hybridfree/eevblog-posts huggingface dataset:
Seeking Square Law torroid  core? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: September 05, 2021, 10:58:43 am
content: Hi,We are seeking a "square law" ferrite torroid to use as a fluxgate sensor for imbalance current detection. For 50Hz mains electricity.No manufacturer seems to make these.I tried Far-rite, Mag-inc, Ferroxcube and TDK, but no joy. Plenty of high permeability (eg 5000), but no "square law".We need OD= >35mm, ID = >15mmDo you know of any?

author: David Hess
author_rank: Super Contributor
timestamp: September 05, 2021, 05:23:05 pm
content: Isn't that the same thing as "square loop" cores used for magnetic amplifiers?

author: Faringdon
author_rank: Super Contributor
timestamp: September 05, 2021, 08:41:55 pm
content: Thanks, yes square loop cores, thats it.

author: David Hess
author_rank: Super Contributor
timestamp: September 05, 2021, 11:50:32 pm
content: That being the case, a search for "square loop ferrite" on Google or "MAGAMP" on Mouser turns up lots of results.

author: jonpaul
author_rank: Super Contributor
timestamp: September 06, 2021, 02:15:22 am
content: Bonjour Faringdon, crazy busy, so just noticed your post now.A "square law" ferrite has no meaning to me. Square loop is better but you will not see it in Ferrite, only steel. And its used in magnetic amplifiers but perhaps not flux gate.All magnetic materials are nonlinear B-H but the curves have hysteresis, saturation, etc.Most Fluxgate current sense applications use tapewound cores of high perm grain oriented steel, the exotic materials like Amorphous are super costly and unneeded here.If you can better define the entire circuit/system and spec linearity, peak current and response time we can respond more cogently.The best source of tapewound cores was Arnold magnetics and Magnetic materials in the USA but that was in 1970s..1990s.Suggest to study the many fine books, papers and references on Flux Gate current sensors before you reinvent the wheel.Bon Chance,Jon

author: Faringdon
author_rank: Super Contributor
timestamp: September 06, 2021, 06:11:39 am
content: Hi,Thanks, Merci,Bon Matin, Its 32Arms mains distribution box.Weeed to detect >30mA imbalance current between line and neutral.We also need to detect any DC current flowing.We need to know when DC >6mA so we can turn off.

author: jonpaul
author_rank: Super Contributor
timestamp: September 06, 2021, 07:44:15 am
content: Faringdon:The tapewound toroids are availabe in a variety of tape thickness, 0.5 mil, 1/2/3/5/6 etc.For the operating frequency you can slect a tapewound with appropriate losses.For the "square loop" it does not exist in ferrite, they are all rather soft.BTL developed many special material in 1930s ..1950 for telecomm use, some were close to square.BUT no needed in your application and super expensive materials. I vaguely recall SupermenDur, but perhaps not,Enjoy,JonPS: Many off the shelf solutions exist try the current sensor firms searchinbg just "current sensors" I found dozens of firms.
Potentiality new wireless power transfer for Eev to bust  ! - Page 1
Forum section: electronics / general

author: Oy1r
author_rank: Contributor
timestamp: September 04, 2021, 04:57:31 pm
content: Room-scale magnetoquasistatic wireless power transfer using a cavity-based multimode resonatorhttps://www.nature.com/articles/s41928-021-00636-3Something to dissect and bust perhaps or invest in ? hihi.Good on you mate.Dtio, Tiap.

author: Marco
author_rank: Super Contributor
timestamp: September 05, 2021, 03:45:11 am
content: Disney did it already.https://www.iflscience.com/technology/disney-researchers-make-wireless-power-transfer-breakthrough/

author: Gyro
author_rank: Super Contributor
timestamp: September 05, 2021, 10:49:45 am
content: In these days of looming environmental disaster, an energy transfer efficiency of 37% (or 40 - 95% if you actually believe Disney!) puts this firmly in 'Dodgy Technology' territory.From the Disney photo, it doesn't look very domestically acceptable either - unless you happen to be a pole dancer with a death wish.I find the idea of injecting 1.32MHz at a level of 1.9kW into a living space about as attractive as a hole in the head.It seems like, the more we make minor achievements in improving the greenness of out power generation, there seem to be an ever increasing number of dickheads, hell bent on a quest for the highest energy wastage. I thought wireless phone chargers were bad, but....

author: Marco
author_rank: Super Contributor
timestamp: September 05, 2021, 11:44:20 am
content: For Disney it was just a proof of concept, probably some engineers given a little time to screw around as a sort of sabbatical. I suspect that with the faraday cage, you could set up the standing wave with large coils in one of the ceiling/floor/wall too (and the cage should probably have ferrite tiles on top of the steel).It's not the power you have to be concerned about, it's the field strength. Humans don't couple very well ... pretty much all the power is going to go into the walls and stuff which can actually resonate at the frequency (like a receiving coil). If it puts a couple mW in an entire human (or some steel implants) it's not going to do anything, we're a big bag of water ... it takes a lot of power to heat any part of us up.PS. actually not coils, coils are expensive. I assume the new paper uses something like a 2 layer Faraday cage, with the ceiling/floor/wall surfaces of the inner cage isolated from each other and voltage driven. In that case the system could be constructed simply with a relatively thin material on a roll you apply to all the room surfaces. That might actually be somewhat practical for small loads.

