the marked has been a bit divided where some manufacturers only make batteryless "grid tie oriented" inverters, while others like Victron only make "battery oriented" off-grid inverters. So depending on the use case you'd either go with the one or the other group of manufacturers.However recently I noticed that one of the retailers I order equipment from, has a Solis hybrid inverter that seems to close the gap and bring both features into the same product. It is mainly intended for grid-tie operation to sell PV back to the grid, but it also has an option for a battery bank so you don't need to rely as much on the grid when there is no sun. But even then, it also doubles with a "UPS mode" where it will work more like an off-grid system. It does not shut down on loss of mains like an ordinary grid-tie inverter.On top of that, when I compare the price of the Solis inverter to a similarly specced Victron inverter, the Solis inverter is only like 60% of the cost of a victron system. Much cheaper, and with the benefit of extra features.https://www.ginlong.com/energy_storage_inverters8/3_6k_s6_l_gl.htmlIn my case I don't really need it for the grid-tie features other than to recharge the batteries from a generator when needed. But it might come as an extra bonus if I ever repurpose the inverter for something else.I wonder if anyone has got any experience operating them mainly as off-grid and if there are any limitations that I should be aware of, considering it is mainly intended as a grid-tie product. Normally I'd probably get something from victron, but the lower price point made me curious.I also wonder if anyone has any experience with Solis inverters in general and if they are of good quality, and if the performance claimed in the datasheet can be trusted or are boasted beyond what they can truely deliver.Anyone? :-)

author: fourtytwo42
author_rank: Super Contributor
timestamp: May 30, 2023, 09:00:38 am
content: Tryhttps://diysolarforum.com/
Bootstrap drive for two transistor forward - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: May 28, 2023, 10:26:13 am
content: As you know, Two tran forward was never a candidate for bootstrapping, since it has no "pushpull" drive for the bootstrap cap refresh.However, the attached shows its easily possible.Since modern bootstrap drivers, like 2ED2109, have immunity to -11V on the Vs pin, and CMTI of 50v/ns, then why do people still use gate drive transformers for the high side drive?2ED2109https://www.infineon.com/dgdl/Infineon-2ED2109-4-S06F-J-DataSheet-v02_32-EN.pdf?fileId=5546d4626cb27db2016cb8d7493e29eb
portable power stations - Page 1
Forum section: electronics / general

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: May 01, 2023, 04:08:56 pm
content: NEXPOW Portable Power Station 2000W/2400Wh LiFePO4 Lithium Battery Pack, Solar Generator (Solar Panel Not Included) with Anderson Interface.Been looking at these types of power systems.Want to use on to power just a corner of my house (big screen TV, Dish Network sattelite box, DVD player, and use solar panels to recharge it.Any suggestions on the best ones?Thanks,Corby

author: Nassau Cable
author_rank: Newbie
timestamp: May 25, 2023, 07:55:47 pm
content: Hello, you can also read aboutVigorpoolsolar captain, it is a good brand as well. Another recommendation is to go for systems with lithium batteries, like the NEXPOW Portable Power Station with LiFePO4 battery, as they are efficient and long-lasting.
Resonant Inverter: Amplitude to Voltage? - Page 1
Forum section: electronics / general

author: johnywhy
author_rank: Contributor
timestamp: May 20, 2023, 01:29:36 am
content: I've read the Voutof a resonant inverter is lowered by increasing the oscillatorfrequency, pushing it above the resonant frequency of the LC tank.Instead, why not lower Voutby reducing theamplitudeof the square input oscillator, (and keep frequency the same)?

author: johansen
author_rank: Super Contributor
timestamp: May 20, 2023, 05:34:35 am
content: The whole point of a resonant converter is to use switches to modulate a system under easy to switch resonant conditions.Keeping above the resonant frequency is easier because you dont have diode recovery in the body diode of the igbt or mosfet to deal with.You can decrease the power transfer by droppin below the resonant frequency as well as above.

author: temperance
author_rank: Super Contributor
timestamp: May 20, 2023, 09:33:47 am
content: This should clarify most of your questions concerning resonant power supplies:https://www.youtube.com/playlist?list=PLMZ8LHWk_2jjYz1gM9x3dpLOb3E8GLVBq

author: johnywhy
author_rank: Contributor
timestamp: May 20, 2023, 09:51:27 pm
content: Quote from: temperance on May 20, 2023, 09:33:47 amSam's great. I've watched a lot of his videos, but i don't always understand them.Was there a particular video that explains why we don't vary amplitude to adjust Vout?Thx!

