Quickest way to get an expert solution to a problem is to get on the internet and claim your solution works. Very clever This Old Tony, very clever indeed.

I appreciate the civil engineer joke. Factor of safety and so on...

I can hardly wait for every This Old Tony's This New Videos. I'd also like to thank TOT and all the other KZfaq machinists for inspiring me to make a late-in-life career change to become a machinist. I've enrolled in our local comm. college and have recently begun making small bits of metal out of larger bits of metal for the first time.

as a Mexican, you got many smiles out of me on this video. as an engineer, you got many smiles out of me on this video

Just giving you a heads up, Tony. You might be reading a lot of anger from electrical engineers because of your calculations :-) For example: Your stepper motors take 12 Amps in total, however the Gecko Drive (as does any sane Stepper Motor Driver) uses current chopping to generate the constant current (of 4 Amps per motor). Due to this fact, it effectively works as a buck or stepdown converter. And consequently, the Gecko is nowhere near 4 Amps at the (up to 80 V) input voltage. If your motor has a DC resistance of 0.5 Ohms, then the idle power consumption per motor is I^2*Rdc which is 4^2 Amps^2 * 0.5 Ohms or 8 Watts. Thus in idle, your whole setup takes 8 Watts per motor or 24 Watts in total from the power supply. This relates to roughly 0.4 Amps at the 60 V input to the Gecko Drives. Added to this is now the *mechanical* power that you request from your motors in your machine. And this is where it gets really tricky. Worst case, your Gecko Drive will not chop current anymore, because the demanded mechanical power is so high. In this case, your calculations are correct, the full 4 Amps times 60 V input voltage will be requested from the power supply. However this is only a worst case calculation and I wonder if your stepper motors will handle 240 Watts of mechanical power (with an ideal efficiency). I don't know the efficiency of those motors, I will guess it is somewhere in the 80% range. This means that the stepper motor has, beside its idle power consumption _additional_ heat losses of almost 50 Watts. I think the motor will not be able to handle that :-) I guess what I wanted to say is, that your power supply is really overkill :-) Also the big cap might get you into trouble during powerup of the system, blowing the breaker all the time due to the startup current. By the way, the bridge rectifier definitely has to be put onto a heatsink! 12 Amps times roughly 2x0.8 Volts forward drop voltage is already 20 Watts, which is too much for the wimpy case without a heatsink. The hole in the middle is not there just for fun.

Impressive how many parts one can salvage from an old MP3 player.

I really enjoyed the show, a pleasure to watch as always. I am a civil engineer........ I wish I understood something of electronics, though I understood the unscrewing of those two bolts

Tony, thanks for this. Most of us are tooling guys, or CAD guys, programmers, or electronics guys. Not always a lot of overlap but you bring all of it to the table. Keep introducing the math! It's what keeps the electronics making sense!

For 30 years I designed power supplies; switchers, linears, battery chargers, and some jet engine starter/ generator stuff. I like to have some inductance between the full wave rectifier and the capacitors. That makes a real averaging filter and cuts down on the peak currents [both start up inrush and steady state 120 Hz]. I like snubbers across the rectifiers so I don't ruin AM radio reception. I look at capacitors in terms of ripple current rating, effective series resistance, effective series inductance, and if electrolytic, how many hours until the electrolyte has out gassed. If you pick up the capacitor with tweezers so you are not weighing the fingerprint, you can measure the rate of electrolyte loss. Small wires do not hurt anything, but they can get hot. Then it becomes a matter of the insulation on the wire's temperature rating. High temp insulation is hard to strip.

carbide [carbide] Not sure why but this cracked me up.

FULLL BRIDGEEEE RECTIFIERRRR!

I find it so difficult when you are talking to decide on the fly if you are being serious or not.....love it!! Keeps me on my toes!!! Keep up the amazing work!!!

when you took the mp3 player apart an the huge cap fell out i'll admit i laughed way to hard at that.

