GamePro gets 360 Debug kit (power supply?)

[robofunk]

First I've finished my 3rd year of electric(al) engineering and I'm currently in Japan on an intership.

Second you are completely wrong. Say Vp is peak voltage of a sinusoidal voltage, Ip the peak sinusoidal current, Cos(X) the power factor, X is the phase difference betwen current and voltage.

P= (1/2)VpIpCos(X)
or
P=VICos(X) where V is the RMS voltage, I the RMS current.

The current and voltage given on the power brick are RMS (peak voltage for North America is around 170V). Now for the power factor, power factor is directly related to efficiency so when I say the entire power supply has 70% efficiency I don't have to take it into account.

So for 213W DC, if the efficiency is 70% then input AC power at the wall is 300W. And since I suspect they used the North American standard for voltage 110V the 2.7A number fits perfectly with the 300W number. Even at a lower efficiency like 66% the input power is 324W which would point to an equally valid voltage of 120V.

 

[randycat99]

Say Vp is peak voltage of a sinusoidal voltage, Ip the peak sinusoidal current, Cos(X) the power factor, X is the phase difference betwen current and voltage.

power factor? Are you expecting unusually high reactance imbalance in a power supply? This isn't a giant electrical motor on a factory floor.

The current and voltage given on the power brick are RMS...

This part is suspect, but if you say so, then it does make the calculations quite simple. It also makes "600 W" just as plausible as "300 W". So I guess we are at an impass.

Now for the power factor, power factor is directly related to efficiency so when I say the entire power supply has 70% efficiency I don't have to take it into account.

"Power factor" is going to be just about nill unless you have something like a giant electric motor or a huge grid of capacitors. The only thing we need be concerned about wrt "efficiency" is how much ends up as "clean" power vs. how much ends up as waste heat. Huge inductance and/or capacitance doesn't necessarily generate waste heat, but it does store energy.

And since I suspect they used the North American standard for voltage 110V the 2.7A number fits perfectly with the 300W number.

The "suspect" part makes this a shakey point, but you made your point.

 

[robofunk]

power factor? Are you expecting unusually high reactance imbalance in a power supply? This isn't a giant electrical motor on a factory floor.

This part is suspect, but if you say so, then it does make the calculations quite simple. It also makes "600 W" just as plausible as "300 W". So I guess we are at an impass.

"Power factor" is going to be just about nill unless you have something like a giant electric motor or a huge grid of capacitors. The only thing we need be concerned about wrt "efficiency" is how much ends up as "clean" power vs. how much ends up as waste heat. Huge inductance and/or capacitance doesn't necessarily generate waste heat, but it does store energy.

The "suspect" part makes this a shakey point, but you made your point.

*Sigh* Go back and look at the article I posted, power factor is of big importance in it. Not that it matters in tthis discussion, your whole point was that I was performing the calculations wrong, if power factor is of no importance that only make my calculations more valid. I think I've proved sufficiently that the Xbox 360 power supply at most uses around 300W. In normal use I would say that number is A LOT lower but at worse efficiency.

 

[PC-Engine]

Computer power supplies are typically switching power supplies, which also allows them to be quite compact. The looks of the XB360 PSU do not look particularly "compact" for 200 W of DC, hence it would be surprising to find it to be a switching design.

Have you seen a 200W 1U PSU?

 

[randycat99]

If power factor was of any substantial degree in a power supply, that would imply a serious mismatch in inductance and capacitance in the design, which would furthermore suggest it is a very poor design to begin with. The whole point of a "high-grade" PSU is to match up the capacitance to the inductance for optimum energy transfer, along with adequate filtering to reduce the ripple in the DC output as much as is cost-practical. If you got PF dropping 30% losses in a power supply, you got a serious problem. (Hint: PF is usually an issue in the "device" that is being powered, if it is an issue, rather than the thing that is making the power, i.e., a PSU)

 

[randycat99]

Have you seen a 200W 1U PSU?

Yeah, I'd say the PSU for a server rack is under considerably more stringent tolerances for stability, reliability, and power quality than a power brick for a CE device. Hefty size is to be expected, and there is no requirement to fit into a standard PC case.

 

[PC-Engine]

Yeah, I'd say the PSU for a server rack is under considerably more stringent tolerances for stability, reliability, and power quality than a power brick for a CE device. Hefty size is to be expected, and there is no requirement to fit into a standard PC case.

A 200W 1U PSU isn't large at all but it isn't small like laptop bricks either. In fact it occupies about the same volume as that Xbox 360 brick. I don't see why it couldn't be a switching PSU from just looking at the size.