author: johnywhy
author_rank: Contributor
timestamp: May 20, 2023, 10:00:10 pm
content: Quote from: johansen on May 20, 2023, 05:34:35 amSounds like an answer to meYou're saying that, reducing pulse amplitude will cause diode recovery in the body diode of the igbt or mosfet?I understand thatraisingfinis preferable, because if you lower fin, then harmonics of fincould sweep down into the passband of your resonant LC tank. Correct?

author: johansen
author_rank: Super Contributor
timestamp: May 21, 2023, 05:16:45 am
content: Pulse width stays the same. Amplitude is always the same. The switch is fully on or fully off. Anywhere inbetween is losses

author: johnywhy
author_rank: Contributor
timestamp: May 21, 2023, 05:05:29 pm
content: Quote from: johansen on May 21, 2023, 05:16:45 amRight, of course, the switch must be fully on or off.But you could vary the power supply.

author: Weston
author_rank: Regular Contributor
timestamp: May 21, 2023, 06:24:03 pm
content: Are you talking about a dc-dc converter using a resonant topology like LLC? Or an inverter with an AC output used for something like induction heating?Either way, the same point applies:One of the main goals of a power supply is to regulate the output with a varying input voltage.You could regulate the input voltage and still use the resonant inverter, presumably to generate AC or to provide power across an isolation barrier. You are entirely correct in your understanding that it could be done.However, this would require an additional power converter to adjust the input voltage. From a complexity and cost standpoint this is worse than just using the inherent frequency/amplitude characteristics of the resonant inverter.
Paralleling solar panels - Page 1
Forum section: electronics / general

author: uer166
author_rank: Super Contributor
timestamp: May 17, 2023, 06:44:30 am
content: I know better not to do it, but I have 10 panels with Vout of 65V each. If i have one string, that is 650V, if two, then 325V. In either case, the price of a total of ~3kW of MPPT capacity is very high for whatever reason. The cheap MPPTs seem to top out at ~250V PV.So, what are the downsides of paralleling say 5 (or 10) 325W panels, all in identical conditions/temperature, and no shading?

author: Jeroen3
author_rank: Super Contributor
timestamp: May 17, 2023, 07:20:16 am
content: The input current of an MPPT is also limited. Typically around 15A.Paralleling solar panels requires different strategies for power tracking and is uncommon.I can buy a 3kw growatt with 360 Vdc nom input for less than 500 euro.Three phase output inverters can typically handle higher dc inputs.

author: uer166
author_rank: Super Contributor
timestamp: May 17, 2023, 07:41:08 am
content: Quote from: Jeroen3 on May 17, 2023, 07:20:16 amIn a non-isolated buck, the input current handling should be same as output, would it not be? All the ones I'm looking at are 40-60A output non-isolated buck MPPTs. 500 Euro is eye-watering for this application. You're right about the panels, it's a totally different optimization..

author: Jeroen3
author_rank: Super Contributor
timestamp: May 17, 2023, 07:57:13 am
content: You are looking for a DC/DC application?

author: tautech
author_rank: Super Contributor
timestamp: May 17, 2023, 08:23:18 am
content: Quote from: Jeroen3 on May 17, 2023, 07:20:16 amYet the Morningstar ones I remotely monitor are rated to 60A. Commonly see them from 2 and 3 panel arrays charging at 25A.While double checking that online I notice they have a new 600V product also rated to 60A.https://www.morningstarcorp.com/products/tristar-mppt-600v/

author: uer166
author_rank: Super Contributor
timestamp: May 17, 2023, 08:33:31 am
content: I should have been more clear, it is a lithium battery application (12s Li-Ion battery) charging.

author: Siwastaja
author_rank: Super Contributor
timestamp: May 19, 2023, 01:02:46 pm
content: Is it not an option to buy two of the cheap controllers, paralleling their outputs at the battery instead? That would work the best. If this is too costly, you would save even more if you just did not buy (or sold if you already have them) half of the panels, making a smaller system. The problem with paralleled one is it gives less bang for a buck as it's likely working suboptimally all the time. Of course you get more energy than from a half-sized system, but probably not even near the double, but the panels, their mounting and the location still has cost.

