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Old Jul 27, 2010, 01:08 AM
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i still have not heard back from anybody regarding using one of these for running a quad indoors for testing/trimming w/ a ~30' extension cord. i have read i would need capacitors but don't know where. fwiw, the quad should hover @ ~15A or so and indoors bursts of maybe 45A at the max.

any assistance w/ this area would be greatly appreciated,
tia,
bob
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Old Jul 27, 2010, 01:24 AM
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Son, Norway
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Originally Posted by indyrcpilot View Post
My power supply didn't come with a cord of any kind. Looking at the label, it appears that it should work on 120V. Normally there is a switch near the plug to go from one to the other. Hopefully the supply will be smart enough to figure it out.
Switching supplies often handles both voltage ranges automatically. Note that max power might be lower when run on 120V.

Fred
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Old Jul 27, 2010, 01:28 AM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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From post#3

The supply is rated on the case at 106A @ 12V on a 200-240Volt supply and 74A on a 100-127V one

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Originally Posted by flarssen View Post
Switching supplies often handles both voltage ranges automatically. Note that max power might be lower when run on 120V.

Fred
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Old Jul 27, 2010, 03:05 AM
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Sydney, NSW, Australia
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Originally Posted by linw View Post
Does yours just have a tiny fan?
As far as I can tell, mine looks physically identical to yours. They really seem to be the duck's guts - small, quiet, cheap, and pack a huge punch. Can a 12V supply get any better than the CS HE?
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Old Jul 27, 2010, 05:46 AM
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Originally Posted by Keithf View Post
As far as I can tell, mine looks physically identical to yours. They really seem to be the duck's guts - small, quiet, cheap, and pack a huge punch. Can a 12V supply get any better than the CS HE?
What can I say, Keith, seeing as we have similar items!! And I have three! Thought I'd sell at least one but I dunno, now. Two for 24V in the future and one spare?? They just seem too nice to move them on!

Cheers,

Lindsay.
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Old Jul 28, 2010, 01:17 AM
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The fan in my Dell PowerEdge 2850 powers is quite noisy. The PSU will shut down without a spinning fan. I tried 3 diodes in series with the fan. It worked, but still a bit noisy. Yesterday I tried connecting the fan to the 3.3V section of the PSU and it was spinning slowly but the PSU was still happy. I tried some load test at 48A for several minutes. No problem, but the small amount of air that the fan pushed through was quite warm, so some more RPM is probably needed. I realise the best option would be regulation by temperature.
Anybody know where to get "noise killers" that doesn't shut the fan off completely?

Fred
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Old Jul 28, 2010, 01:28 AM
ancora imparo
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Melbourne, Australia
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How about a 5V 3 terminal 3A regulator? Pretty cheap and simple to use. Might need a small cap across the output for stability? Think the fan will spin a lot faster than it did on 3.3v since that must be just about it's startup voltage.

Quote:
Originally Posted by flarssen View Post
The fan in my Dell PowerEdge 2650 powers is quite noisy. The PSU will shut down without a spinning fan. I tried 3 diodes in series with the fan. It worked, but still a bit noisy. Yesterday I tried connecting the fan to the 3.3V section of the PSU and it was spinning slowly but the PSU was still happy. I tried some load test at 48A for several minutes. No problem, but the small amount of air that the fan pushed through was quite warm, so some more RPM is probably needed. I realise the best option would be regulation by temperature.
Anybody know where to get "noise killers" that doesn't shut the fan off completely?

Fred
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Old Jul 28, 2010, 02:18 AM
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Originally Posted by jj604 View Post
How about a 5V 3 terminal 3A regulator? Pretty cheap and simple to use. Might need a small cap across the output for stability? Think the fan will spin a lot faster than it did on 3.3v since that must be just about it's startup voltage.
Yes, that's my plan B. The speed at 5V seems to be OK. It already get ~5.5V in the state where only 3.3V is turned on. As soon as the second jumper is attached, and the 12V part turns on, the fan voltage goes up to 12V. Too bad there is no 5V part in these, but I have many of these 5V regulators. Might pick some small ones from smoked ESC's . The plan is to run three of these in series for 12/24/36V.
Temperature regulation would be better, but I guess these PSU's will shut down also if overheated. A lot of logic in these server PSU's. Almost like computers inside computers .

Fred
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Old Jul 28, 2010, 03:56 AM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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You can buy a temp control unit for PC's that has 5 little temp sensors, 5 independent fan controls and a panel with an LCD display and alarms that might be worth it. The overclocking crowd use them. If you are building a 3x supply and concerned about heating could be useful? I'll see if I can find a picture.

OK Here's the link

http://www.nzxt.com/new/products/fan_control/sentry_lxe

Very sexy display and it's cordless. Not super cheap but the bling, the bling!


They are indeed almost computers except that they suffer from the Smoke Screen of Death rather than the Blue Screen of Death.