author: Gyro
author_rank: Super Contributor
timestamp: September 05, 2021, 01:04:08 pm
content: ... and the transfer efficiency?

author: Marco
author_rank: Super Contributor
timestamp: September 05, 2021, 01:15:59 pm
content: Awful, but it's not like the efficiency of a phone charger matters in the big scheme of things.Still, it's never going to find any adoption. Too easy to make scare stories for "you're sitting in a giant microwave!!!!".
SMPS' bridge diode rectifier before the transformer ? - Page 1
Forum section: electronics / general

author: abdulbadii
author_rank: Frequent Contributor
timestamp: September 03, 2021, 01:53:13 am
content: Why is SMPS' bridge diode rectifier before the transformer which won't/shouldn't work having a DC input ?Can anyone crystal clearly but succinctly explain how or which is the processes of DC step down ?

author: bob91343
author_rank: Super Contributor
timestamp: September 03, 2021, 02:20:44 am
content: The transformer is part of an oscillator, thus providing ac for the transformer. The transformer operates at a much higher frequency than the power line and thus can be much smaller than one for low frequency.

author: james_s
author_rank: Super Contributor
timestamp: September 03, 2021, 04:57:19 am
content: By definition a SMPS has to work like this, have you looked at a block diagram? The incoming AC is rectified and filtered into a DC rail. It is then chopped (switched) by one or more transistors, turning it into high frequency AC enabling a much smaller and lighter transformer to be used than would be required at mains frequency. That switching is the reason it is called a "Switch Mode Power Supply" in the first place. The high frequency AC is then rectified back into DC and filtered to become the output. The output voltage is normally monitored and used in a feedback loop to control the duty cycle of the switching part, giving you the regulated output.There are many SMPS's that run off DC instead, these are typically called "DC-DC converters" but they are just a specific type of SMPS.
bms connections - Page 1
Forum section: electronics / general

author: m3vuv
author_rank: Super Contributor
timestamp: September 02, 2021, 08:28:38 am
content: by m3vuv » Sep 01 2021 3:30pmHi all,i have a new 13s smart bms,what is the correct sequence to connect it to the pack,i assume battery minus first followed by the balance wires then the load?,just dont want to let the smoke out of it,tia paul m3vuv.Just another question,this aliexpress smart bms came with zero paperwork,it has a bt modual connected to it,does that mean the bt is always pulling juice from the battery pack?,or does it only turn on when i pull a load or charge the pack?,this is what i had delivered( its the 60 amp version)https://www.aliexpress.com/item/3300076 ... 4c4dAranMIthis is what i got from there site,poorly translated and as clear as mud!tia
Bootstrap voltage circuit - Page 1
Forum section: electronics / general

author: snoop33
author_rank: Contributor
timestamp: August 31, 2021, 05:44:35 pm
content: Requirement, to offer 4-4.4v from something above this level up to 100v at 6mA, with as little dropout as possible, minimal components and cost. The 6mA will boot a CPU which starts a buck which raises the voltage to 5V so at that point the bootstrap isn't used.I've managed two alternatives, one more expensive than the other. The only way to improve that I can find is to lower the 56k resistor considerably but I only have room for a 0402.First went with a low voltage zener (4.7v) but the knee makes it hopeless, then went with the LM4040 which is far better but still not great and found I can equal it using a 6.8v zener and LED.(not shown) it needs 9v to make the ~4.4v regulation.

author: snoop33
author_rank: Contributor
timestamp: August 31, 2021, 07:02:41 pm
content: Voltage series regulator looks better in theory, but that 3v zener, it has the current from the 56k and the 4.7k and I doubt it's enough to keep it in regulation in reality. Perhaps I'm wrong though?

author: Slh
author_rank: Regular Contributor
timestamp: August 31, 2021, 09:59:47 pm
content: You might have issues with the variation in Vbe with temperature, manufacturing tolerances etc. You might struggle to get +/-200mV with those simple circuits.If you can take a 12V drop then a microchip LR8 looks ideal (and, amazingly appears to be in stock which is rather unusual these days...)

author: snoop33
author_rank: Contributor
timestamp: September 01, 2021, 07:30:19 am
content: Unfortunately not, I'm really after 2v LDO, the first two circuits require about 9V to regulate to about half that which is not ideal. The third is better but experience tells me LTSpice isn't modelling the knee of the zener and I doubt it'll keep up regulation. I could try a LM4040-3.0 instead of the zener though.

author: Slh
author_rank: Regular Contributor
timestamp: September 01, 2021, 10:15:56 pm
content: Lm4040 looks like it needs at least 60uA for good accuracy. I'd be tempted to do the second regulator with the LM4040 and a 13k resistor. You've still got to contend with the Vbe variation but you don't have to worry about the zener voltage changing.Alternatively I think you could look at using PNP BJTs with the NPNs to cancel the NPN Vbe variation. Can't remember the details but I think the Art of Electronics has some tips.
Battery powered 3 phase power for edm machine.  - Page 1
Forum section: electronics / general

author: chrismholt
author_rank: Newbie
timestamp: August 29, 2021, 11:31:01 pm
content: I would like to put an EDM machine that needs three phase power in my garage. I dont have high current service or three phase power. Is there a solution that might run a three phase machine off of a battery? I only plan to use the machine for 20min at a time a few times a day at most.