author: uer166
author_rank: Super Contributor
timestamp: May 19, 2023, 03:04:00 pm
content: That's exactly what I went for, with a bonus that it adds quite a bit of redundancy. I had to get four (4)! units where each can handle only 2-3 panels.Each being 40A is over-provisioned by about 4x, but that's still way cheaper than a single HV string MPPT.
CAN BUS error on my ebike due to squeezed cable? - Page 1
Forum section: electronics / general

author: T_guttata
author_rank: Regular Contributor
timestamp: May 19, 2023, 09:56:56 pm
content: HiI have an e-bike, which uses a MAHLE X35 hub drive. Unfortunately, the motor cable was squeezed by accident. Since then I get an error message (HALL_SENSOR_FAULT #).I thought that I could repair the cable (solder it), but there is no wire cut (see image).According to a manual I found, the motor uses the CAN BUS interface:https://mahle-smartbike.com/wp-content/uploads/2023/03/MAHLE_X20_UserManual.pdfSince I'm not familiar with CAN BUS, I have a few questions.Is it possible, that a squeezed cable alone (no short circuit) can lead to errors? If so, why? Which property of the cable changes due to squeezing it?Is there any chance to fix it?How can you do proper diagnosis in such a case?Your help is appreciated! If I can not fix it, I have to get a new motor for $400. Would be very sad to dispose the whole motor because of that.Regards

author: langwadt
author_rank: Super Contributor
timestamp: May 19, 2023, 10:43:36 pm
content: just because there isn't a visible break doesn't mean there isn't a breakget out the multimeter and some needles and try measuring each wire from end to end

author: Siwastaja
author_rank: Super Contributor
timestamp: May 20, 2023, 05:15:20 am
content: Of course it can be CAN, but to me HALL SENSOR FAULT sounds like what it says - hall sensor failing. Probably this specific message comes through CAN, and CAN is checksummed so stops producing data completely instead of producing corrupted messages, so I don't think there's anything wrong with CAN. So start by doing the obvious, checking the hall sensors - which are prone to failure because they are installed and wired at the motor, in highest vibration environment.

author: f4eru
author_rank: Super Contributor
timestamp: May 21, 2023, 05:21:54 pm
content: squeezed cable likely made a short circuit between wires that damaged either the sensor, or the counterpart circuit, etc...
Quote for offline PSU? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: May 13, 2023, 12:36:36 pm
content: Hi,Know of a huge co at the mo' who are stuck for who to send their spec to, for getting an offline PSU quote.Is there not a "PSU quote central?"Its some 300-400W pk ~200W avLots of full to no load transinets and vv100-265VAC37-42.4VoutFor household consumer product....We know ofMeanwellStontronicWho else?

author: Gyro
author_rank: Super Contributor
timestamp: May 13, 2023, 02:36:44 pm
content: Quote from: Faringdon on May 13, 2023, 12:36:36 pm

author: Faringdon
author_rank: Super Contributor
timestamp: May 13, 2023, 05:01:38 pm
content: We had a boss of another co visit our boss once...and they both were saying what PSU's they had bid for.....they both knew of the same "SMPS_wanted" adverts...........so there is obviously some website where people can submit their requirements.The two boss's concerned here, both acted on bahalf of their respecitve Chinese SMPS design/manufacturers.I also know that Stontronic act as a go-between for co's wanting smps designed, and their widespread circle of Chinese manufacturer/designers.
Which is best for radiated EMC? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: May 12, 2023, 06:47:09 pm
content: Hi,Two isolated offline SMPS's, 40Vout.They both feed load which is sudden ON/OFF.....2ms ON, 2ms OFF..repeat..(400W when ON)Top one has higher di/dt in the 1 metre cableBottom one has higher dv/dt in the 1 metre cable.Which one performs worst at Radiated EMC compliance testing? (EN55032)(LTspice sim included)
Calculation of magnetising inductance (app note SLUP114) - Page 1
Forum section: electronics / general

author: insanoff
author_rank: Contributor
timestamp: April 27, 2023, 01:18:39 pm
content: Hello there,I am currently learning the basics and techniques of current measurement. I came across a very informative application note from TI (SLUP114, link is attached below). In the "Current Transformers" section, I followed the steps of the practical example calculation of current transformers. However, the calculation of magnetising inductance in step 4 seems misleading. I attach an excerpt from the note. The value of the cross-sectional area used in the formula must be 0.21 cm2. I suspect that the formula is also wrong. Instead of 10-9, the multiplier should be 10-8. Or have I overlooked something?I am also attaching the calculator spreadsheet that I created.Thanks!https://www.ti.com/seclit/ml/slup114/slup114.pdf

author: Faringdon
author_rank: Super Contributor
timestamp: April 29, 2023, 11:03:55 am
content: i woudl break everything down to base units then re-do it.The equations to work with areReluctance = lm/(uo.ur.A)N.I = H.dl (amperes law)L = N^2/Reluctance

author: wrangler
author_rank: Newbie
timestamp: April 29, 2023, 10:39:30 pm
content: You are correct, there is an error in the "step four" example. May I recommend SI units, always? With modern technological aids, such as Excel, there is less reason to stay with convenience systems such as CGS.