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Originally Posted by flarssen View Post
Temperature regulation would be better, but I guess these PSU's will shut down also if overheated. A lot of logic in these server PSU's. Almost like computers inside computers .

Fred
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Old Jul 28, 2010, 04:39 AM
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I calmed my PS4060 down by adding a 10W resistor (6.8 ohm from memory) in series with the 12V fan feed. Still shoves quite a bit of air through but much quieter than before.
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Old Jul 28, 2010, 05:03 AM
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Originally Posted by bob4432 View Post
i still have not heard back from anybody regarding using one of these for running a quad indoors for testing/trimming w/ a ~30' extension cord. i have read i would need capacitors but don't know where. fwiw, the quad should hover @ ~15A or so and indoors bursts of maybe 45A at the max.

any assistance w/ this area would be greatly appreciated,
tia,
bob
Bob,

Your problem is obviously volt drop which would be:-

30ft(x2) of 12AWG wire would drop 4.4V@ 45A and 1.4V @15A.

12AWG is already heavy (and expensive) so it would be better to try and use the PSU remote sensing facility to try to hold the voltage at the load point. This requires two more light sensing wires to be run in parallel with the main power leads and connected to their respective power leads at the load point. This is where you should add any extra capacitance to maintain AC stability. We must assume that the PSU is capable of delivering up 12V + 4.3V at its output terminals at 45A. As it is a SMPS then this is very likely.
You could use thinner power wire but it is doubtful that the PSU would be capable of the extra voltage increase.
If you do the above, be careful to run the two remote sensing leads close together as a pair (use thin twin cable) otherwise a Pi network is formed which might cause uncontrolled oscillation.
Could you not substitute a smaller psu, as light as possible for the normal Lipo in the aircraft and feed it with a 30' light mains cable?
It may well be that you are stuck either way with the weight of the heavy 12AWG cable or the lighter psu making the whole thing impractical. I don't know how big an aircraft we are talking about, but if it hovers on 12V @ 15A it can't be that large, and nowhere near large enough to lift the cable or psu.
On reflection I think that the last paragraph is the only one worth taking note of. I don't think it is practical but will leave the above as an explanation

Wayne
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Old Jul 28, 2010, 12:20 PM
Use the 4S Luke
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USA, TX, Euless
Joined Aug 2003
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Hey bob4432 - How about using some smallish batteries on board the copter to handle the surges so you can use smaller, lighter wire? You'd probably still need the caps for ripple.
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Old Jul 28, 2010, 08:07 PM
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Quote:
Originally Posted by Wayne Giles View Post
Bob,

Your problem is obviously volt drop which would be:-

30ft(x2) of 12AWG wire would drop 4.4V@ 45A and 1.4V @15A.

12AWG is already heavy (and expensive) so it would be better to try and use the PSU remote sensing facility to try to hold the voltage at the load point. This requires two more light sensing wires to be run in parallel with the main power leads and connected to their respective power leads at the load point. This is where you should add any extra capacitance to maintain AC stability. We must assume that the PSU is capable of delivering up 12V + 4.3V at its output terminals at 45A. As it is a SMPS then this is very likely.
You could use thinner power wire but it is doubtful that the PSU would be capable of the extra voltage increase.
If you do the above, be careful to run the two remote sensing leads close together as a pair (use thin twin cable) otherwise a Pi network is formed which might cause uncontrolled oscillation.
Could you not substitute a smaller psu, as light as possible for the normal Lipo in the aircraft and feed it with a 30' light mains cable?
It may well be that you are stuck either way with the weight of the heavy 12AWG cable or the lighter psu making the whole thing impractical. I don't know how big an aircraft we are talking about, but if it hovers on 12V @ 15A it can't be that large, and nowhere near large enough to lift the cable or psu.
On reflection I think that the last paragraph is the only one worth taking note of. I don't think it is practical but will leave the above as an explanation

Wayne
i put 30' up, but it wouldn't all be lifted, probably only 4-10' vertical the more i think about it, w/ 10' being an extreme max, probably more like 6'. i was just thinking 30' so there is more than enough cable to actually fly the quad a bit inside - say in a 10' cube area or so.

i could shorten the cable to say 15' so that way i could still fly around a bit in my living room - again, this is for testing different setups and trimming and not needing to worry about lipos and charging during the initial setup.

if i did 15' would that change much? does the voltage drop go linear or exponential?

tia,
bob
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Old Jul 28, 2010, 08:08 PM
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Originally Posted by feathermerchant View Post
Hey bob4432 - How about using some smallish batteries on board the copter to handle the surges so you can use smaller, lighter wire? You'd probably still need the caps for ripple.
how could this be done? kind of like charging as it flew?
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Old Jul 28, 2010, 09:44 PM
Use the 4S Luke
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USA, TX, Euless
Joined Aug 2003
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Yup. For instance if you hav a 12V supply use 3S LiPo. Just don't go past 12.6V

As far as voltage drop for 15ft vs 30 ft. It would be half. It's linear.
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