Endless Sphere

Electron, I'm an ol' guy now...and have forgotten the specifics of this calculation I did back in 2012. There should be a thread on here with a deeper discussion. Note the significance of switching losses versus conduction losses at high PWM frequencies.

A little off the thread tangent, but relevant. I built the house in 1987, and I personally installed a 5 ton R22 system. I bought a 30lb bottle of R22 just to have it back then... cost about 100 bucks. Fast forward to last year. Old system was costing me a total of 500 bucks a month to run during ju...

I've salvaged components a few ways. The delicate way is to use a solder sucker often called a desoldering station. I use a METCAL-SP440-Desolder-System-with-Handpiece-SP-PW3-11 I would use this to get temperature sensitive components off the board. Then I have a dedicated toaster oven. I put the bo...

Gents, I have for sale a great F.W. Bell Model 9640 Gaussmeter complete with STB4-0404 probe. This is a very thin probe that can get between a rotor and stator. I is up on that auction site that we all know and love... haha... but would give preferential treatment to ES members. Unit has been cleane...

Gents, I have 3 of these ACDC Electronic Model EL-750 Electronic LOAD Bank that are perfect for Lithium Battery cyclic life testing or power supply testing. I have them up on that auction site that we all know and love... haha... but would give preferential treatment to ES members. All units have be...

I think you should take a look at the classic A123 LiFePO4 pouch cells. IIRC they are spec'ed to around 300 amp peak discharge.
reference http://www.a123systems.com/automotive/products/cells/

This was a very important parameter for us in the aerospace industry. We often baked the magnets at various temperatures for various times and developed a matrix of their specific demagnetization characteristics so that we could keep our systems performance up to par for decades in space. Outside of...

nep, thanks for stepping up to this huuuuuge job! As you said, without the move to modern servers, operating systems, and bbs software we were a sitting duck... one hacker away from loosing everything.

Thanks again!

Some thoughts as this has been my summer of A/C repair/replacement and large industrial dehumidifier repair. First, there are some decent R22 replacements that don't have flammable components. R407c is a decent substitute in R22 A/C systems. It needs POE oil however. If you can replace all the miner...

Oreilly auto parts has one in stock the ultima rebuild for $191 does this look like yours? They will ship to you. OK i looked closer once I posted this. The manual transmission one is out of stock. The automatic transmission is in stock. The difference looks like it is just the Pulley. So take your ...

Ahhhh this is so easy...not! Just define all mechanical failure modes as noncredible in the FMECA because of pull test on crimped connectors. Then do the rest according to MIL-HDBK-217 ... easy peasy... yea right. Methy, about 8 years ago now, I was contemplating getting into battery systems for mob...

If it's got 140,000 to 160,000 it's likely the brushes are just worn. I've rebuilt a ton over the years... only had one with a blown diode, and then it was in one leg of the 3 phase only, so the alternator still had minimal output, and that was back in 1976. Then again, if you can't get an alternato...

I was looking into this about 8 or so years ago... the ultrasonic heads are available on the secondary market. Back then I was looking at $8K to about $14K to set up an ultrasonic wire welding station. This will get you started: https://www.sonobondultrasonics.com/welders-bonders/metal-welders Look ...

Thought I would add an update if anyone in the future goes down this road for an Internet of Things Project. I got the entire system working! Whooppee. Now getting push services to my iPhone for laboratory parameters. 1. Use the NodeMCU ESP8266 development board with the built in USB driver. About 4...

liveforphysics wrote:All mature EV power trains will end up reluctance based eventually.

QFT... gents mark Luke's words above. I have "heard" that also from my interactions from 8 to 12 years ago... It has been in the pipeline waiting for the right power level, control electronics, etc. to come to the forefront.

Marty the nodes are ESP8266's running nodeMCU software. Each WSP8266 have 8 input pins. What we want to do is send a push to a cell phone if any pin changes state. It is best if it is a "Notification" in iPhone land where you have to notice and disposition it. Like you get with a text, or like I get...

I am working on an internet of things project and starting to investigate push services to an iPhone. Is anyone up to speed with pushbullet.com 's services? Does it just push to your phone with their phone app using the API? Can it send an email to your phone using the API directly? Can it send an S...

This was a very nice flow chart from UPS, but it is dated 2015. I know the Air portion has changed in early 2017, but does anyone know if the GROUND portion is still valid? I searched and searched UPS but couldn't find their UPS Ground requirements for CONUS. https://www.ups.com/assets/resources/med...

I support your grounding scheme... I always called it a star point ground. Also applaud the idea that ground is never absolute. " I am currently debating whether I need to protect from overcurrent or just put that responsibility on the user. There are plenty of N-Channel mosfet drivers which include...

...Still looking for the turn-key CAN board that's as cheap as a Bluetooth ($10) -methods I'll bet I am missing something with respect to modern CAN standards... but 12 or so years ago I rolled a CAN system based on the MCP2510 from Microchip, then rerolled some nodes with PIC's that had CAN interf...

Yes, you interpreted my suggestion perfectly methods. I think you have around 10 extra pins, and this might be a good use for 4 or 5 of them.

How about the DC-DC converter being a "plug in module?" Where the main board is scarred for it? You could originally start out with no DC-DC then do a module for charging your independent 12V source based on the first or largest sale of primary battery voltage and 12V battery chemistry.

That thing arc under load disconnect? ... then weld under subsequent turn on?

Looking for good small lot acrylic laser shop for small parts 1"x12" with holes in the USA. Likely first runs 10 to 20 parts. Any recommendations appreciated!

okashira thanks for the clarification! I have a half dozen sample chips in my lab and never got around to building prototype sensors... (the story of my life.) Glad to know they will work as stated in data sheet.