I’ve never heard of the bucket analogy, that’s a great way to put it! 2 electrical degrees, 21 yrs in electrical maintenance, never heard the bucket... Thanks

Your humor..... Love it

Your sense of humor gets me every time Tony! I think I watch you videos just to laugh at those moments! And occasionally, I learn stuff :P

Wow, it's been 10 years since I've seen someone with a Sandisk Sansa.. Amazing mp3 player. That one went waaaaaay over the "use by" date for me too. Respect!

It's amazing how these videos keep getting better and better, they were already top notch!

Love your humor laden educational videos with GREAT background music. I am no thermodynamic engineer but would have drilled and tapped the other end of the heatsink for mounting to the enclosure. This would help keep the heat away from the capacitor. A small valued/high Wattage surge resistor in series with the cap should reduce initial surge current and a high value bleeder resistor to ground will help prevent a shocking experience when poking around after being powered down. As you know, "The Experts" come out of the woodwork after you have created something that works for you. Keep up the good work and never let the smoke out of electronic components as you will never get it all back in again.

Hi Tony. Another great video! Always get excited when I see you've posted a new one. I used to work as an electronic engineer for a company which designed custom packaging equipment for the food industry. We used to drive big stepper motors from a pair of 24 volt regulated switch mode power supplies, wired in series to produce 48V. We never had any issues with back EMF damaging the PSUs or the stepper drivers. The advantage was they were cheap (24vdc is really common in industrial control), and available in compact din rail mounting cases with all the international certifications for sale all over the world. You'll never need to replace that beast though! That transformer could happily power 10 CNC routers 😉

Always amazing videos, thanks again for taking us along for the ride!

Your sense of humor is unmatched. Just very enjoyable to watch! :)

When a TOT video pops up, man you know it's going to be good. Thanks for getting the music and funnies back in, now I really have to concentrate again to see all the 'hidden' stiff. Kindest regards. Joe.

A man of my own heart! One thing goes wrong and now you own a transformer the size of a puppy

A couple things come to mind when I see your design for this simple un-regulated power supply: 1) The larger the capacitance bank, the larger your in-rush current will be. Therefore, make sure to size your fuses to the proper value for safe operation and use double-time delay fuses to prevent them from blowing every time you turn it on. 2) Un-regulated supplies do not maintain their output voltage when faced with large current draws. This means hard acceleration will pull down the DC bus voltage. Make sure your accel ramps are defined such that you aren't asking for too much motor speed at peak acceleration ('cause you won't get it). 3) Conversely, when decelerating the motor driver will "pump up" the DC bus voltage due to the regenerated voltage coming back from the motor. Make sure you have enough headroom to accept this voltage or things may go boom. Especially electrolytic capacitors (100V cap should be ok). 4) In servo and stepper systems, voltage equates to motor speed (because you have to overcome the motor's back-EMF to go faster) and current equates to torque. Your stepper drives are probably ok if they are rated for the nominal DC voltage of your supply, but remember the regeneration voltage that will be back-rectified. You might want to stick an o-scope on the DC bus and watch it as you acceleration and decelerate all axes simultaneously to make sure everything looks good under peak load conditions. Whew. That was a lot. Sorry for the book I wrote you!

just replaced the speed control board on my mini mill and then got watch this. its been a great day. thanks Farthead.

man i really like your channel. i've watched a video or 5 everyday. some in the morning, some at night, some both like today. your voice calms me. world is hectic right now but i get a few laughs in and learn about machining watching your channel. thanks for the relief .. i also enjoy you know some electrical engineering concepts D

Thanks, Tot, for making so many different topics understandable and of interest.

The little puns and goofy stuff (like the power joke and the Mp3 player) is only getting better. Makes these even more fun to watch. :)

NO! Not the Farthead block!!!!! I really like the bridge rectifier/Filter cap mount. Excellent job. Looks like you'll have more power to tackle even more larger projects.