author: insanoff
author_rank: Contributor
timestamp: May 11, 2023, 08:04:40 pm
content: I have found a good source that also shows the units:http://www.mhw-intl.com/assets/CSC/CSC%20Design%20Formulas%202011.pdfThe updated calculator is also attached here.Thanks all for responses!
Vout of offline Buck shoots up - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: May 08, 2023, 12:46:01 pm
content: Hi, In AN-70, page 29, it shows the vin of the LNK3209 going down to 50V...at which point, the LNK3209 appears to malfunction, and its vout shoots up to nearly 50V, when its supposed to be 15V.It says a 100R/Zener circuit can be used to mitigate this....but without knowing for how long the FET turns on for, during the malfunction, how are you supposed to know how to size the 100R and the 20V zener?We worry because a temporary brownout could see vin going down to sub 50v.It looks like there's some 1V over the 100R when below 50vin...so thats 10mA...but can you be sure this is always the case?AN-70https://www.power.com/sites/default/files/documents/an-70_linkswitch-tn2_design_guilde.pdf

author: Algoma
author_rank: Frequent Contributor
timestamp: May 08, 2023, 03:44:09 pm
content: Only in a no-load output and low input voltage condition, according to the manual.The LNK3209 does shows a VIN_MIN of 30V for a 15V output. That Zener is likely only there to pickup transients on the output as the converter starts up. As long as your brownout remains above that 30V VIN_MIN, The zener likely only needs to handle the breif transitions between startup and shutdown.Non Isolated High Voltage converter. Seems sketchy. If your input is often in an actual brownout state, that causes overvoltage on the output, then perhaps a better converter is in order. or an overvoltage protection IC. Worst case is that zener overheats and fails short, putting the 100 Ohm permenantly across the output, or fails open and looses the overvoltage protection. Size the Zener voltage to protect your output, and the Resistor to protect the Zener at the VIN_MIN of the LNK3209.
What does the transient response of a battery look like?  - Page 1
Forum section: electronics / general

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: May 18, 2023, 05:45:34 pm
content: If you have a battery, and you have a sudden load increase (which the battery can support), what does the transient response look like? I can't seem to find many resources on this topic. Thanks.

author: David Hess
author_rank: Super Contributor
timestamp: May 18, 2023, 06:07:43 pm
content: The battery can be modeled as several large capacitors with series resistances.

author: Siwastaja
author_rank: Super Contributor
timestamp: May 18, 2023, 06:38:52 pm
content: Voltage source with series resistance with large temperature and state-of-charge dependency, with parallel large-capacity (think about tens of thousands of uF if not more) capacitors with somewhat less series resistance with less temperature and state-of-charge dependency - i.e., can supply current with less voltage drop for short times, tens of milliseconds, and AC impedance real part shows less variation as function of state-of-charge than DC resistance measured at multi-second timescales.On top of this, add some inductance, basically from the physical measurements (use some kind of loop area approximation).

author: Gregg
author_rank: Super Contributor
timestamp: May 18, 2023, 10:22:27 pm
content: You may want to start with a search for "battery coup de fouet" which mostly discusses lead-acid batteries. Basically it takes a little time for the chemical reactions to produce a heavy discharge from an steady equilibrium state.
Ecodesign directive for offline SMPS - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: May 04, 2023, 06:00:54 pm
content: Hi,Ecodesign directive for offline SMPS says our isolated 100W, 24Vout SMPS must have standby power of <0.21W.Do you know if this is actually a legal requirement?

author: TimNJ
author_rank: Super Contributor
timestamp: May 05, 2023, 12:49:12 pm
content: Yes:https://eur-lex.europa.eu/legal-content/EN/TXT/?toc=OJ%3AL%3A2019%3A272%3ATOC&uri=uriserv%3AOJ.L_.2019.272.01.0095.01.ENG
Inside a Powerpal smart meter reader - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: May 05, 2023, 06:35:14 am
content: Doubtless there are other versions of this in different parts of the world. Here we have this thing called a Powerpal and it is triggered by the winking LED on a smart meter and displays and graphically records the wattage and accumulated kWhrs on a smart phone or tablet. Mine conked out after 2 years and 2 months so they sent me a new one. The batteries in the old one were dead flat. Pity they aren't user-replaceable. Anyway, managed open it up (not easy!) for a look-see.

