Running other things off the PC power supply. Where do you draw the line?

[BadMouth]

I have this 430w power supply: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026&Tpk=corsair%20430
Which, going by the specs says the 12V rail can handle 28A.

It's going to be powering only:
                A 95w cpu (95w)
                2GB DDR2 (30w)
 WD black hard drive  (11w)
           Nvidia 8600GT(47w)
       Budget mobo      (50w?)
----------------------------------
                     Total     233w plus a keywiz, coin door LEDs and maybe an led marquee light.

I plan to rotate the monitor using a 12v linear actuator that has a max draw of 3.5A, but the monitor will be riding on bearings and shouldn't require much force to move, so I doubt it will ever pull that much current.  Using an online calculator, maximum possible draw comes out to 42w.

Would it be ok to power the actuator from the PC power supply, or would that be a recipe for disaster?
Should I still be leary of doing this even with a bigger power supply?

[Dervacumen]

Seems reasonable to me but I always overbuild so I'd probably go with a larger PS.  Remember the manufacturers give numbers that are lab tested under ideal conditions.  You'll see higher draw, likely.  What's the difference in cost for a larger PS?  Is it worth the PITA when you have to troubleshoot the whole system if something goes wrong?  Not trying to scare you, just think about that.

[P-chan]

Buy a 2nd cheap PC powersupply and use it strictly for the motor?  This one is $15 shipped and has decent reviews.  Small price to pay for piece of mind, IMO. 

http://www.newegg.com/Product/Product.aspx?Item=N82E16817152019

[kahlid74]

Your calculations look good so I would think you'd be fine powering it off the same PS.  The only thing I would be concerned with is how good of quality the PS is.  That actuator could produce noise that the PS can't filter and in turn could drive it back to your PC potentially damaging your components.  So I'm not worried about the PS being powerful enough to handle it, I'm more worried about what could come back through the PS to damage the computer.

[Vigo]

What, no Cuisinart and shoe buffer running off of that power supply as well? Wimp!

[lanman31337]

You should be fine.  Since no power supply is 100 percent efficient and this one is an 80+, the lowest amount of power you're looking at is around 344 watts, which is still under the numbers you're at.

[BadMouth]

Your calculations look good so I would think you'd be fine powering it off the same PS.  The only thing I would be concerned with is how good of quality the PS is.  That actuator could produce noise that the PS can't filter and in turn could drive it back to your PC potentially damaging your components.  So I'm not worried about the PS being powerful enough to handle it, I'm more worried about what could come back through the PS to damage the computer.

That's the type of thing I'm curious about.  That and if the hit of the initial draw adversly affects the power going to the pc, even if the PSU isn't undersized.

I have other power supplies laying around that I could use.
The purpose in going this route would be to have less crap and less wiring inside the cab.
If it's just a bad idea, I won't go that route.

I'm still interested in more insights from people who know more than me or might look at it from a different angle.  
Curious about the question in general.  Not just as it applies to my situation, but maybe someone running servos or other devices.

[milhouse]

I have other power supplies laying around that I could use.

If that's the case, you could always go this route.  I've thought about doing it but so far I haven't needed it. 

[kahlid74]

Your calculations look good so I would think you'd be fine powering it off the same PS.  The only thing I would be concerned with is how good of quality the PS is.  That actuator could produce noise that the PS can't filter and in turn could drive it back to your PC potentially damaging your components.  So I'm not worried about the PS being powerful enough to handle it, I'm more worried about what could come back through the PS to damage the computer.

That's the type of thing I'm curious about.  That and if the hit of the initial draw adversly affects the power going to the pc, even if the PSU isn't undersized.

I have other power supplies laying around that I could use.
The purpose in going this route would be to have less crap and less wiring inside the cab.
If it's just a bad idea, I won't go that route.

I'm still interested in more insights from people who know more than me or might look at it from a different angle.  
Curious about the question in general.  Not just as it applies to my situation, but maybe someone running servos or other devices.

I would either then utilize another PS or buy a PS specifically for motors and use that to power the actuator.