 

[randycat99]

"Large" compared to what? ...compared to a 400-500 W PSU that goes in a standard PC case? That was the context you took my remark out of, and you bring server equipment into the mix just to make a point? Gimme a friggin break! I don't know if you are trying to imply the X360 PSU comes from a server design or what, but assuredly it is quite closer in design standards to what goes in a consumer PC than server gear. In that respect, it is large for the power output. Case closed.

 

[robofunk]

There's probably any number of reasons why it's so big. Remember the power cord recall the Xbox had, bet MS doesn't want that to happen again.

 

[randycat99]

...not to mention it just might not be the fanciest switching design from the computer realm. It's not good or bad either way. Just trying to put things in perspective, here, given the information we have available.

 

[PC-Engine]

In that respect, it is large for the power output. Case closed.

The PSU for GCN seems large for it's power output too, but when you actually open it up most of it is empty space.

 

[Ty]

The PSU for GCN seems large for it's power output too, but when you actually open it up most of it is empty space.

There must be a reason WHY they intentionally make it so large. What does the extra space give them?

 

[PC-Engine]

There must be a reason WHY they intentionally make it so large. What does the extra space give them?

I'm guessing a couple of reasons both of which fall under safety. With a big shell, it's less of a fire hazard because the large shell creates a distance isolating it from the actual hot components of the PSU. The other reason is to prevent burns from people touching the PSU. A laptop brick gets pretty darn hot to the touch due to the hot components fitting snugly against the brick shell.

 

[rabidrabbit]

I got an idea that MS marketing people should consider.
They could label the power supply PS360, so when people open the xbox360 box and see the power supply with the xbox, the first impression would be that they've got two consoles for the price of one, and xbox plus a new PlayStation!!
It's the first impression that counts

 

[one]

From the UK retail package -
http://forum.teamxbox.com/showthread.php?t=387765

 

[ps2xboxcube]

Giant AC Adapter Confirmed for Retail Xbox 360

According to Famitsu, the Xbox 360's AC adaptor is the largest of any game console, with a length of 210 mm, width of 75 mm and height of 54 mm. The Japanese game magazine obtained an advance shipment of a limited edition Xbox 360 launch pack (retail approx $336), which included the console, a LAN cable, a D-terminal video cable, AC adapter, 20GB HD, Xbox 360 remote control, one wireless controller and a limited edition headset.
The adapter itself is roughly 85 percent in volume of the slim PS2 (850.5 cubic centimeters versus 978.9 cubic centimeters)--easily surpassing the size of the current-gen Xbox adapter.

According to Microsoft, the larger adapter is due to the higher electrical power consumption of the Xbox 360. The max power consumption of Microsoft's next-gen console is 254 watts--notably higher than the 200 watts for the Xbox and dwarfing the 45 watts for the PlayStation 2.

"The Xbox 360 has a triple-core CPU and an ATI graphics processor CPU--to have this running it requires a lot of power," Microsoft told Famitsu.

Interestingly, the adaptor purportedly has two fans inside, too. While Microsoft has yet to give official word on the final retail adapter for the North American version, the chances are high that the stateside Xbox 360 will also have a hefty AC adapter as well.

http://gamepro.com/microsoft/xbox360/games/news/49646.shtml

 

[Guden Oden]

Giant AC Adapter Confirmed for Retail Xbox 360

Ok, so it is a GIANT AC adapter... So what. In this case I'm kind of like, if it can't be installed internally, better make it big and bold than small and puny. I'd really hate it if my adapter is smaller when I get my x360 than I was led to believe from all the internet hubub...

Besides, that gamespot article is erroneous in commenting that the x360 adapter 'easily dwarfs' (or such) the original xbox's, as the original box didn't have an external adapter.

 

[randycat99]

I'm kinda amazed that the original Xbox is cited at 200 W (makes me really suspect that someone is mistaking the distinction between "input" and "output" power specs when reading the power rating labels on a device). Going from 200 to 250 W in the X360 really isn't that much of a jump in power draw, imo.

 

[Guden Oden]

The original box is of course not anywhere near 200W power dissipation... 250-ish W for x360 however is a lot more believable, considering the cooling measures taken (dual 80mm fans on the back, lots of vent holes, internal ducting etc).

 

[randycat99]

Yes, I agree, and that is why I believe the "200 W" spec for Xbox doesn't add up. Now if it were really "100 W of DC power", that would seem to make sense that the prowess of X360 drawing 250 W is considerably more than the XBox.