Combining 24V Power Supplies to get more Amps

Esieli · Apr 23, 2020

I have an application where I need around 60 Amps of 24V.

Most 24V PS go up to 40A, so I need to be able to add them in parallel.

Puls power supplies are capable without any extra needed components, but if I were to use a 24VDC PS from anyone else, how would I do it?

I was told something about an Oring diode. I can't seem to find that anywhere for this high of current, so is a traditional diode after each PS not enough? Or is that even necessary?

Thank you in advance.

AkaHammer · Apr 23, 2020

several years back i used Siemens you can parallel them with no additionally components did that a few times no problems, if i remember correctly they had a 40 amp and other sizes

kamenges · Apr 23, 2020

Check the specs on any of the power supplies you are considering. Some power supplies, like the Puls mentioned, can simply be paralleled. Others may have a switch to indicate master or slave operation. Others can't be paralleled at all.

If you are going to use diodes in series with the outputs they need to be able to handle the full current you expect to use from the power supply. In other words, they need to be big diodes. Also, you will need to make sure you get power supplies with adjustable outputs because you will need to have a 24.7V-ish output from the power supply to get a 24V usable supply. I have never actually seen this done but I would have to guess it would work.

Keith

parky · Apr 23, 2020

Can you not split your supplies ?.

Kimber45 · Apr 23, 2020

I had the same issue once. There were terminals on the power supply for just that, connecting parallel to another.

BryanG · Apr 23, 2020

As Parky says, unless you have one thing that needs 60Amps you might be better to run different parts of the circuit off different supplies. Otherwise you are having to run lots of cables capable of taking 60Amp. So long as you connect the commons you won't have issues with PLC inputs or 4-20mA circuits. Then using something like this lets you safely split the current on each supply.
https://shop.murrelektronik.com/en/...protection-4-CHANNELS-9000-41034-0100600.html

Esieli · Apr 23, 2020

I could split them up and I seem to keep getting steered that way. My only concern was if someone in the future accidentally crosses the 2 24V power supplies on accident.

Obviously that's their fault if that does happen, given I properly identify everything, but I would just sleep better knowing I made it all on 1 for them.

Thanks for the replies.

doctord · Apr 23, 2020

there are 60 amp power supplies available why not use one of them

alive15 · Apr 23, 2020

How do you maintain the voltage levels between the supplies? Don't both PS have to be equal, otherwise the higher one will always provide the current while the lower one sits back?

Saffa · Apr 23, 2020

You can definitely parallel up two or more using diodes. Power supplies that have a foldback protection mode are best.

I have used high current bridge rectifiers as the diodes.

I would get the supplies set up with no load and adjust output voltage on each supply until equal and the output of the diode bridge at 24V. Then apply load and check that each supply is providing approx even current. Readjust voltage as needed.

We have one set up like this running fine since 1995. Only 20A supplies but same principle

lfe · Apr 24, 2020

Large diodes on large heatsinks, with 60A they will dissipate at least 60W.

If it can be divided into two circuits each with a power supply I think it would be a good solution.

NetNathan · Apr 24, 2020

You can also check with the mfg to see if you can parallel the supplies. I have run into some that you can and some that you cannot.

BryanG said:
As Parky says, unless you have one thing that needs 60Amps you might be better to run different parts of the circuit off different supplies. Otherwise you are having to run lots of cables capable of taking 60Amp. So long as you connect the commons you won't have issues with PLC inputs or 4-20mA circuits. Then using something like this lets you safely split the current on each supply.
https://shop.murrelektronik.com/en/...protection-4-CHANNELS-9000-41034-0100600.html

I use this Phoenix Contact version for my 24vdc circuits, it is an 8 channel and you can easily change the setting for each channel.
https://www.phoenixcontact.com/online/portal/us/?uri=pxc-oc-itemdetail

id=2905744&library=usen&pcck=P-17-01-05-04-01&tab=1&selectedCategory=ALL

They make a 4 channel version also, but changing the setting is kind of cryptic.

BobB · Apr 25, 2020

I normally use bridge rectifiers for this. When idling one power supply may supply most of the power but when the load goes up they equalise through the bridge rectifiers.

jraef · Apr 25, 2020

What are you powering that requires 60A at 24V? That means running #6 or maybe even #4 wire, so I SERIOUSLY doubt that you have ANY 24VDC devices that can take that large of conductors. If this is for a DC motor(s), you don't want to use the typical COTS power supplies, they will usually have a "crowbar circuit" that will turn off if there is a large current surge, i.e. starting a motor. In addition, many 24VDC devices REQUIRE that the Power Source be Class 2, which is limited to 100VA, basically 4A at 24VDC.

Esieli · Apr 28, 2020

jraef said:
What are you powering that requires 60A at 24V? That means running #6 or maybe even #4 wire, so I SERIOUSLY doubt that you have ANY 24VDC devices that can take that large of conductors. If this is for a DC motor(s), you don't want to use the typical COTS power supplies, they will usually have a "crowbar circuit" that will turn off if there is a large current surge, i.e. starting a motor. In addition, many 24VDC devices REQUIRE that the Power Source be Class 2, which is limited to 100VA, basically 4A at 24VDC.

The application is a bunch of 24VDC linear actuators that pull up to 5 amps each. It's not 1 device pulling all of the power.

Thanks for the info.

Combining 24V Power Supplies to get more Amps

Esieli

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