author: BrokenYugo
author_rank: Super Contributor
timestamp: August 29, 2021, 11:51:51 pm
content: Power requirement?I guess you could feed the DC bus of a VFD somehow, but running said VFD from the nearest 240V stove or dryer plug (derate something like 50% for single phase input) would probably be a lot cheaper and easier. Or just use this as an excuse to install a 50A welder plug in the garage.

author: chrismholt
author_rank: Newbie
timestamp: August 31, 2021, 09:21:38 pm
content: Note taken. I will look for other solutions before a battery.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 31, 2021, 11:22:51 pm
content: get a couple hp 3 phase motor and build yourself a rotary phase converter, run it off a dryer outlet. Simple, cheap, effective.Depends on how much power your edm draws, but single machines will generally not be a problem.I run all my machines using a 7hp phase converter with a 30A 240 feed. It will run most anything up to 5hp before tripping the breaker

author: BradC
author_rank: Super Contributor
timestamp: September 01, 2021, 12:24:13 am
content: Quote from: chrismholt on August 29, 2021, 11:31:01 pmThe important question is, why does it need 3 phase power?One of my neighbours mills "needs" 3 phase, but at the end of the day it's fed into a rectifier to create 415V DC. Does it have an induction motor that needs accurate 3 phase or is it just set up that way because most placed it'd normally be found have 3 phase?You might be able to give it what it really needs rather than what is implied when you say "3 phase".

author: langwadt
author_rank: Super Contributor
timestamp: September 01, 2021, 12:42:38 am
content: Quote from: BradC on September 01, 2021, 12:24:13 amyou need much less capacitance to make DC from three phase than single phase, because it has much less ripple after the rectifierVFD s that can run from both usually need to be derated quite a bit when run from a single phase
Lowering the R parallel to the last C outpu - Page 1
Forum section: electronics / general

author: abdulbadii
author_rank: Frequent Contributor
timestamp: September 11, 2021, 01:54:11 am
content: There're 12 Volt 5-6.5 A SMPSes availabe in market but the need is the lower 6-9 V of such rating, so can we just lower the R parallel to the last C on output or not (riskier to safety)?

author: bob91343
author_rank: Super Contributor
timestamp: September 11, 2021, 02:10:25 am
content: It's not that simple. Lower output voltage may compromise performance at high input voltage. Current capability may change. It all depends on the specific design.
AC Generator -> PFC and MPPT combined - Page 1
Forum section: electronics / general

author: snoop33
author_rank: Contributor
timestamp: August 18, 2021, 08:36:23 am
content: Hi,I have some confusion around how to integrate these two techniques and have drawn a diagram.1. Assuming an inductive power source which is fixed current and voltage tracks frequency (under no load), but which due to high internal resistance saturates easily hence MPPT is a win. Generally it will operate at 6v minimum and will saturate to 20v peak under load (20v*0.5A = 10W). I can assume there is always a load (4) so >20v seen at the supply shouldn't happen (a mosfet relay will turn the system off when (4) is full).2. PFC either by switched in capacitors or APFC buck/boost chip provides a different DC voltage for a given frequency. I don't know if this voltage can be determined without knowing the load which is the first question, because if the load changes the PFC will generate a different voltage I think. Since the input voltage under load won't exceed >20v a boost will work here. Unless I can find a APFC chip that works at these low voltage levels I may have to roll my own.Assuming PFC has reduced supply LCR impedance to R impedance by P.F of 1.0 (for theory). Impedance can be calculated by series/parallel resistance of the generator and frequency. Presenting an equivalent resistance as a load will equal MPPT.3. The resistance is simulated by a buck in CCM mode (by setting duty).4. The super-cap is large enough to sink anything (3) provides.How's my understanding?!

author: Faringdon
author_rank: Super Contributor
timestamp: August 30, 2021, 02:49:59 pm
content: Hi, it sounds like you are on to something interesting. From "MPPT" i take it there is a solar array in here somewhere? So you have a 5V load that you want to power from either an AC generator, or from a solar array?
Auto reset Li-ion battery protection for holders? - Page 1
Forum section: electronics / general

author: DaveC1964
author_rank: Newbie
timestamp: August 26, 2021, 03:27:11 am
content: So we have those Li-ion PCBs out there which everyone has seen that are meant to be soldered to a battery such as an 18650. I have an application where I want a socketed 18650 to be protected no matter what battery is used. I want to put the protection PCB on the socket/holder not the battery so that any non protected battery used in the holder will be protected from over charge, or over drain etc. I tried just soldering one to the holder but sometimes when the cell is put in that act causes the PCB to trigger and lock out. The only way to make it work is to remove and insert the battery a few times until it works. That is a hassle and not practical. Is there a protection PCB out there that will auto reset so that when the battery is placed in the socket it will always work? I see a bunch of PCBs out there but don't know what to look for, Thanks.
LM5030: Startup issue due to output capacitor inrush current - Page 1
Forum section: electronics / general

author: Arb32
author_rank: Newbie
timestamp: August 22, 2021, 07:04:11 am
content: Hi, I was designing dc-dc converter using LM5030 , the output specifications areOutput 1: 13V, 4.9AOutput 2: 13V, 3.8 Athe primary input voltage is 74V and the estimated primary continuous current is 4.3Aso for overcurrent protection is was going to set the current sense resistor connected to current sense pin to stop the ic for current above 5 A on the primary sideThe issue is as per the simulation the inrush current on the output capacitor was 22 A so the corresponding increase in current demand would be reflected on the primary side which would exceed the set current limit hence would stop the ic and hence the converter wouldn't work at allAny solution to this?

