benchtop power supply recommendation for robot? - Page 1
Forum section: electronics / testgear

author: lots o tots
author_rank: Contributor
timestamp: October 11, 2020, 03:52:16 am
content: Hello,I have read the existing threads on power supply recommendations. I do have some specific needs and preferences and was wondering if i could get some further assistance.The primary use for this will be the construction of a robot with dual motors. I dont think i need advanced features. The motors will be driven by a pre-assembled driver kit purchased online.any feedback is greatly appreciated.NeedsI was thinking something that could handle 24V and 5 amps, so a 30V, 5A supply.I am hoping to keep this to $150 USD ($200 CDN), although i know that may not be possibleWould i need more than 1 output?CC as alwaysPreferencesI would prefer used equipment as it seems to be the most bang for the buck, but would consider newer equipmentETL, CSA or UL listed. I dont want to burn my place down.prefer 4 digit or more.Small footprint is important. my bench is not deep. Depth of power supply cannot be too large. 8" or less preferred, but can go as much as 10". I know this may be a big askNothing too old (no analogue meters).linear vs SMPS? not sure-LOT

author: ledtester
author_rank: Super Contributor
timestamp: October 11, 2020, 08:04:19 am
content: Is this a mobile robot?Have you considered batteries? For instance, the robots in the FIRST Robotics competition run on lead-acid batteries. Over-current protection is achieved by the use of resettable circuit breakers.Motors don't need clean, regulated power that bench power supplies provide. Usually sensors provide feedback to a motor controller to regulate the power delivered to the motor.Update: It would be helpful to know what kind of motors you're using (servo, stepper, bldc...) and how much power you need.

author: rvalente
author_rank: Frequent Contributor
timestamp: October 11, 2020, 02:16:37 pm
content: Thake a look at older HP 62xx and 63xx, easy to find, great stability and low noise, very easy to find. Basically a tireless work horse

author: lots o tots
author_rank: Contributor
timestamp: October 11, 2020, 06:06:43 pm
content: Quote from: ledtester on October 11, 2020, 08:04:19 amit will be powered by batteries, eventually for mobility, but will be stationary at first. It will include a bunch of sensors. as far as type of motor, i dont know yet as i am not familiar yet with the options. my goal is to achieve approx 0.5 meters/second carrying 40lbs with wheels.Quote from: rvalente on October 11, 2020, 02:16:37 pmThe HP 62xx and HP 63XX seem to be analogue only and way too deep. (large). I dont have a deep bench.

author: rdl
author_rank: Super Contributor
timestamp: October 11, 2020, 07:48:13 pm
content: The motors, once you decide on the type, will not need a precision bench type supply and even while on the bench could still be run from batteries. I would get a small lab type bench supply for developmental work on the electronics to start with. The 8" depth requirement is pretty restrictive. Bench test equipment has never been optimized in that direction. Usually they're made wide and short for stacking or tall and narrow too take less width. Short depth never seems to be a consideration.

author: ledtester
author_rank: Super Contributor
timestamp: October 11, 2020, 09:09:24 pm
content: Here are some caveats to be aware of when running a motor on a DC power supply:https://www.power-supplies-australia.com.au/blog/power-supplies-use-dc-motorsThere are power supplies especially made for running motors, e.g.:https://www.teknic.com/products/servo-motor-dc-power-supply/Clicking on the (+) bullets in the above link will reveal the ways these power supplies differ from conventional bench power supplies.

author: SpecialK
author_rank: Regular Contributor
timestamp: October 11, 2020, 10:06:32 pm
content: It's a tall order to find a CSA stamped dual 30V 5A power supply for $200 Canadian 3.5 digits display. Good luck!I found this on Amazon and am tempted to buy one for a teardown.Hanmatek HM302https://www.amazon.ca/dp/B0852JZQZR/?coliid=I1LWIV85KC0UA7&colid=NQK1GIZPFFMA&psc=1&ref_=lv_ov_lig_dp_itNot as good as my Korad KA3005D because it doesn't have memory presets and is a switcher. But it is kind of half the price.