author: Someone
author_rank: Super Contributor
timestamp: May 05, 2023, 06:46:44 am
content: Quote from: Circlotron on May 05, 2023, 06:35:14 amHard to justify the "smart" adjective/modifier if the meter doesn't have a wireless protocol built in.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 05, 2023, 06:50:51 am
content: Quote from: Someone on May 05, 2023, 06:46:44 amSmart (meter reader) for dumb meters
S8474 WIRELESS POWER TRANSMITTER CONTROL IC from ABLIC - Page 1
Forum section: electronics / general

author: hilper
author_rank: Contributor
timestamp: May 05, 2023, 01:22:39 am
content: HiI 'am looking into thisS8474 WIRELESS POWER TRANSMITTER CONTROL IC from ABLIC (S8471 is the corresponding RX IC), pls see the attached file.Do anybody know, what this circuit / "Power Converter Topology" is called ?BR
Full bridge phase shift zvs converter waves explanation  - Page 1
Forum section: electronics / general

author: analityk
author_rank: Regular Contributor
timestamp: May 03, 2023, 11:33:34 pm
content: Hi everyone,I have circuit build's from MOSFETs full bridge that drive primary side of transformer connected in series with capacitor (this is EE32/16/9 core, 330nF cap, 20 turns in primary, 10 turns on secondary connect to full bridge rectifier and capacitor). Two car blub in parallel work as load on secondary.On one wire from secondary you can see current transformer, with 100 ohm resistor. Signal from this current probe is presented as violet line on scope. Two next blue and yellow lines presents voltage on drains on two lower MOSFETs in bridge.First question is about zcs condition. I think if current is switched in peak and it is resonant frequency so voltage on drains will be close to zero during switching.Next question is why I can not find similar current to voltage relationship in any publications.Picture was taken when phases was shifted by 180 degrees. (max power transfer conditions). [ Attachment Invalid Or Does Not Exist ]

author: analityk
author_rank: Regular Contributor
timestamp: May 03, 2023, 11:37:59 pm
content: Scope screen during work. I have no idea how attachments work here so if any mod can connect my post it will be nice.

author: analityk
author_rank: Regular Contributor
timestamp: May 03, 2023, 11:40:17 pm
content: setup here
Offline Buck converter input filter - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: June 05, 2023, 06:56:02 pm
content: Hi,Would you agree that the EMC performance of the two Bucks shown will be the same.(A) and (B) are the same apart from the bits ringed in circle/oval.However, (A) will have slightly better mains transient immunity than (B)...(due to the input filter inductor having a capacitor either side of it.)Would you agree?LTspice and jpeg attached.

author: f4eru
author_rank: Super Contributor
timestamp: June 05, 2023, 07:29:09 pm
content: Quote from: Faringdon on June 05, 2023, 06:56:02 pmNope.

author: ConKbot
author_rank: Super Contributor
timestamp: June 06, 2023, 02:08:47 pm
content: Quote from: Faringdon on June 05, 2023, 06:56:02 pmStop that. Jpg garbles text, and bleeds color into adjacent pixels as it's meant for photographs. PNG uses color palettes and lossless compression so on an image with just a few colors like a schematic, it comes out just as crisp as it was originally, and generally a smaller size, with no jpeg artifacting crunching the text.
Atmospheric discharge protection for low voltage offgrid PV system - Page 1
Forum section: electronics / general

author: ambrozy
author_rank: Contributor
timestamp: May 03, 2023, 11:37:00 pm
content: I'm building an offgrid PV system that consists of 2KW array of solar panels with ~90V MPP voltage connected with 90m long power line which is mounted 1m above ground to battery charger with 16s 234Ah li-ion pack. What would be sufficient atmospheric discharge protection system? I am mainly concerned about induced currents in this power line. Lightning strikes closer than 500m from the installation are rather unlikely and usually strikes are >1000m away.
Bad use of triple insulated wire - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 21, 2023, 11:50:39 pm
content: Hi,Today i was pulled up for using triple insulated Litz wire (TEXELZ) in secondary of a 24W offline flyback.It did not need 3000VAC isolation, but just 1500VAC.They said i should not have used the 3000VAC Litz.The thing is, there is no such thing as Double Insulated Litz wire? (rated for 1500VAC)..I know you can get it but its nowhere near as cheap and common as TEXELZ?

author: jpanhalt
author_rank: Super Contributor
timestamp: April 21, 2023, 11:53:22 pm
content: Just what were you "pulled up" by? Is that some sort of Brit slang? Last week, as I recall, you didn't know what "triple insulated" meant.

author: langwadt
author_rank: Super Contributor
timestamp: April 22, 2023, 12:18:41 am
content: Quote from: jpanhalt on April 21, 2023, 11:53:22 pmit is all made up anyway ..

author: jonpaul
author_rank: Super Contributor
timestamp: April 22, 2023, 02:45:46 pm
content: in 50 years of SMPS, EBU design experience I never used such exotic wire.Good engineering solutions are simple, available and cost effective. Just my design philosophyWe used normal copper wire, not litz, or Cu foil, or bunched wireInsulated by UL rated mylar tape eg 3M56, perhaps 1..3 layers or split bobbin.If you insist on exotic wire, best Litz suppliers are MWS, Rubuadue, etc.Byej

author: wrangler
author_rank: Newbie
timestamp: April 29, 2023, 10:58:07 pm
content: You probably don't need need litz for your flyback--I've been following your threads. That's one topic. It does cost a bit more, but more importantly: it's a pain in the ass to work with and manufacture with. Go build some transformers with litz, then you'll know. Try getting soldering consistent first before you wind.You'll be surprised how high you can actually run current density with boring old wire.Triple insulated... it depends on your application and regulatory compliance. Double and triple insulation wire may be also be preferred techniques by your manufacturer over things like say, sleeves and margin tape. Let your manufacturing process guide you here.

author: Faringdon
author_rank: Super Contributor
timestamp: April 30, 2023, 09:04:50 pm
content: Thanks, ayk, you cant buy enamel coated Litz wire, and you cant buy double insulated litz wire.......the only one you have available to you as "joe bloggs", is triple insulted litz, AKA TEXELZ.Soldering is an issue, and yes it does need little solder thimbles to dip the end in to de-insulate the soldering ends.
Battery type  - Page 1
Forum section: electronics / general

author: mike_mike
author_rank: Super Contributor
timestamp: May 01, 2023, 02:32:26 pm
content: Hi! I would like to know what type of battery can this circuit charge ?https://www.electroschematics.com/dual-mode-battery-charger/I know that on the site is mentioned lead acid battery, but I wanted to know if it is compatible in particular with gel batteries ?

author: David Hess
author_rank: Super Contributor
timestamp: May 01, 2023, 08:59:45 pm
content: Quote from: mike_mike on May 01, 2023, 02:32:26 pmWith the appropriate voltage and current limits, it will work with flooded lead-acid, AGM lead-acid, gel-cell lead-acid, or the various rechargeable lithium chemistries.
High Power Boost Converter Evaluation question - Page 1
Forum section: electronics / general

author: Magnethicc
author_rank: Contributor
timestamp: April 19, 2023, 11:19:20 am
content: Hi Everyone,I have a boost converter:Input = 30V ~ 52VOutput = 96V ~ 117VThe converter contains 4 interleaved boosts converters, each converter have 2 parallel MOSFETs as the switching element and 1 diode as the rectifier.I want to evaluate the MOSFETs operations (Vds, Ids, SOA, losses, etc..) - is it safe to assume that the worst case (in tearms of peak Vds, losses, SOA) of the MOSFETS operation will be at the lowest input, highest output, full load?

author: jonpaul
author_rank: Super Contributor
timestamp: April 22, 2023, 02:47:47 pm
content: no. That is for a linear supply.j

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: April 23, 2023, 03:27:32 pm
content: Quote from: Magnethicc on April 19, 2023, 11:19:20 amthat is correct.

author: wrangler
author_rank: Newbie
timestamp: April 29, 2023, 11:03:29 pm
content: Quote from: Magnethicc on April 19, 2023, 11:19:20 amIt's mixed. Obviously, if you're at low input, you've got a lower Vds, right? Your SOA will probably improve there. But, with the lowest input and the highest output under full load, then it just naturally follows that the switches have the most work to do, right?
CLC filter worse for ripple current - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 27, 2023, 06:48:37 pm
content: Hi,Page 22 shows an CLC mains input filter....AN-70https://www.power.com/sites/default/files/documents/an-70_linkswitch-tn2_design_guilde.pdfIf the two electrolytic caps just got paralleled, and the inductor was put in the AC section, then there would be less overall ripple current stress to those two electrolytic capacitors. This is obvious, and i have a sim to proove it.So why do they use a CLC filter?

author: CosteC
author_rank: Regular Contributor
timestamp: April 27, 2023, 07:11:35 pm
content: This filter not only reduces ripple to SMPS, it also prevents noise from exiting SMPS into mains. Hence its PI construction. I think.Awful half-cycle rectification contraption...

author: Phoenix
author_rank: Frequent Contributor
timestamp: April 28, 2023, 01:44:42 am
content: Put a LISN in your simulation and look at the mains conducted noise.

author: Faringdon
author_rank: Super Contributor
timestamp: April 28, 2023, 05:52:29 am
content: Thanks, i can see the noise conducted by looking at the current, and its smooth without pi filter

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: April 28, 2023, 03:46:15 pm
content: Also keep in mind that several filter topologies in power supplies change their steady state behaviour drastically if the current through them goes to zero.

author: Faringdon
author_rank: Super Contributor
timestamp: April 29, 2023, 10:57:00 am
content: QuoteThanks, though as you know, we dont absolutely need PI construction for this. So why PI.?..why not preserve the input electrolytic caps....we can put filter inductors in the AC section and prevent noise escaping the SMPS.
How do you test a product for Mains Harmonics etc? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 30, 2023, 09:32:43 am
content: Supposing you have a power supply (which supplies a household handheld consumer product) whose load is only ever sudden full_load_to_no_load transients and vice versa…..Full load is 400W.The averaged_out power over some 20 mins would be about 150W.100-265VAC inputFull mains isolation.36 to 42Vout….During its testing for Mains Harmonics (EN61000-3-2) , Conducted EMC , and Radiated EMC, would the PSU be required to be on a constant steady load, or would it be required to be connected to its normal transient load?The transients are eg 10ms ON, 4ms OFF……and other timings.

author: tggzzz
author_rank: Super Contributor
timestamp: April 30, 2023, 09:37:32 am
content: Test the product you are selling - not the components of the product you are sellling.

author: jc101
author_rank: Frequent Contributor
timestamp: April 30, 2023, 09:42:42 am
content: My local test house would say the test configuration should be the normal operational mode of the DUT. This operational mode should be the worst case, so if a device has 2 serial ports, they should both be active etc.If you are testing just this PSU, and it's designed to be used with a household handheld consumer product, it should be tested with such a product. Likewise, testing the household handheld consumer product would require testing with the PSU. If they were being sold together as a single product.

author: Faringdon
author_rank: Super Contributor
timestamp: April 30, 2023, 10:26:55 am
content: Thanks, as you know, PFC stages have a bandwidth of some 8 Hz or so.......so unless the PFC output capacitor bank is very oversized, then the SMPS will not be able to pass Mains Harmonics regulatory testing.....since PFCs simply dont have the bandwidth to provide for transient loads.......i cant see how a product can actually even be tested for Power factor correction, if its load is not steady and constant?
Help advise on most efficient step-up (boost ) product for AC 220 V - Page 1
Forum section: electronics / general

author: abdulbadii
author_rank: Frequent Contributor
timestamp: April 23, 2023, 02:28:35 am
content: One please help advise one of best-buy, the most efficient step-up, ie. boost method, tool product for AC 220 V as the mains sometimes down to as low as 179.5 V ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 23, 2023, 12:59:48 pm
content: Most modern switching supplies are rated to work over the full range of 100-240V. However, such a large voltage drop likely indicates a bad connection somewhere which is a fire hazard.

author: TimFox
author_rank: Super Contributor
timestamp: April 23, 2023, 01:41:52 pm
content: A Variac?This is an AC mains problem.However, I agree that such a large voltage drop is a problem in itself that could prove dangerous.

author: BradC
author_rank: Super Contributor
timestamp: April 23, 2023, 02:22:25 pm
content: Quote from: abdulbadii on April 23, 2023, 02:28:35 amAn APC SmartUPS. They have built-in Boost/Buck using additional windings to provide an autotransformer. If it falls outside of tolerance from there then it switches to battery.

author: jonpaul
author_rank: Super Contributor
timestamp: April 23, 2023, 02:29:08 pm
content: most modern SMPS have a PFC boost at inputs so universal mains 100..265V.Thus no added equipment needed if the device has a modern PFC input stage.Otherwise for a mains booster use a buck boost mains transformers rated for the loadj

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: April 23, 2023, 03:14:54 pm
content: Quote from: abdulbadii on April 23, 2023, 02:28:35 ami assume that you are looking for something that can do AC voltage stablization at consumer end points such as house- or workshop- entry connections. you may want to search for "variac servo stabilizer".

author: bdunham7
author_rank: Super Contributor
timestamp: April 23, 2023, 03:23:41 pm
content: Quote from: abdulbadii on April 23, 2023, 02:28:35 amSo where are you? If your mains are at 179.5V in the US (or Canada) then you need to call someone. The only way I can see that reasonably happening is if you have one leg of an overloaded 208 3-ph service as your '220V'.The problem with your question is that we don't know how much power you are talking about or any other relevant details. What is your nominal mains voltage, or IOW what is it supposed to be? How much does it vary? What is the ampacity of the circuit and how much current does your device (whatever you want to supply boosted power to) draw? And what is that device, exactly?

author: Gregg
author_rank: Super Contributor
timestamp: April 23, 2023, 06:58:01 pm
content: Search for power line conditioners. Simple ones are auto transformers with automatic switching of the various taps. Some are more efficient than others YMMV depending on your exact requirements.
Adjustable LiFePo4 charger with high efficiency - Page 1
Forum section: electronics / general

author: rfspezi
author_rank: Regular Contributor
timestamp: April 21, 2023, 05:59:37 pm
content: I am looking for a cheap, adjustable LiFePo4 charger (230 Vin, 12 or 24 Vout, Icharge up to approx. 10A) with high efficiency.Can anybody recommend a device or a solution?I was thinking of using a cheap laboratory power supply - however i fear the efficiency of these devices is far below 90%?
Innoswitch switching frequency - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 16, 2023, 01:33:36 am
content: HiWhat drives the switching frequency recommendation for innoswitch3-EP seen on pg19 of its datsheet? Is it that the FET turns on very slowly (long time in the linear region) and thus in some cases switching frequency must be very low?...Innoswitvh3-EPhttps://www.power.com/sites/default/files/documents/innoswitch3-ep_family_datasheet.pdfIts just occurring that since the fet and drive are contained in the chip, you have no control over fet gate series resistance etc.....and im beginning to wonder if its just better to use a standard controller with external fet, rather than the innoswitch.

author: temperance
author_rank: Super Contributor
timestamp: April 17, 2023, 11:49:59 pm
content: 1. Do you understand you're own question?2. Did you ever try to "imagine" what would happen when turning on the switch that slow.3. You are mixing switching freq. and MOSFET turn on time. They have noting to do with each other. (in this case)4. If you ask this question it means you could do some research about QR flyback converter.A starting point:https://www.ti.com/seclit/ml/slup302/slup302.pdfLast but not least: contact the Chinese if in doubt. As you know, they do know how those things work because someone shared the secret and sacred knowledge with them.

author: Faringdon
author_rank: Super Contributor
timestamp: April 18, 2023, 05:59:56 am
content: QuoteThanks, as you know, if the turn on time is long ish, but the switching frequency is low...then this kind of helps, as the lower switching frequency lowers the switching loss.As you know, slow drain transistion time helps common mode emc.

author: temperance
author_rank: Super Contributor
timestamp: April 18, 2023, 09:47:49 am
content: I'm glad to know that a lot of SMPS's are being developed in China. Because if you would be developing them, the world will heat up even faster.

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: April 18, 2023, 11:12:04 pm
content: My interpretation is that the characteristics of the internal FET switch will vary based on the size of the particular device within the family, and so they have done the math on what the ideal frequency is in order to compromise between the different types of losses present. For example there is a tradeoff between Rds(on) and gate-drive losses. A larger FET will have lower Rds(on), but that comes at the cost of higher gate capacitances and thus higher gate-drive losses which will worsen as frequency increases.https://www.ti.com/lit/an/slyt664/slyt664.pdf?ts=1681803346547&ref_url=https%253A%252F%252Fwww.google.com%252F
That's what I call ... power ! - Page 1
Forum section: electronics / general

author: Zfrenchy
author_rank: Contributor
timestamp: April 10, 2023, 04:56:55 am
content: 20kV AC to 70kA DC rectifier !https://youtu.be/cvsj0nqHwic

author: f4eru
author_rank: Super Contributor
timestamp: April 10, 2023, 07:16:17 pm
content: a pity this will all be used only for a few minutes for a hopeless cause over it's lifetime.

author: jonpaul
author_rank: Super Contributor
timestamp: April 10, 2023, 07:40:23 pm
content: Like other fusion projects, ITER is mostly a political greenwashing, as it will always be 30 years more to be practical power source.Here is a working 500 kV DC transmission terminal hall...An optically isolated cycloconverter to 3 phase - 2KA continuous 24/7 serviceThis is power electronics rather than just an electric substation.A Technicien is barely visible in lower rightEnjoy!Jon

author: Gyro
author_rank: Super Contributor
timestamp: April 10, 2023, 08:23:05 pm
content: I wouldn't want to be responsible for maintaining the lights!