1. Do not share user accounts! Any account that is shared by another person will be blocked and closed. This means: we will close not only the account that is shared, but also the main account of the user who uses another person's account. We have the ability to detect account sharing, so please do not try to cheat the system. This action will take place on 04/18/2023. Read all forum rules.
    Dismiss Notice
  2. For downloading SimTools plugins you need a Download Package. Get it with virtual coins that you receive for forum activity or Buy Download Package - We have a zero Spam tolerance so read our forum rules first.

    Buy Now a Download Plan!
  3. Do not try to cheat our system and do not post an unnecessary amount of useless posts only to earn credits here. We have a zero spam tolerance policy and this will cause a ban of your user account. Otherwise we wish you a pleasant stay here! Read the forum rules
  4. We have a few rules which you need to read and accept before posting anything here! Following these rules will keep the forum clean and your stay pleasant. Do not follow these rules can lead to permanent exclusion from this website: Read the forum rules.
    Are you a company? Read our company rules

Wiring server PSUs in parallel

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by benj, Jan 27, 2015.

  1. benj

    benj Member

    Joined:
    Oct 22, 2014
    Messages:
    51
    Location:
    UK
    Balance:
    44Coins
    Ratings:
    +42 / 1 / -1
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform
    Hi guys and gals,

    I've been really enjoying my motion sim and it's holding up well considering how low-tech the job was :)

    I thought it was time to upgrade from a car battery to a server PSU, and I found a bunch of Dell Poweredge 2950 units really cheap.

    They are 750W. My rig is going to be pulling 1440W, and I use a Sabretooth 2x60, with 1 12V input, so I need to wire these suckers in parallel.

    I see these 2950s have a current share pin, but I can't find much info about doing this parallel wiring properly. Can anyone offer any advice before I give it a go and blow myself up o_O:D

    Here is a picture showing my thoughts....as it says - DO NOT COPY THIS! It's most probably wrong!

    The questions I have are

    1) The current share pin A2, do they just simpy connect togther between PSUs?
    2) Can I just use 2 standard plugs, or do I need to modify them to remove/share a GND?
    3) The 'logic return' pins are GND, I use B1. Do I need 1 common GND pin between PSUs, or can I just the individual ones? ie, in the setup below I connect PSU1 A1 to B1 and PSU2 A1 to B1 - but should I connect PSU1 A1 and PSU2 A1 to PSU B1?

    [​IMG]

    Thanks everyone.
    Ben
  2. Kirk

    Kirk Member

    Joined:
    May 19, 2014
    Messages:
    91
    Occupation:
    Sr Software Engineer
    Location:
    Texas
    Balance:
    15,087Coins
    Ratings:
    +114 / 2 / -0
    My Motion Simulator:
    2DOF, DC motor
    NEVER remove the A/C ground.

    For parallel, you should be fine as you illustrated.

    For serial (24V), you want to lift the DC ground on one of the supplies, not the A/C ground (doing so can result in a very bad day).

    Also worth noting, while the server PSUs are awesome, the huge benefit over batteries is size (batteries are huge) and maintenance (batteries outgas hydrogen and need to be regularly checked for fluid levels, while server PSUs are pretty much plug-it-in-and-forget-about-it-except-the-frik-n-noise).

    If you really are bumping up against the current that a single PSU can provide, it's hard to ignore batteries as a way to augment over a second PSU, as that second PSU adds even more noise.

    I have two, but that's for 24V. I am seriously considering batteries, if for no other reason that the intermittent spikes against my household wiring. Batteries trickle charge, so at most a couple hundred watts of A/C power doesn't potentially trip my breaker and shut down my computer...
    • Informative Informative x 2
  3. benj

    benj Member

    Joined:
    Oct 22, 2014
    Messages:
    51
    Location:
    UK
    Balance:
    44Coins
    Ratings:
    +42 / 1 / -1
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform
    Hi @Kirk , great reply - thank you.

    Yes the frik'n' noise is surprising! These Dell PSUs let you adjust the fan speed, so I'll play around with that and find a balance.

    My 12volt car battery has been great, can't fault it really, I just wanted my sim to feel more 'complete' and be a bit more transportable / fool proof.
    • Like Like x 1
  4. Nick Moxley

    Nick Moxley Well-Known Member

    Joined:
    Dec 13, 2013
    Messages:
    2,779
    Occupation:
    Owner/Operator- Moxleys Rantals
    Location:
    Winnipeg Manitoba Canada
    Balance:
    17,054Coins
    Ratings:
    +2,504 / 30 / -2
    My Motion Simulator:
    2DOF, 3DOF, DC motor, JRK
    I would personally check on Rcgroups before plugging ANY thing in, They are BY far the guru's of the Server modding community and will most likely know if your going to blow the shit up or not.
    • Agree Agree x 2
    • Informative Informative x 1
    • Useful Useful x 1
  5. benj

    benj Member

    Joined:
    Oct 22, 2014
    Messages:
    51
    Location:
    UK
    Balance:
    44Coins
    Ratings:
    +42 / 1 / -1
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform
    Cheers @Nick Moxley , I will certainly dig around and post over there, thanks.
  6. benj