More smaller capacitors are better for many reasons. Smaller caps are cheaper. If one cap fails you only have to replace one small cheap one. In the event of a capacitor faliure you get a soft failiure. This assumes the cap fails open circuit obviously if it fails short you will blow your low voltage AC fuse. The ripple voltage will cause the capacitors to heat up, several smaller caps will have a greater surface area to dissipate heat..... Mechanicaly I like the idea of using the heatsink to mount the smoothing capapacitor but heat is the enemy of electrolitic capacitors so I hope the heatsink does'nt get too hot. Love your videos the perfect mix of real knowledge, great thequnique and humor.

Thanks for the info Tony. I have been contemplating upgrading my power supply for my small CNC router as well. Now to find a new spindle motor so I can cut aluminum

Clear and lucid explanation - thanks! And also thank you for using the correct terms - current and power. I immediately kill any video where 'amperage' and 'wattage' are used.

@ThisOldTony I would add a discharge resistor across the capacitor so it does not retain its charge - for safety. Neither the classic PSU that you have nor the generic switching power supplies can't give excess energy (when you decelerate the steppers) back to the grid. Both of this power supplies have a capacitor at the output, tho the switching PSU cap is smaller because the frequency is higher - the pulses are more together. With no way to put the energy back into the grid when the current flows form the steppers to the PSU ("regenerative/generator braking") then the only thing that can happen is the voltage on the capacitor goes up. For the switcher (smaller caps) this means that the voltage overshoots will be larger. Meaning that the classic PSU is less likely to be damaged in this scenario. Also for this reason you did good to go with a 100V rated cap. As always enjoying your videos !!! Can't wait for the next one:D

OMG, This Old Tony, that poor Sansa Fuse... How could you?! Senseless desecration of one of the best MP3 players ever to exist aside, you created another great video. Thank you for the edutainment.

Love the music selection for this episode.

As someone who did a lots of electronic building in the past you made a very nice heat sink

Hi ToT. You make really great videos. I like this one about the power supply. As a former electrical/electronics guy, I have a recommendment. When you make stuff with ginormous™ capacitors, it doesn't hurt to put a high value resistor across the capacitor terminals, like a 100k or 1M ohms or so. A low wattage little guy that won't substantially load the supply or waste power, but during periods of inactivity, will slowly draw the voltage down to zero-ish. This is particularly nice protection if you happen to power the supply up while it's not connected to the motor drives. After you turn it off, the voltage will bleed back down to zero. Anyway, just saw that monstah capacitor and immediately though a nice axial resistor would be right at home across the terminals.

I greatly enjoy your videos. I don't know anything about anything you talk about, but you make it interesting and entertaining. Thanks!

Just a tip for you on your DIY heatsinks. If you cut your fins to sit vertically in operation you will pick up quite a bit of passive cooling in the form of "chimney effect", as opposed to stagnant horizontal laminar flow. Why heat sinks on the back of old high power audio amplifiers nearly always ran vertically. As to question of more small caps being better than one big one, the answer is yes. Due to many smaller caps having a lower combined ESR (Effective Series Resistance). Basically lowers the impedance of your filtering. (Pushes back harder, faster to smooth out bumps). On figuring safety overhead values for components, industry rule of thumb is 20%. Doc

That's what i did for my wood lathe earlier this year. 90vdc treadmill motor. 90vdc? I don't have that kind of power supply! Screw it, we'll take 120vac, rectify it, put a huge cap on the output. Boom. Wait, that's way too much voltage. Ah yes, variac to the rescue. Talk about precise speed control. Beauty.

the close-up slicing death of "Thanks f watching, / Fartheasd," with that musical accompaniment, is modern art

Love your videos and editing. A friend of mine with more experience in such things commented to me that you should never mount your capacitor on the same heat with the rectifier. In the event of the rectifier partially shorting , the excessive heat turns the cap into a potential bomb. Keep up the awesome videos.

great video Tony......keep up the great work.

Loving the Music, the lyrics doesn't make a lot of sense, but I really appreciate it. Mexican Independence day was the 15/16th of this month and this was a shocker that warms my heart inside. Also learning a lot from your videos and from the people in the comment section, love your humor and I really look forward to watching more from you, Gracias a ti Tony. :) PS: I think you meant "Gracias por ver". But hey, you couldn't be that good!