author: bob91343
author_rank: Super Contributor
timestamp: August 22, 2021, 07:38:35 pm
content: Put in a delay circuit to prevent the overcurrent sensor from tripping until enough time has passed. Or slow it down.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: August 23, 2021, 04:23:06 am
content: This is current mode control and the controller should limit the primary current. Did you implement the control function of the IC in your simulation?The chip has soft start up control according to the data sheet.https://www.ti.com/lit/ds/symlink/lm5030.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1629692448856&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Flm5030
can I put 3 individual USB chargers in series to charge the series battery pack? - Page 1
Forum section: electronics / general

author: ErwinsCat
author_rank: Regular Contributor
timestamp: October 09, 2021, 09:03:19 am
content: I'm wondering if it is possible to use 3 of these battery chargers (3xTP4056)https://www.ebay.com.au/itm/402351347534?var=672349851255to charge a pack of batteries like a laptop battery pack.

author: ledtester
author_rank: Super Contributor
timestamp: October 09, 2021, 11:35:05 am
content: Your schematic is confusing or is wrong because a TP4056 module has separate inputs for the battery connection, power output and charging supply.You can use TP4056 modules in series, but each TP4056 will need its own isolated power supply. This has been done before, e.g.:https://www.eevblog.com/forum/projects/multi-cell-lithium-charger-from-a-single-5v-supply/msg1454259/#msg1454259and here's a schematic of the idea:https://electronics.stackexchange.com/a/274957/95488

author: ErwinsCat
author_rank: Regular Contributor
timestamp: October 09, 2021, 02:28:13 pm
content: Thank you for your reply, I did not realize modules have a common ground now I understand the issue with my idea. thanks again I'm happy I didn't tried my idea I think without a floating power supply, technically I would shorting 2 bottom batteries.
Large iron common mode chokes to equalise currents? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 19, 2021, 11:39:02 am
content: Hi,Please could you say if this setup, with large iron common mode chokes, will equalise the live and neutral currents to within 30mA of each other?https://ibb.co/5T3x6p4(The currents must be equal or else the RCD in the UUT trips.)(It comes to me from the old "Current sucking transformers" used in Germany in the old days to equalise electric railway go and return currents, so that return current did not flow in earth and cause corrosion to pipes etc)

author: uer166
author_rank: Super Contributor
timestamp: August 19, 2021, 05:18:05 pm
content: Instead of doing a synthetic test-bench with current sources that create shorted turns around UUT, use a real 16A/240V load.

author: Faringdon
author_rank: Super Contributor
timestamp: August 19, 2021, 06:28:08 pm
content: Thanks, but it wastes too much power, as we have multipel production lines.

author: Gregg
author_rank: Super Contributor
timestamp: August 19, 2021, 09:04:11 pm
content: It appears that Faringdon fell into another rabbit hole while looking for his alter ego opampsmoker who is running amok in a forest of treez. While his brain is running in circles trying to find himself; his schematics have currents running in similar circles around a fantasy device under test. Complex solutions for simple to non-existent problems abound in his fairy tale world.These dizzying quests should be written into more cohesive fairy tales and then presented to whoever in the BBC writes whole mystery and spy series programs based on children’s fairy tales.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 19, 2021, 10:37:28 pm
content: How about a transformer with something like a 1:1.05 turn ratio to move power from one side to the other, with a relatively small variable resistance to fine tune the current?I suppose reactive loads could be another idea, just beware the inrush current with a capacitive load and the flyback voltage of an inductive load.
Overcurrent rating selection - Page 1
Forum section: electronics / general

author: Arb32
author_rank: Newbie
timestamp: August 17, 2021, 06:29:36 am
content: Hi,I was designing a dc dc converter and was inserting a fuse at its input side for overcurrent protection,saw various parameters for fuse selection, but had one basic doubt, how to determine the current limit at which the fuse should tripThe continuous primary current rating is 4.9A

author: David Hess
author_rank: Super Contributor
timestamp: August 17, 2021, 08:15:17 pm
content: It depends more on what the source can supply and a short will allow and less on the maximum load current. A fuse is a safety device and not really a protection device. This means that the fusing current needs to be low enough that a short will trigger the fuse.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 18, 2021, 02:05:20 pm
content: Fuse protects against fire only and is sized depending on conductor area / width, insulation material temperature rating, etc.Fuse is not and cannot be used for overcurrent protection of DC/DC converter. But all modern DC/DC controllers implement current limiting or protection, refer to their datasheets.Classical fuse on the input is still a good addition in case the DC/DC circuit blows up short circuit, to protect against fire, especially when the upstream supply is not protected or its protection is at seriously higher current (for example, a battery pack).
RC filter design connected between current sense resistor and current sense pin - Page 1
Forum section: electronics / general

author: Arb32
author_rank: Newbie
timestamp: August 06, 2021, 01:23:13 pm
content: Hi,I wanted to design a RC filter connected between the current sense resistor and current sense pin for eliminating noises, I have gone through many articles and datasheet of lm5030 but didn't find how to select the values of R and C, I have attached a example here with another ic,here r19 is current sense resistor ,r22 and c13 form the rc filter,also attaching datasheet of ic