[DaOld Man]

I dont feel good about using the PC power supply for much of anything else, especially heavy inductive loads such as a motor. And as Jim suggested, you can get power supplies pretty cheap off ebay, just make sure you get one that can handle the current you will be putting on it. Some are pretty compact and wont take up a lot of room.
And if you can still find them the old AT power supplies are great for additional power, but they have a rather large footprint, if you are pressed for space.

[AlanS17]

What about using an arcade machine power supply? All of the individual voltages are already broken out and there's really no modification. Just screw down to the 12v terminals. Plus, you have all the other voltages in case you find a use for them in the future.

Did I mention I have 3 or 4 brand new arcade power supplies that I'd be willing to let go for cheap? 

[darthpaul]

I am currently up to 4 separate power supplies, one for my servos and LED lighting one for the monitor rotation motor, one for the CP rotation motor and one for my 3 actuators. Like others have said they are pretty cheap on ebay or if you have some old PCs laying around you could pull the power supplies out of them.

[TopJimmyCooks]

Due to switchcade having a small form factor pc power supply, I got a separate atx power supply for the rotation motor, marquee and cabinet fans.  $15 from newegg. 

[Vigo]

I never thought much into using the PS unit until recently when I acquired an old LCD monitor that was missing it's 12v 3a power supply. Sounds as simple as wiring a DC socket to a yellow and black wire. If I figure correctly, I wouldn't need to buy a smart strip either if I have nothing else that would plug into an AC outlet.

[BadMouth]

I am currently up to 4 separate power supplies, one for my servos and LED lighting one for the monitor rotation motor, one for the CP rotation motor and one for my 3 actuators. Like others have said they are pretty cheap on ebay or if you have some old PCs laying around you could pull the power supplies out of them.

Yeah, it's not about the money or the modding.  It's that I'd get a certain amount of satisfaction from the simplicity of running everything off a single supply. I was even looking at line filters (which would cost more than a power supply), but don't know enough about these things to be confident that the PC would be safe.

The actuator is only drawing around 1A with no weight on it, so I'll probably end up running it off a laptop block.
I'll most likely mount it to the bracket that I'm building the rotating mechanism onto.
That way, the rotating mechanism/monitor mount will be a self contained unit with just a power plug and signal plug to connect inside the cab.

I plan to sit down and carefully read your build thread before getting too far into this.  

[BadMouth]

I never thought much into using the PS unit until recently when I acquired an old LCD monitor that was missing it's 12v 3a power supply. Sounds as simple as wiring a DC socket to a yellow and black wire. If I figure correctly, I wouldn't need to buy a smart strip either if I have nothing else that would plug into an AC outlet.

I've been running a 12" touchscreen monitor off an old 250w AT power supply for a year or two and it's been fine.
(it's also running a megatouch board and IDE/compact flash drive)

[AlanS17]

I'm telling you, nothing says "authentic" like a real arcade power supply! 

[darthpaul]

I am currently up to 4 separate power supplies, one for my servos and LED lighting one for the monitor rotation motor, one for the CP rotation motor and one for my 3 actuators. Like others have said they are pretty cheap on ebay or if you have some old PCs laying around you could pull the power supplies out of them.

Yeah, it's not about the money or the modding.  It's that I'd get a certain amount of satisfaction from the simplicity of running everything off a single supply. I was even looking at line filters (which would cost more than a power supply), but don't know enough about these things to be confident that the PC would be safe.

The actuator is only drawing around 1A with no weight on it, so I'll probably end up running it off a laptop block.
I'll most likely mount it to the bracket that I'm building the rotating mechanism onto.
That way, the rotating mechanism/monitor mount will be a self contained unit with just a power plug and signal plug to connect inside the cab.

I plan to sit down and carefully read your build thread before getting too far into this.  

I hear you, I gave up on simplicity once DaOld Man talked me into automating all these things  . I think I'm just being overly cautious by using so many. It is entirely possible on my cabinet to have the 3 actuators and both rotating motors all running at the same time. I probably don't need a separate power supply for the servos but I thought it was a good idea to isolate them from everything else. I have plenty of room in my cabinet, I might as well fill it up