I subscribe to a lot of channels but I’m alway excited to see new upload from Tony. Keep of the good work!

As every other idiot out there, instead of thanking you for one of the best material on KZfaq, I will point out that at the end of the video it says: "gracia por mirar" when it actually should have said: "gracias por mirar ( or ver)”. I feel better now. Or worse.

I love all your videos Tony! You do a superb job!

Informal advice: Mount diode bridge above cap to avoid heating it which could shorten it's lifespan. Or better still side by side ensuring heatsink fins are vertical for slightly improved cooling. Multiple caps are better for lower ESR (= improved filtering) but not essential in this application. Can be added alongside for same benefit. Another commenter suggested inrush current on big cap could cause problems, which is plausible. A separate breaker or fuse in the PSU inlet would be desirable if don't have already. That's my unasked for tuppence worth! Keep up the slick humourous videos!

Love the vid. This is the type of thorough info helps me. One note - I have trouble knowing when the camera is sped up during machining. It may be obvious to seasoned machinist, but a 2x or 4x label might help us newbies. Thanks for the videos. Waiting for a patron page.

I'm impressed with your router! Nice job Sir!

Watching that list clip, I forgot for a minute that you built a router, not a CNC VMC. Nice.

You are the absolute best this old Tony !

Salutations my dear sir ! Enjoyed it much and I still think you're the brother I never had! 😎 A deep and convoluted mind..... yelp, love it ! Thanks for sharing and take care.

Tony, when you added the Teflon washers for the cap terminals, it looks like you put just a washer on top leaving a gap between the cap posts and those washers. If this is correct, all the clamping pressure you are applying with the screw is acting directly on trying to pull the terminals out of the capacitor. Add a small spacer or make a "t" profile custom insert to replace the plain washer.

My favorite video you have done so far lol love the Mexican music your the best, "diresta eat your heart out!"

Wow! you explained electronics like my teachers never could!

Good job, and very festive music! First video I watched after breakfast of huevos rancheros, which I'm sure will keep reminding me of your transformer all day, as I digest this...cheers!

Good idea using bridge to warm up capacitor. It will be easier to start this thing on cold winter morning.

I don't know what I enjoy more the video or your sense of humor with the music I love it😂😂😂😂😂😂😂😂 well your sense of humor...period

Well, I didn't really understand all of that, but, I sure did enjoy it. Keep making 'em, Tony, I enjoy them....

That music! Oh, the stuff with the numbers and metal chips flying everywhere was pretty ok too...

Hoooooooooooooly crap... I thought my prototypes sucked... but you made that actually work for as long as it did is amazing.

Loved my Sansa Fuze and was genuinely upset when it broke. Good to know that I can shake it down for some project components - 😁 lmao! Top notch production as always, ToT.

Ay, ay ay!!!!!!! Who knew a teeny little MP3 player has such a honkerin' big capacitor built in...great find! Pretty cool you hog dawgin' that cold rolled steel....very nice! Great video! Keep em coming!

I learned a TON, and I love your style. Thanks!

Very nicely done Tony! ATB, Robin

I was so happy when I saw you put down thermal paste on the heat sink. I know it seems common sense, but you would be surprised how many wouldn't.

This is my all time favorite channel

I strongly recommend a 6.8k 3 watt resistor across the capacitor terminals, to discharge the cap when the power is turned off. Also, you might want to look at AjaxCNC, they sell pre-made rectifier and capacitor combos, the rectifier board mounts to the top of the capacitor and is quite tidy. Just in case you need one in the future.