author: Faringdon
author_rank: Super Contributor
timestamp: August 07, 2021, 12:02:21 pm
content: filter as hard as you can, without loosing the shape and magnitude of the sense signal........just get rid of the leading edge spike....use the simulator to help you......give me spec and i will send you sim....then you can experiemtn with rc filter values.Its usually anywhere from 100p/100R to 1n/1k

author: Arb32
author_rank: Newbie
timestamp: August 17, 2021, 06:26:08 am
content: Thanks will try this soltion,if unable to do will send thesimulation file here

author: Faringdon
author_rank: Super Contributor
timestamp: August 17, 2021, 06:32:29 pm
content: yes , here is sim in ltspice of push pullYou can experiment with sense filterI think i sent it to you before but i cant remember, so i send again here.
Power issue troubleshooting  - Page 1
Forum section: electronics / general

author: dEEz
author_rank: Newbie
timestamp: August 17, 2021, 02:48:22 pm
content: I have got a board built up of a DC filter and a few isolated switch mode DC to DC converters. This board powers a number of devices downstream and the board itself is powered by a lab power supply. One of the devices connected did not boot up properly when letting the full load hit all at once, I unplugged everything but that device and powered it up by itself and it boots up fine. Probably an inrush current issue. The thing I don’t understand is when instead of unplugging every other device I put switches on their supply line, my issue returns. What is the difference between having the rest of the load unplugged and on a switch?
Home-scale thermal energy storage - Page 1
Forum section: electronics / general

author: Circuitsoft
author_rank: Newbie
timestamp: August 10, 2021, 05:38:33 pm
content: This video is a lot more interesting that it may initially appear. Especially, the idea that utilities could tweak thermostat settings to take the best advantage of, predictable (weather), renewable energy sources, reducing the need for grid-scale energy storage.He also touches on other thermal energy storage systems like ice blocks. Kinda makes me wonder about having a large, insulated, water tank in the house that gets heated and cooled as necessary, then all other heat and cooling in the house can run against it via heat pumps. Furthermore, having a heat-pump water heater and an ice block, you could run refrigeration off the ice block, and freezers off heat pumps to the ice block. By re-freezing the ice block when the utility has cheaper power available, the need for peaking power could be severely minimized, if not outright eliminated.

author: f4eru
author_rank: Super Contributor
timestamp: August 11, 2021, 09:34:31 pm
content: There's a huge difference of scale between a daily storage and a seasonal storage.I have a 2-day thermal storage (in water)

author: Circuitsoft
author_rank: Newbie
timestamp: August 16, 2021, 07:04:20 pm
content: Yes, but two day storage is plenty to make use of varying energy availability. If you had a heat pump that could heat/cool your water tank from the outside, and the power company could control the speed of that heat pump, that would drastically reduce your usage of peaking power (almost exclusively natural gas power), allowing the utility to provide more renewable energy, and rely less on grid-scale electrical storage.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 17, 2021, 01:20:58 am
content: I have plans to build such an ice storage device for air conditioning, the main difficulty is getting a good dynamic range in order to adapt to varying solar production. All of the high dynamic range BLDC A/C compressors I have come across have some proprietary control system that's difficult to repurpose. Most promising seems to be a switchable displacement compressor giving about a 3:1 dynamic range on top of the 2:1 or so that can be achieved using a VFD controlling a standard compressor. What's left over will have to be handled using batteries.

author: Nauris
author_rank: Regular Contributor
timestamp: August 17, 2021, 09:53:18 am
content: Quote from: NiHaoMike on August 17, 2021, 01:20:58 amRegular a/c inverter compressor have good dynamic range I took photo of one:45...321 Hz that is 7:1 range. They can be run with standard vfd supporting permanent magnet variable reluctance motors for example Yaskawa V1000- series. I had one little bigger than this compressor running last winter on such setup.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 17, 2021, 09:59:54 am
content: This comany makes thermal storage units using phase-change materials ( similar to those hand warming packs)https://sunamp.com/
Charger Delta Electronics ESR-48/40A Voltage and Current Adjustments - Page 1
Forum section: electronics / general

author: GA
author_rank: Newbie
timestamp: December 31, 2019, 11:22:29 am
content: Does anybody know how to change the output voltage and limit the output current in the Delta Electronics ESR-48/40AE charger? The following web pagesthis oneand thenext onehave pinouts for two other Delta chargers that seem to match my charger. I believe they all usePMBUSprotocol, but I have no experience with is whatsoever. Can I use thisCP2112 Debug Board USB to SMBus I2C Communication Modulefrom AliExpress to change the charger's parameters and how?I'm linking the pinout images directly here:Delta ESR-48V/56AC 54V(54V~59V) 50ADelta ESR-48/30G C 54V(43V~58V) 32.22AI have attached pictures of my charger and a two page fact sheet PDF.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 31, 2019, 01:47:01 pm
content: You have to use the ADJ pin to change the output voltage and then the output current will change accordingly. Most power supplies do not allow the user to change the current limit.

author: GA
author_rank: Newbie
timestamp: January 02, 2020, 08:00:42 am
content: Do you by any chance know how to use the ADJ pin to change the output voltage? I believe there should be a way to set the current limit as well. I have another chargerEaton APR-48where I can easily change the output voltage AND the current limit separately by changing few bytes in the EEPROM.