author: radiolistener
author_rank: Super Contributor
timestamp: October 11, 2020, 10:59:38 pm
content: There is well known PSU that perfectly fits your needs: KORAD KA3005DThis is legendary PSU, with very good voltage precision with OVP/OCP/OV/OC modes which covers all your needs.Allows to setup voltage from 0 to 30 V with 10 mV resolution and current from 0 to 5 Amps with 1 mA resolution.And after all, this is linear power supply, which means it has very low noises, better than very good SMPS.You can buy a new one from 70 USD, I bought it for 80 USD and happy with itThis is really very good PSU.

author: tszaboo
author_rank: Super Contributor
timestamp: October 11, 2020, 11:29:14 pm
content: Just make sure it has enough power for the deadly lasers.

author: lots o tots
author_rank: Contributor
timestamp: October 12, 2020, 01:47:24 am
content: Quote from: radiolistener on October 11, 2020, 10:59:38 pmTempting. At 14",i am still looking for a solution that is smaller, if it exists.Quote from: rdl on October 11, 2020, 07:48:13 pmi suppose the only option for smaller is to make one myself. I am not a fan of the interface of some of the kits as per Dave's videos for DIY. also one caught on fire.Quote from: SpecialK on October 11, 2020, 10:06:32 pmA person can dream

author: lots o tots
author_rank: Contributor
timestamp: October 12, 2020, 02:41:36 pm
content: i am thinking of a different solution. Bare with me.is it possible to get a decent power older supply with a 3 digit voltage and mod/replace the displays with a 5 digit on ebay? i know it may not be super elegant, but that is okay. i am not sure of the wiring that does to the displays, but the ebay ones take 3-12V from my understanding. i am thinking it should be possible. Thoughts?https://www.ebay.com/sch/i.html?_nkw=panel+meter+%225+digit%22

author: ledtester
author_rank: Super Contributor
timestamp: October 12, 2020, 03:40:44 pm
content: You'll have to find a 3-12V power source somewhere in the power supply.Find out what the update rate is - if it's only a couple of updates per second you might be disappointed.The displays might have quirks like this:https://youtu.be/9r6liwNnXaYYou might find this video helpful:https://youtu.be/i7gWv6kb7mYNote that there will be a voltage loss between the power supply and your application circuit due to the resistance of the leads, so even if you measure the power supply voltage very accurately it may not reflect the voltage being delivered to your circuit.

author: rvalente
author_rank: Frequent Contributor
timestamp: October 12, 2020, 04:53:30 pm
content: Take a look at KIKUSUI PAK power supplies, they're very very powerful in a very small package. I've a 20V 18A and is the size of a "pound cake"

author: lots o tots
author_rank: Contributor
timestamp: October 12, 2020, 09:35:44 pm
content: Quote from: ledtester on October 12, 2020, 03:40:44 pmthat video was the inspiration for my comment, however, he had some major issues powering the displays off of the board without some involved modificiations. I was thinking a less elegant and simpler solution was to just power both displays by a separate linear 5v power adapter and feed it through.i think updating an existing display might be easier than adding to an existing analouge provided i can find the display update rate as you suggested.Quote from: rvalente on October 12, 2020, 04:53:30 pmThey do look quite appealing. I just need to wait for a good deal.

author: SpecialK
author_rank: Regular Contributor
timestamp: October 12, 2020, 11:41:33 pm
content: I'm liking this. 30V 10A $99 CDN with free delivery.https://www.amazon.ca/dp/B087TK6ZM2/?coliid=I3ODGRYBCTDAER&colid=NQK1GIZPFFMA&psc=1&ref_=lv_ov_lig_dp_it

author: ledtester
author_rank: Super Contributor
timestamp: October 13, 2020, 01:08:32 pm
content: I have some of those 5-digit volt meters and I was disappointed with their performance. I was never able to calibrate it well enough using the small trim pot. I also wanted one with a faster update rate.I'd rather have a meter that's off by at most 1 count (i.e. +/-1 in the last digit) than a higher precision meter that has an error of +/- 30 counts.About power supplies... there's kinda two questions floating around in this thread: what power supply to use for robot motors and what power supply to get that has high resolution meters. I still suggest just using batteries for the motors. For a general purpose bench power supply, have a look at this recent thread:https://www.eevblog.com/forum/beginners/cheap-power-bench-supply-any-recommendations/msg3210760/#msg3210760Both the Korad and Gophert supplies have digital controls (i.e. a rotary encoder), not a potentiometer for voltage and current settings.The Gophert has a low profile which you might find attractive. There is also a project underway to develop a LCD front panel display for it:https://youtu.be.com/51xeZVMzJyQ

author: lots o tots
author_rank: Contributor
timestamp: October 14, 2020, 08:10:38 pm
content: Okay,it's down to two choices.1: The Korad power supply which keeps on coming up again and again in many recommendations OR2: A used reputable traditional brand name (HP/BK precision etc....) pretty much the exact same functionality (almost) and same interface (output/ OV/OC protection) for a good price.accuracyreputable name, is a deal. V: 19.99 counts, 0.5% + 2 count, A: 1%+5 digits, 1.999 count but is that worth it?Korad is smaller, i am not sure how many count error it is. apples to oranges.Safety is important to me and i dont like no testing laboratory stamp on the Korad, but the design seems to be liked on so many tear downs online.last minute thoughts?

author: Teknic_Servo
author_rank: Newbie
timestamp: November 09, 2020, 06:36:33 pm
content: Quote from: ledtester on October 11, 2020, 09:09:24 pmHi ledtester,I’m an engineer with Teknic and I recently came across this thread and your comments about the differences between bench power supplies and supplies designed for powering motors.Based on that comment, I thought that you might be interested in a white-paper comparison of the three types of DC power supplies most frequently used in motion control applications. These types of supplies are: unregulated “bulk linear” supplies, regulated PWM switching supplies, and a hybrid regulated “resonant mode” supplies.This article (https://www.teknic.com/selecting-power-supply/) details the pros and cons of these power supply types, and should prove useful when trying to pick the right type of supply for motion control applications. Please note that Teknic doesn’t manufacture batteries or adjustable bench power supplies (so we won’t be a good fit for this application), but the information contained in that article is applicable across a large range of applications.I hope this helps. If you have any questions, or would like to talk about a specific application, please feel free to give us a call at 585-784-7454, or use our "Contact Us" form online athttps://www.teknic.com/contact/.Thanks,Jon K – Teknic Servo Systems Engineer

author: radiolistener
author_rank: Super Contributor
timestamp: November 10, 2020, 09:50:12 pm
content: Quote from: lots o tots on October 14, 2020, 08:10:38 pmshort run at several settings shows the following results for KORAD KA3005D:Unloaded output.Format is [setting voltage] = [actual output]:0.10 V = 0.10159 V0.50 V = 0.49860 V0.70 V = 0.69990 V1.00 V = 0.99695 V1.01 V = 1.00594 V1.20 V = 1.19851 V2.00 V = 1.99745 V3.00 V = 2.99477 V3.20 V = 3.19320 V4.00 V = 3.99448 V5.00 V = 4.99893 V6.00 V = 5.99988 V7.00 V = 6.9970 V8.00 V = 7.9970 V9.00 V = 9.0025 V10.00 V = 9.9969 V11.00 V = 11.0012 V12.00 V = 11.9992 V13.00 V = 12.9997 V14.00 V = 14.0037 V15.00 V = 15.0026 V16.00 V = 16.0053 V17.00 V = 17.0020 V18.00 V = 18.0143 V19.00 V = 19.0084 V20.00 V = 20.0103 V21.00 V = 21.0092 V22.00 V = 22.0081 V23.00 V = 23.0159 V24.00 V = 24.0120 V25.00 V = 25.0161 V26.00 V = 26.0132 V27.00 V = 27.0226 V28.00 V = 28.0181 V29.00 V = 29.0227 V30.00 V = 30.0234 V31.00 V = 31.0211 VLoaded output test.Format is [voltage setting] => [unloaded voltage] / [loaded voltage] @ [load current]3.20 V => 3.19293 V / 3.17939 V @ 4.138 A5.00 V => 4.99890 V / 4.98319 @ 4.803 A9.00 V => 9.0027 V / 8.9877 V @ 4.630 A12.00 V => 11.9991 V / 11.9808 V @ 4.703 A19.00 V => 19.0084 V / 18.9909 V @ 4.798 A24.00 V => 24.0118 V / 23.9928 V @ 4.751 A30.00 V => 30.0231 V / 30.0025 V @ 4.809 AIt has 39.99 digits for voltage and 5.999 digits for current.Min voltage setting is 0.01 V it leads to actual output 0.0092 VMax voltage setting is 31.00 V it leads to actual output 31.020 V.Min current setting is 0.001 A it leads to actual output 1.527 mAMax current setting is 5.100 A it leads to actual output 5.1001 AIt has calibration mode, so you can recalibrate it in case of needsWhen output is off, the display works to setup regulation voltage/current.When output is on, the display works as multimeter to show actual voltage/current, this is very useful.And you can change output voltage/current with enabled output. When you enter edit mode, display shows regulation voltage/current and has flashing digit. When edit mode is completed, it switch back to multimeter mode.Quote from: lots o tots on October 14, 2020, 08:10:38 pmRegarding to the safety, KORAD KA3005D has a fuse and grounded case.Also it has ground terminal near (+) and (-) output terminals.It has transformer isolated output, so it looks pretty safe.Regarding to malfunctions, I hear that one people catch the control register chip malfunction on the control panel after 5 years of usage, it leads to 18V output on the terminals when output is disabled. He replaced the chip and it fixed the issue. I'm not sure if new revisions added protection to prevent 18V on the output when control register chip fails, but people who catch this issue is very happy with this PSU

author: wizard69
author_rank: Super Contributor
timestamp: November 11, 2020, 10:14:09 pm
content: Quote from: lots o tots on October 11, 2020, 03:52:16 amIf you want max performance out of those motors you need to understand how to size a power supply for steppers. One of the better online explanations can be found here:https://www.geckodrive.com/.You will have to figure out where, as the web site has changed a bit since I last visited.Basically you need to know the steppers inductance to size the supply. As for the actual supply, the supply doesn't need to be fancy, a transformer, rectifier and filter cap can be good enough in many cases. If you go with a switching supply make sure it is rated for use with stepper motor drives.QuoteDon't think, understand the requirements of the stepper and drives you will be using.For the steppers or the entire robot? You can do a cheap power supply for hte stepper sna probably be OK price wise. However since we have no idea what is happening with the rest of machine it is hard to say how much you will be spending on supplies.How would we know? In general you need one for the motors, one for the controller and one for I/O but how you build the machine is up to you.CC? You are not making any sense here. Constant current supplies really don't fit the usage here. For steppers you don't even need voltage regulation in many cases. Your controller board will need whatever it specifies.QuoteThis list makes little sense to me. Sure you want safe supplies but building a robots requires that you specify the proper supply. For the steppers I wouldn't even bother with "lab" supply and simply buy a supply designed and properly sized for the drives. I really don't see the point in an expensive lab supply for driving stepper drives.I'm not sure what your robots smarts will be but even here there is little reason to supply it with an expensive lab supply. So that leaves any experimental work you will be doing. In that case you will need a variable voltage supply in the 0-24 VDC range.QuoteI might have a different approach to robot building but I really don't see a need for expensive lab supplies for much of a build. Use a lab supply where you are developing things.