Beware with this trying to draw too much current from the series connection, because if the one supply goes into current limiting there is a good chance it will let the magic smoke out, because now the pass transistor in the supply shutting off is now going to become reverse biased base to emitter, and can easily fail. Even then most do have a diode across the output to clamp the negative swing, but this is often really under rated, and can easily go short circuit or burn out and go open.
Awww, you missed an opportunity here. When you first started the parallel example with low load I noticed the display on the Rigol showed that almost all the current was coming from the left supply. Would have been nice to explain that and show how it changes as the load increases.
Be aware of paralleling older power supplies with pots for controls, the voltages have to be set as close possible to the same voltage. Otherwise they will fight each other. Usually I adjust each supply close as possible and put a .1 ohm resistor in each positive terminal and take the output from the y of the resistors.
a lot of power supplies ďo not pull the voltage down if the output is above its set voltage, so the psu will the lowest voltage will not provide any power to its output while the voltage on the output terminals is higher. so one supply will be providing all the current and being overloaded.
Most triple output supplies have buttons or menus to do the series and parallel mode. If you put supplies in parallel externally, or with physically separate supplies, you are liable to let the magic smoke out. The way around this is to put a forward biased diode in series with each supply.
Also do note that you don't always get full sum currents when paralleling two or more supplies, it'll be limited by the difference in voltage output accuracies of each supply. Based on actual output voltage, one of the supply will always load the other by a fraction dependent on the resistance between the two supplies parallel connection wiring and the difference in their accuracies. In most hobby use case this is not a concern but if you're doing this at work to make some electrical measurement, do take note of this behavior.
Great point...folks need to be very careful that they don't connect the ports to the GREEN (earth ground) when trying to configure in this manner. And thanks for the reminder about our 832A's B channel and 5V channel having a common ground!
Thanks for the tip. My power supply has buttons to select independent/series/parallel modes for the two outputs, and I never really looked into what they did. I've never needed the extra voltage or current yet, but it is good to know it is there if I ever need it.
after connecting 2 supplies in parallel, they start to feed current to each other. You can see it at 6:53 - without any load, one supply already uses 45mA, and the other 21mA. That is of course average values, as they constantly try to feed each other. I guess setting a diodes in the wires will prevent the current flowing to the supplies, only from?
Maybe others have said this, but most PSUs will only give you so many watts of power and that number will be something less than its rated volts times its rated amps. So, a 30V/30A PSU might only be rated for 60 watts, not 90. You must check this for yourself in the literature, because the better marketing angle is to state the volts and amps. Good tip on some channels having a common ground. I did not know about that.
ok? Yes. I'm OK... thanks for asking (100 times...) ;-) I know verbal ticks are really hard to defeat... ok? Good info, btw... I didn't want to wire them in series or parallel because I was scared something would short...
Thanks for the video. I scrolled through all your videos in the hope to find video about your electronic load, unless I missed it I could not find it. Do you have anything for us?
idk if anyone will read this but, if i have two psu's connected in series and i want to limit the current to 10ma for testing high voltage zeners, how do i set the current? 5ma on both supplys? 10ma one one supply? what is the proper way to current limit series supplys?
Beware with this trying to draw too much current from the series connection, because if the one supply goes into current limiting there is a good chance it will let the magic smoke out, because now the pass transistor in the supply shutting off is now going to become reverse biased base to emitter, and can easily fail. Even then most do have a diode across the output to clamp the negative swing, but this is often really under rated, and can easily go short circuit or burn out and go open.
Awww, you missed an opportunity here. When you first started the parallel example with low load I noticed the display on the Rigol showed that almost all the current was coming from the left supply. Would have been nice to explain that and show how it changes as the load increases.
I wish you lived closer!!!! We would have so much fun with all this stuff!!!!! The wife says NO!!!! Great video, as always!!!!!
ImsaiGal gave me use of the entire garage which I love her for
I think I was "that guy" lol 😂 love your vids thanks for the extended info!
Be aware of paralleling older power supplies with pots for controls, the voltages have to be set as close possible to the same voltage. Otherwise they will fight each other. Usually I adjust each supply close as possible and put a .1 ohm resistor in each positive terminal and take the output from the y of the resistors.
a lot of power supplies ďo not pull the voltage down if the output is above its set voltage, so the psu will the lowest voltage will not provide any power to its output while the voltage on the output terminals is higher. so one supply will be providing all the current and being overloaded.
Most triple output supplies have buttons or menus to do the series and parallel mode.
If you put supplies in parallel externally, or with physically separate supplies, you are liable to let the magic smoke out.
The way around this is to put a forward biased diode in series with each supply.
Also do note that you don't always get full sum currents when paralleling two or more supplies, it'll be limited by the difference in voltage output accuracies of each supply. Based on actual output voltage, one of the supply will always load the other by a fraction dependent on the resistance between the two supplies parallel connection wiring and the difference in their accuracies.
In most hobby use case this is not a concern but if you're doing this at work to make some electrical measurement, do take note of this behavior.
Great point...folks need to be very careful that they don't connect the ports to the GREEN (earth ground) when trying to configure in this manner. And thanks for the reminder about our 832A's B channel and 5V channel having a common ground!
Thanks for the tip. My power supply has buttons to select independent/series/parallel modes for the two outputs, and I never really looked into what they did. I've never needed the extra voltage or current yet, but it is good to know it is there if I ever need it.
after connecting 2 supplies in parallel, they start to feed current to each other. You can see it at 6:53 - without any load, one supply already uses 45mA, and the other 21mA. That is of course average values, as they constantly try to feed each other. I guess setting a diodes in the wires will prevent the current flowing to the supplies, only from?
Maybe others have said this, but most PSUs will only give you so many watts of power and that number will be something less than its rated volts times its rated amps. So, a 30V/30A PSU might only be rated for 60 watts, not 90. You must check this for yourself in the literature, because the better marketing angle is to state the volts and amps. Good tip on some channels having a common ground. I did not know about that.
ok? Yes. I'm OK... thanks for asking (100 times...) ;-) I know verbal ticks are really hard to defeat... ok?
Good info, btw... I didn't want to wire them in series or parallel because I was scared something would short...
i don't even know where to source equipment but I'm learning😀
Thanks for the video. I scrolled through all your videos in the hope to find video about your electronic load, unless I missed it I could not find it. Do you have anything for us?
ua-cam.com/video/OlqymCSZ4Ek/v-deo.html
ua-cam.com/video/mSFoWyL2_k4/v-deo.html
@@IMSAIGuy Thank you for the links.
Merci for this video.
Question, doesn't having your oscilloscope on top of your power supply introduce stray noise onto the oscilloscope's measurement?
both are shielded. and the supply is linear. so I don't think it is an issue. My LED lights create the most electrical noise in the shop
idk if anyone will read this but, if i have two psu's connected in series and i want to limit the current to 10ma for testing high voltage zeners, how do i set the current? 5ma on both supplys? 10ma one one supply? what is the proper way to current limit series supplys?
10mA on each
@@IMSAIGuy Wow that was super fast Thank you!! I don't comment a lot but I really appreciate your videos and appreciate the way you explain subjects!
1:25 to get +/-.
3:25 series/parallel diagram.
Does that work with 2 or more power supplies?
many but not all
if one fails/burps/ then all die... right
not if designed right. the other will current or voltage limit.
@@IMSAIGuy in non death mode,,, u might need protection diodes...
your first 2 series examples are exactly the same, with the exception of which terminal(s) you make "ground"
yes, not much of a change to do very different things