Even when various comments may already mentioned some of these points (or then not), I decided to add my 2 cents worth. The single big versus several small capacitors is mostly determined by the ripple current rating. The ripple current is not straight forward to calculate, but you can start wit a guess that it is same as the load current. So, whether it in this case is 12 A or something else, let's take that just as an example. If you look at the data sheet of the candidate capacitors, you often find that 4 smaller capacitors have more ripple current capability than a single capacitor of the combined capacitance. There are two factors to this - the combined surface area of the four capacitor is larger and thereby provides better cooling. The other part is that the parallel connection reduces the ESR (equivalent series resistance) to one quarter and likely the individual ESR numbers for the small capacitors are not 4 * the ESR of the big one. Then an ISO safety rule suggests that a bleeder resistor is dimensioned so that the capacitor voltage drops to a safe level (which varies by the environment) in 20 seconds. A lifetime expectation is tied to temperature. I have chosen to follow the Military Handbook rules and limit the component voltage to 0.7 * specified maximum. Similarly the current to 0.7 * specified maximum. That way the POWER is limited to 1/2. And finally, there are two parts to inrush current, the effect of the capacitor and the effect of the transformer. The rectifier bridge and wiring resistances can mostly be ignored as a first approximation. If the capacitor ESR is 0.1 ohm, at 64 V peak, you would in theory reach 640 A worst case. But then there is the inductance and resistance of the transformer. Those are normally expressed as a combined "regulation" factor which means the percentage drop of voltage from zero to full nominal load. Some tiny transformers may have as bad as 15 %, while really big ones (power distribution types) may have 2.5 %. The 1500 VA transformer likely has about 4 %. That translates to some 12 or 13 A at 115 V primary full load and a huge 1/0.04 * 12 A = 25 * 12 A or 300 A on the primary. Have your fuses or breaker selected accordingly!

Pretty result. The bucket analogy was good also.

THANK FOR TO LOOK!! Also: 1 cap > 4, no loss in the leads, no solder junctions to crack, no tracking down which cap blew.

Yay! New ToT video!!! (from 2 years ago... new to me though.)

Me encanta este video con una pasion tan fuerte! Craig

Think you made Forest Mimms Proud, Tony...even the screen writing/font was similar. Two minor things I noted were a vent hole for the Cap in your heatsink (Yustin case) and a Bleeder resistor. Keep'n us grinnin while schooling us is Art! Thanks for all your woik and dilitentness! ~PJ I been cravin some good Tamales....good ideer and music...must be time.

Tony, looks like you have used a crimp tool for uninsulated terminals on the yellow faston/spade connectors. There is a specific crimp tool for these insulated terminals. If the wires are not subject to vibration It's better to remove the yellow insulation and solder these connectors. You can use some heat shrink tubing for insulation if necessary. If you think there is a risk of vibration then use uninsulated connectors with the correct crimping tool. It is much easier to get a good crimp (cold weld) on this type of terminal.

ehh... not enough transformer jokes. I expected Optimus Prime to be the butt of the jokes... just kidding. excellent video, as always.

Dude, congratulations....that's a good result.

You sir are an amazing content provider, funny and intelligent

Nice of you to reach out to your Latino viewers. Great video!

Gigantic thumbs up for the mariachi. 😃😃😃

About big caps (capacitance not physical size) .. bigger results in lower ripple but thats is a double edged sword, also results in the charge pulses beinng extremely short. Like you dropped a spanned accross the transformer terminals. The mean current draw for the power you are using is a given, but the shorter the duty cycle, the higher the charging peak current, this can easily be 10x the mean, is brutal on the diodes. The copper in the traffo has a finite resistance, and V=IR so the higher the charge current te bigger the voltage drop due to that. These brutal ripple currents are also brutal on the capacitor. may resut in overheating, and for sure will reduce its operational life. resistores and transformers should last forever if operated in spec, but electrolytic cas have a very finite life and die of old age evenn if not used, and death is accelerated by high temperatures and big ripple currents. Shoulnd be an issue for occasional hobby use but is a concern in 50 year old antique equipment or anything used industrially so getting a hard life Not an issue for your application relly but in a idealised world of perfection (ie the extreme end of audiopphile ampifier design) the ideal is thus to have a quite small cap after the diode bridge to get a longer charge angle amd lower charge peak ... then have an inductor from that to a bigger reservoir cap. A so called pi filter. This gives a calmed down load on the mains and bridge (lower switching noise) simultainious with very low ripple. But inductors cost money Parralleling caps will lower the effective series resistance in the cap everything else being equal, but everything else is never equal and a single cap for times the value will have a different ESR anyway even if the same series , due to the different geometry. In reality in applicatios where we care about low ESR, these ays there are other types, of cap (notably organic dialectrics such as OSCON) that give massively better performance making parralleling moot as a way to get low ESR Love the humour and also beautiful camera work / editting. Thanks BR D