author: letuananh122
author_rank: Newbie
timestamp: August 17, 2021, 03:38:56 am
content: I have the picture circuit control of ESR-48/50 here, hope it helps you.

author: letuananh122
author_rank: Newbie
timestamp: August 17, 2021, 03:48:27 am
content: More detailed images of the ESR-48/50A, here.
locatin sw for a smart bms - Page 1
Forum section: electronics / general

author: m3vuv
author_rank: Super Contributor
timestamp: August 14, 2021, 10:28:18 am
content: hi all i brouhjt one of these months agohttps://shopee.ph/MGOD-BMS-13S-48V-20A-Li-Ion-Lipolymer-Battery-37V-PCB-with-Balance-Supports-Ebike-Escooter-i.375038878.9586642623,cantfind the pc sw for it,any idea where to get it,i lost the store addy wgere i brought it from,i have the phone app but its horrid,i need the pc program to set it up,mine is for a 13s lithium ion with uart and bt,cheers in advance.ps i have the 20 amp model.
Torroid CT for measuring leakage current in EV charger? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 12, 2021, 07:20:33 pm
content: Hi,We need to measure the difference between live and neutral currrents in a 16Arms EV Wall box. (difference must be no more than 30mA)As such, do you agree, we should just pass the conductors through a Torroid CT and measure the output?....ie, it will give the common mode current as output.The thing is, do you agree that using the ZCT409 Torroid for this woudl be totally wrong?..ZCT409 torroid CT...ctzentar.com/zero-phase-current-transformer-for-leakage-current-detection-zct409_p28.htmlOur current is only 16Arms.......so we are seriously sacrificing resolution by using this torroid (ZCT409), which is rated to 225A...would you agree with this?Also, the inner diameter is 24mm......and our live and neutral conductors are each only 3mm diameter....as such, they barely fill this torroid. Would you agree that really the inner diameter should be just big enough to fit on the conductors that go through the torroid ring?So do you agree we have chosen totally the wrong torroid?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 12, 2021, 07:56:22 pm
content: Assuming this is for the UK market, You need to be able to measure DC leakage current as well as AC, so need to use something like a hall-effect or fluxgate based current sensor.For example :http://www.magtronworld.com/datasheet/zb_users/upload/2017/11/201711151510713677614896.pdf..and why would anyone want a 16A wllbox when most current cars have a 32A onboard charger?

author: uer166
author_rank: Super Contributor
timestamp: August 12, 2021, 08:13:33 pm
content: Oh jeez trees. I would suggest you give up now, the earlier the better. Designing a compliant EVSE takes a team ofactually competentengineers over a year. I had to read maybe 8 different standards over and over to even begin the designs, and you apparently can't even afford (or most likely unwilling to read) those standards. The certification, testing, and validation costs alone are in the multi-$100k even if you're being scrappy.

author: uer166
author_rank: Super Contributor
timestamp: August 12, 2021, 08:18:06 pm
content: On-topic reply: in EU market you're supposed to measure and act on DC leakageonlyper IEC-62955, in combination with an upstream type-A RCCB. In fact, it explicitly disallows tripping on AC leakage, so you need to filter the AC part out if designing your own sensor. Furthermore, there are very specific requirements on the relay or disconnect switch that needs to be used for this, you can't just use any old relay, and most designs in the market are not compliant and would fail a multitude of tests. Of course, few give a crap when they self-certify.Get and read the damn standards. If you can't afford them you can't afford to design anything anyway.
EV wall boxes more susceptible to mains transients? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 07, 2021, 02:09:13 pm
content: Hi,My Rolec EV charger wall box has stopped working.....https://www.rolecserv.com/home-charginghttps://3814f048-6c69-488c-9f3e-e8df0a79bfd4.filesusr.com/ugd/1667b4_c12fc3582f844b2fab75c4ca72218b7a.pdfIt charges at 3.6kW.Because it uses so much current (16A), it is fed from its own breaker. The other electrical devices used by the house are fed from their own breaker, and their connection points to the mains are much nearer to each other, than to the EV wall box. As such, the EV wall box is more susceptible to mains transients......since there isnt so much transient quenching assistance from the other electrical devices in the house...because they are "distant" from the EV wall box in that there is greater mains wiring inductance from them to the EV wall box.This strikes me as being a big potential problem for EV wall boxes?....ie, they get hit harder by mains transients, due to less nearby devices near them to cooperatively quench the transient?Do you agree with this?

author: Gyro
author_rank: Super Contributor
timestamp: August 08, 2021, 10:22:13 am
content: No I probably don't agree, but from watching several electricians videos, it appears that those Rolec chargers are quite prone to RCD failures.If you're worried about mains transients then just have an 18th Edition SPD fitted to the consumer unit.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 08, 2021, 10:30:11 am
content: Quote from: Faringdon on August 07, 2021, 02:09:13 pmNo reason to think they are more susceptible to transients than any other electronics. Heat related issues are far more common. Rolec's RCDs are notorious for burnt neutral connections, though more common at 32A.Athough Rolec are pretty crap, they do have the advantage of being modular, so faulty parts can be easily replaced.Viridian make soem DIN-rail mounted EVSE cahrge controllershttps://viridianev.co.uk/products

author: David Hess
author_rank: Super Contributor
timestamp: August 08, 2021, 04:45:49 pm
content: I would expect vehicle chargers to be more susceptible because they are high power and complex compared to other typical high power loads like ovens and compressor motors. The same goes for large grid-tie inverters.To make up for that I expect them to be well designed so that external factors like the distance to other loads is irrelevant.