    benj Member

    Joined:
    Oct 22, 2014
    Messages:
    51
    Location:
    UK
    Balance:
    44Coins
    Ratings:
    +42 / 1 / -1
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform
    • Funny Funny x 1
  7. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,461
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    144,602Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
    [​IMG]
    • Funny Funny x 1
    • Winner Winner x 1
    • Friendly Friendly x 1
  8. benj

    benj Member

    Joined:
    Oct 22, 2014
    Messages:
    51
    Location:
    UK
    Balance:
    44Coins
    Ratings:
    +42 / 1 / -1
    My Motion Simulator:
    2DOF, DC motor, Arduino, Motion platform
    Good news. I wired this all up last night and nothing went bang :thumbs

    I ran my rig for a couple of hours using Dirt 3, No Limits and Burnout, and keeping a close eye on those PSUs and wiring in case of any smoke or melting...

    Everything is running fine, and amazingly well. Almost too well. The rig now has about 2x more torque than the 12v car battery :cool: So I'll have to redo all my profiles - or just keep it like this but it's a bit like 'insane mode' especially on hard crashes in Burnout!!

    Highly recommended upgrade. £15 per PSU, plug and play, no more battery charging, more torque = winner :grin:thumbs
    • Winner Winner x 1
    • Useful Useful x 1
  9. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

    Joined:
    Jul 13, 2014
    Messages:
    20,461
    Occupation:
    Innovative tech specialist for NGOs
    Location:
    St Helens, Tasmania, Australia
    Balance:
    144,602Coins
    Ratings:
    +10,741 / 52 / -2
    My Motion Simulator:
    3DOF, DC motor, JRK
  10. GTexas

    GTexas New Member

    Joined:
    Mar 14, 2017
    Messages:
    26
    Location:
    Houston, TX
    Balance:
    475Coins
    Ratings:
    +8 / 0 / -0
    My Motion Simulator:
    2DOF, DC motor, Arduino
    I fully second to never remove the AC ground. Unfortunately there are a number of posts on the web who show this as an option when connecting to supplies in series. Floating the DC ground on one of the supplies can be easily done with nylon washers / insulators for mounting power transistors to insulate the whole PCB from the casing.
  11. Oz_gadget

    Oz_gadget New Member

    Joined:
    Oct 18, 2019
    Messages:
    16
    Occupation:
    retired
    Location:
    Melbourne, Australia
    Balance:
    243Coins
    Ratings:
    +4 / 0 / -0
    My Motion Simulator:
    Arduino, Joyrider, Motion platform, 6DOF
    I spent ~20 years in IT support & many hours/days/weeks/months in windowless server rooms, may as well have been sitting in a dungeon...

    anyhoo, I can vouch for the noise, especially no the Dell & IBM PSU's, on most all (but the oldest architecture) servers they are normally hot swappable, allowing you to remove a dead PSU (as long as you had redundant PSU's) & replace it.

    We used to perform failover testing on our sandpit environment (also in a large server room) prior to commissioning boxes, & it is amazing that in amongst all that ambient noise of hundreds of other servers PSU's screaming away, when you pull 1x PSU out of a server, the second ones fan kicks in with a vengeance, normally requiring a courious glance to ensure the server rack wasn't taking off...
    Last edited: Nov 30, 2022
  12. Oz_gadget

    Oz_gadget New Member

    Joined:
    Oct 18, 2019
    Messages:
    16
    Occupation:
    retired
    Location:
    Melbourne, Australia
    Balance:
    243Coins
    Ratings:
    +4 / 0 / -0
    My Motion Simulator:
    Arduino, Joyrider, Motion platform, 6DOF
    Question : has anyone wired 2x 12V server PSU's in series to get a 24V unit?
    (or is this query worthy of another thread?)

    I'm looking at doing that to support 3x 24vdc wheelchair motors for my (bergison) integrated motion g-seat project
    Screen Shot 11-28-22 at 04.58 PM.PNG

    I followed the links here & discovered some people doing it for RC activities
    http://www.tjinguytech.com/my-projects/diy-24v-47a
    http://www.tjinguytech.com/my-projects/server-ps

    obviously very concious of mod being potentially lethal...
    gadget_sparks.gif
    so I intend to have it enclosed in its only plastic enclosure, as well as wiring up e-stop to a relay switch as illustrated.

    upload_2022-11-30_11-57-29.png

    Im hoping i can string together a temporary solution until i can afford a meanwell UHP-1000-24....
    cheers
    Last edited: Nov 30, 2022
  13. Oz_gadget

    Oz_gadget New Member

    Joined:
    Oct 18, 2019
    Messages:
    16
    Occupation:
    retired
    Location:
    Melbourne, Australia
    Balance:
    243Coins
    Ratings:
    +4 / 0 / -0
    My Motion Simulator:
    Arduino, Joyrider, Motion platform, 6DOF
    working on a acrylic shroud to keep fingers out & sparks in...

    Attached Files: