benchtop power supply recommendation for robot?

[lots o tots]

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.

Needs

• I 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 possible
• Would i need more than 1 output?
• CC as always

Preferences

• I would prefer used equipment as it seems to be the most bang for the buck, but would consider newer equipment
• ETL, 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 ask
• Nothing too old (no analogue meters).
• linear vs SMPS? not sure

-LOT

[ledtester]

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.

[rvalente]

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

[lots o tots]

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.

it 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.

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

The HP 62xx and HP 63XX seem to be analogue only and way too deep. (large).  I dont have a deep bench.

[rdl]

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.

[ledtester]

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-motors

There 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.

[SpecialK]

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 HM302
https://www.amazon.ca/dp/B0852JZQZR/?coliid=I1LWIV85KC0UA7&colid=NQK1GIZPFFMA&psc=1&ref_=lv_ov_lig_dp_it

Not 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.

[radiolistener]

There is well known PSU that perfectly fits your needs: KORAD KA3005D

This 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 it

This is really very good PSU.

[tszaboo]

Just make sure it has enough power for the deadly lasers.

[lots o tots]

There is well known PSU that perfectly fits your needs: KORAD KA3005D

This 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 it

This is really very good PSU.

Tempting. At 14",i am still looking for a solution that is smaller, if it exists.

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.

i 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.

It's a tall order to find a CSA stamped dual 30V 5A power supply for $200 Canadian 3.5 digits display.  Good luck!

A person can dream

[lots o tots]

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

[ledtester]

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/9r6liwNnXaY

You might find this video helpful: https://youtu.be/i7gWv6kb7mY

Note 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.

[rvalente]

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"

[lots o tots]

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/9r6liwNnXaY

You might find this video helpful: https://youtu.be/i7gWv6kb7mY

Note 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.

that 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.

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"

They do look quite appealing.  I just need to wait for a good deal.

[SpecialK]

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

[ledtester]

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/#msg3210760

Both 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

[lots o tots]

Okay,
it's down to two choices.

1:  The Korad power supply which keeps on coming up again and again in many recommendations OR
2:  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.

accuracy
reputable 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?

[Teknic_Servo]

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-motors

There 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.

Hi 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 at https://www.teknic.com/contact/.

Thanks,
Jon K – Teknic Servo Systems Engineer

[radiolistener]

Korad is smaller, i am not sure how many count error it is.  apples to oranges.

short run at several settings shows the following results for KORAD KA3005D:

Unloaded output.
Format is [setting voltage] = [actual output]:
0.10 V = 0.10159 V
0.50 V = 0.49860 V
0.70 V = 0.69990 V
1.00 V = 0.99695 V
1.01 V = 1.00594 V
1.20 V = 1.19851 V
2.00 V = 1.99745 V
3.00 V = 2.99477 V
3.20 V = 3.19320 V
4.00 V = 3.99448 V
5.00 V = 4.99893 V
6.00 V = 5.99988 V
7.00 V = 6.9970 V
8.00 V = 7.9970 V
9.00 V = 9.0025 V
10.00 V = 9.9969 V
11.00 V = 11.0012 V
12.00 V = 11.9992 V
13.00 V = 12.9997 V
14.00 V = 14.0037 V
15.00 V = 15.0026 V
16.00 V = 16.0053 V
17.00 V = 17.0020 V
18.00 V = 18.0143 V
19.00 V = 19.0084 V
20.00 V = 20.0103 V
21.00 V = 21.0092 V
22.00 V = 22.0081 V
23.00 V = 23.0159 V
24.00 V = 24.0120 V
25.00 V = 25.0161 V
26.00 V = 26.0132 V
27.00 V = 27.0226 V
28.00 V = 28.0181 V
29.00 V = 29.0227 V
30.00 V = 30.0234 V
31.00 V = 31.0211 V

Loaded output test.
Format is [voltage setting] => [unloaded voltage] / [loaded voltage] @ [load current]
3.20 V => 3.19293 V / 3.17939 V @ 4.138 A
5.00 V => 4.99890 V / 4.98319 @ 4.803 A
9.00 V => 9.0027 V / 8.9877 V @ 4.630 A
12.00 V => 11.9991 V / 11.9808 V @ 4.703 A
19.00 V => 19.0084 V / 18.9909 V @ 4.798 A
24.00 V => 24.0118 V / 23.9928 V @ 4.751 A
30.00 V => 30.0231 V / 30.0025 V @ 4.809 A

It 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 V
Max 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 mA
Max current setting is 5.100 A it leads to actual output 5.1001 A

It has calibration mode, so you can recalibrate it in case of needs

When 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.

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.

Regarding 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

[wizard69]

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.

If 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. 

any feedback is greatly appreciated.

Needs

• I 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 possible
• Would i need more than 1 output?
• CC as always

• Don'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.

Preferences

• I would prefer used equipment as it seems to be the most bang for the buck, but would consider newer equipment
• ETL, 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 ask
• Nothing too old (no analogue meters).
• linear vs SMPS? not sure

This 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.

-LOT

I 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.