author: Neilm
author_rank: Super Contributor
timestamp: August 09, 2021, 06:10:44 pm
content: Quote from: David Hess on August 08, 2021, 04:45:49 pmThe charger in question is nothing more complex than a relay with some control circuit. Rolec early chargers were know to fail a lot due to the RCD. I don't know if the smart chargers they have been installing for the last few years suffer similar issues as they don't have RCDs in them. A separate RCD is required
Testing an R&D Circuit:  Step Up Transformer to Step Down Transformer - Page 1
Forum section: electronics / general

author: jbf
author_rank: Contributor
timestamp: August 10, 2021, 11:35:49 pm
content: Hi all,I am a brand new user here but have been a lurker for a while.Overview:I am working on a custom R&D MCU controlled dimmer circuit for an art installation that will be installed in Europe on a 220v mains that requires a step-down transformer to run on 110v.The problem:I am located in the U.S. and need to replicate a 220v mains so that I can test the step-down transformer connected to the lighting circuit. This means I need to possibly step-up 110v to 220v and then back down to 110v to test the circuit to ensure the transformers dont cause any issues with operation.The Big Question:Is this safe to use two step up/down transformers in series or are there safety concerns I should be aware of?So U.S. 110v->STEP-UP E.U. 220v->STEP-DOWN U.S. 110v (to test dimmer circuit operation on stepped-down 110v).The lighting circuit only pulls about 110v @ 0.250mA on mains side.Can anyone provide any thoughts or experience on this matter? Thanks so much everyone!

author: bob91343
author_rank: Super Contributor
timestamp: August 11, 2021, 03:44:28 pm
content: I don't see any problem. It should work okay.

author: f4eru
author_rank: Super Contributor
timestamp: August 11, 2021, 09:26:00 pm
content: hmmWhy not test on your home available 240V ? Why not use universal PSUs ?if you want to text your strange setup, be sure to ground the the 240V on 1 side to replicate exactly.

author: David Hess
author_rank: Super Contributor
timestamp: August 11, 2021, 11:57:54 pm
content: Quote from: jbf on August 10, 2021, 11:35:49 pmYes, it is safe.

author: DannyG
author_rank: Newbie
timestamp: August 12, 2021, 12:13:37 am
content: Well if you go that route of the transformers in series, your going to have 60 Hz going to your circuit when in EU its going to be 50 Hz.For incandescent and fluorescent bulbs the frequency difference shouldn't cause a problem. However, with an LED bulb you might (a very soft might) have an issue because of the electronics in a LED bulb. Ultimately I think your going to be good but you will have a different frequency.
Making a 16Arms, 50Hz, AC since source - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 02, 2021, 06:47:57 pm
content: Hi,We are making a device which switches up to 16A rms in the 240VAC mains into a device. It also needs to measure the 16A. We measure it with a Current transformer in mains live.When we test the equipment, we currently load it up with a 16A load, so that we can see that it measures it properly. -But this means us dissipating 3.8kW in a dummy load during production test......not good.Therefore, we wish to simply synthesize a 16Arms sine wave and shovel it through the current transformer, of course doing this while the live conductor around which the current transformer torroid sits is energized....it needs to be in phase with the mains voltage.....We believe we can do this using a kind_of Class D amplifier stage with a 60V isolated DC input power supply as attached. it feeds into a 30V battery, but of course, there is no overall load in this as it receives AC current.What do you think of this?By the way, the control loop hasnt yet been completed in the attached.(LTspice sim and pdf schem attached)

author: capt bullshot
author_rank: Super Contributor
timestamp: August 02, 2021, 07:05:16 pm
content: What is the required accuracy of phase and amplitude?A very simple, but not accurate way would be using a variac and a transformer (with 16A and maybe 5V secondary), secondary shorted through your CT. Somewhat more controllable would be the transformer and an audio amplifier.A very expensive and accurate way would be using a Fluke 5500a (or similar) calibrator. The 5500A can do up to 11Arms, and surely doesn't like connecting it's output to mains live, but can supply e.g. 230Vrms at the same time as 11Arms, so with some modification of the test setup this could do the job.

author: Faringdon
author_rank: Super Contributor
timestamp: August 02, 2021, 08:38:52 pm
content: Thanks, but i am thinking now of a bridge setup....switch one diagonal pair for 10ms, then the other, and make the current half sinusoid in each direction.....we cant have mains transformers made up....ive managed to do this with a boost from 30v to 60v, but its just a train of half sines, not bipolar.....the 60v could be bucked back to the 30v so "no energy" was used.

author: Circuitsoft
author_rank: Newbie
timestamp: August 10, 2021, 06:08:50 pm
content: I would recommend (a) a power amplifier and (b) a transformer with a 16A output capability. Generate your sine wave on a device capable of acting as a pseudo-pll, and do phase comparisons between voltage on a load resistor (<1ohm) and voltage on the line.Since, you only need about 4v out on your transformer, you could use something like a Avel Lindberg Y236802 driven by a WONDOM AA-AB31184. One potential device for driving the sine wave could be a Teensy 3.5 with the Audio Library. The on-chip DAC is perfectly fine for driving said amplifier.
What hour/temperature rating of electrolytic input capacitor in this ACDC module - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 09, 2021, 08:13:18 pm
content: Hi,What is the input electrolytic capacitor hour/temp rating in this ACDC module... (RAC20-K)https://www.mouser.co.uk/datasheet/2/468/RAC20_K-1661844.pdf(The 24vout version, or any of them)Datasheet says "module" rated "16000 hours at 55degC"...that would imply 500 hrs at 105degc for its input electro capacitor......thats very poor....but why dont they just give the electro cap part number...and give assurance that they wont use a worse one in future?