LOL ive watched through all the ThisOldTony videos countless times, and everytime i watch i find something else i missed. In the case of this video, i just had to pause it to laugh like a hysterical maniac after he says "you may have been taught that knowledge is power, well it's not, current times voltage is"

Thanks for sharing Tony, Billy in Canada

Alright, now I'm confused, ciorba, ciabatta or ceviche, Tony? Understandable if all three. Great video as always, I recently got out of building machines and started in maintenance. I've gotta say videos like this have been saving my ass, the tribal knowledge from youtube rock stars goes a long way. Especially in a world where so many things are farmed out now.

My only thought would be to have a beefy 100k-1meg ohm resistor across the cap (if it isn't already) to drain the cap when the system is powered down just for a tidbit of extra safety. Brilliant work as always. Dave jones/eevblog did a great episode about why a person would use 3 of a smaller cap compared to 1 bigger one; it comes down to BoM simplification/quantity discount efficiency as well as form factor awesomeness.

A huge improvement over the old power supply. It is a bit overkill for the realistic loads those motors will take but better to be over than under. Yes the bridge does NEED heatsinking. I would add a discharge resistor (say 4k7 1W) across the capacitor. 67v won't normally hurt but the impressive sparks if you short it will make you jump. A couple of smaller capacitors to help prevent conducted noise from the stepper drivers (they chop the current to the motors at several kHz). Say a 100uF and 1uF capacitor across the bigun will help prevent some of that electrical noise getting out to the big wide world. A common mode choke in the mains supply along with an X rated capacitor (across line to neutral) and two Y rated (from line and neutral to earth) capacitors across the mains will also help protect all the sensitive micro electronics in the other parts of the system from the high current switching noise. Oh and you need T rated (thermal) fuses for both the primary and secondary side of the transformer to survive the inrush currents. Strictly you could do a proper EMC design but just these simple measures will make a big difference. Keep up the great videos!

Hey Tony, that driver is a current chopper so I'd use the highest voltage you can pump into it up to its max. The drive will limit the current to the motor depending on your settings. Also, you can use a relay type pre-charge circuit to limit the current with a power resistor until a specific voltage threshold has been reached. Then the relay will switch to the main line in.

Top notch video, keep them coming.

That knowledge is power joke was amazing!

thanks for an awesome video Tony! :D

This Old Tony: At 9:00 on the bottom of the capacitor, that white dot. That is probably a vent hole, it is there to release the magic smoke in a controlled way (without explosion where metal bits fly around and stuff like that). When you mounted it at 11:20 I couldn't see a matching hole in your mounting plate. I would have drilled that third hole into it.

Fantastic video buddy!!! A Electrical engineer that is a machinist and designer too!!! Who of thunk it!!!!

I don't know why I'm watching this again.. but I'm sure happy I did.👍

Miracle of medicine... This Old Tony discovers new cure for urinary incontinence.

Capacitor explanation was great :D

With the oversized transformer, one needs to consider the amount of current it can deliver with its secondary shorted. This is the current the bridge rectifier will be asked to pass to the discharged filter capacitor on startup. If the filter capacitor is too large, the inrush current could be several hundred amps for a short duration on each power application. The bridge rectifier may take this abuse for a while, but it will likely fail far sooner than a proper design. In a past job I maintained several high voltage power supplies that supplied 10KV at up to 6A. These supplies had a circuit with six large SCRs between the mains and the three phase transformer primary to limit the inrush current, which provided a soft-start to the supply which kept the instantaneous current the rectifiers passed within their specifications.

Wow absolutely loved it Tony. Best Wishes n Blessings. Keith

I'm "civil engineer" myself (doing a PhD in signal processing systems), and I did not know about the regulated power supplies not being able to handle these back surges. I feel ashamed of myself.... Thanks for the nice insight