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2021, 09:51:24 pm
content: You can't take theTreeFaringdon out of Faringdon.How is anyone here supposed to know what capacitor they use?.... and why would you want to operate it at 105'C? 55'C sounds like a much more sensible operating temperature.They use whatever capacitor lets them economically achieve 16k hrs at 55'C.I don't know of any potted module manufacturer that supplies a full BOM for what's inside. That would be ridiculous!EDIT: If you bother to read the datasheet you will see that it is rated at 85'C max anyway (max case temperature 95'C) with derating so you would be outside spec anyway.
Failure modes of Gigabyte GP-P750GM & GP-P850GM PSU (exploding mosfets) - Page 1
Forum section: electronics / general

author: station240
author_rank: Unknown
timestamp: August 09, 2021, 02:36:06 am
content: Gamers Nexus - Exploding Power Supplies: Gigabyte & Newegg Dumping Unsellable ProductBeen waiting for the results of their testing for a while, as we all like explosions don't we.It's one thing to have a really crap product (50% DOA/failure rate), it's another to not only not recall it, but to continue to find ways to force wholesalers and then end consumers to pay for said E-waste.Basic scam is if you want this latest high end video card, that's in limited supply, you have to buy this bundle that includes a crap PSU.Also sometimes this PSU destroys other components, including one youtuber who reports (in the comments for the above video) the entire PC caught fire (I'll be keeping an eye out of that video)
What is inrush current into Nissan Leaf on-board EV charger? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 07, 2021, 01:56:35 pm
content: Hi,Do you know what is the inrush current into a Nissan Leaf on-board EV charger?(or any other electric car)Consider worst case....eg connection to mains at mains peak.This must be known, because otherwise how do they spec the relays in the charge boxes?........................-------------------------------.............................-------------------------.................This 35A relay offers 50000 operations when switched with 35A in it...https://www.panasonic-electric-works.com/cps/rde/xbcr/pew_eu_en/ds_hes_en.pdfInrush (at mains peak) into a typical SMPS is likely to be 80A.So what is the lifetime of this relay with this 80A in the contacts?Due to contact bouncing, the full 80A at mains peak is likely to be experienced every time it switches.

author: Marco
author_rank: Super Contributor
timestamp: August 07, 2021, 02:04:59 pm
content: Quote from: Faringdon on August 07, 2021, 01:56:35 pmAre typical high power PFC circuits utter trash?A PFC doesn't require a large input capacitor and can limit inrush current with active control. There is no rush at all with PFC, it can just fill up the DC link at a leisurely pace and low peak current and then turn on the power supply.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 07, 2021, 02:10:07 pm
content: There's a precharge relay that closes before the main relay. Thus, the main relay experiences next to zero inrush while the precharge relay only sees a peak current limited by the precharge resistor.

author: wraper
author_rank: Unknown
timestamp: August 07, 2021, 02:13:25 pm
content: Quote from: Marco on August 07, 2021, 02:04:59 pmPFC by itself does not prevent inrush current. Until output capacitor charges to input voltage, it can do nothing about current flowing.EDIT: But since battery the in the car is under high voltage to begin with, it might be not a problem which needs to be dealt with.

author: Faringdon
author_rank: Super Contributor
timestamp: August 07, 2021, 02:15:01 pm
content: Thanks, yes..And as we know, they do use relay switched inrush resistors.....but these are only some 5 Ohms...and so peak inrush can be up to 80A....even more if mains is 265VAC and it gets connected at mains peak.QuoteThanks, you mean in the electric vehicles on-board charger?...how do you know this?.....for every electric car on the market?....for every future electric car that will get on the market?.....admittedly that would be great if correct.......but how do you know they do this?....ive searched the web for it and cant find anything.
My Bullsh*t Sensor is Pinging - Page 1
Forum section: electronics / general

author: Pugbutt
author_rank: Contributor
timestamp: August 05, 2021, 01:14:49 pm
content: Just got this in my social media feed. Mobile solar-panel factory! Sounds great, doesn't it? Notice the complete absence of any tech info in the campaign *cough* I mean 'article'.https://www.inceptivemind.com/maana-electric-terrabox-turns-sand-electricity-solar-panels/20389

author: Microdoser
author_rank: Frequent Contributor
timestamp: August 05, 2021, 02:57:29 pm
content: I think someone has become confused by how similar the words Silica and Silicon are. Sounds like they are hoping people with a lot of money also get confused in a similar way.

author: TimFox
author_rank: Super Contributor
timestamp: August 05, 2021, 03:50:07 pm
content: It still is common to add "silicone" to the confusion of terms.