Author Topic: Understand PSU spec  (Read 487 times)

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Offline WombatWong

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Understand PSU spec
« on: October 12, 2018, 08:46:57 am »
Hi All,

I like to understand the PSU specification. Reference to a Meanwell power supply HRP-600-24. The AC input is 100-240VAC 8.5A 50/60Hz. DC output is 24V, 27A.

This is a 600W PSU, based on DC 24V*27A, I got around 600W. However, I do not understand 100-240VAC 8.5A can get 600W.

Can anyone explain to me?
 

Offline Kleinstein

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Re: Understand PSU spec
« Reply #1 on: October 12, 2018, 08:57:58 am »
The 8.5 A rating is the maximum input current, mainly intended for choosing fuses and lines and switches. It is kind of worst case and thus applies to the 100 V. With a 230 line voltage the actual input current would be lower.  There is also a limited efficiency and power factor, so that the current  times voltage at the input side would be higher than the output side power. So of to 850 VA in for some 648 W (24 V*27 A)  out sounds plausible.
 

Offline T3sl4co1l

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Re: Understand PSU spec
« Reply #2 on: October 12, 2018, 09:50:32 am »
Yeah, 850VA input is quite reasonable.  It has PFC, so it's not drawing, say, 1.2kVA for 600W, which is quite nice!

It may be that it's rated for 600W, but goes up to ~800W (plus losses) when operated near or beyond current limiting conditions, at certain input voltages.  It is probably not 2kVA (at 240V), but if it is, that would be important just to be sure that, in case it needs it, you can deliver it safely.

Input current rating is only a maximum figure, for wiring and fusing purposes.  It is not indicative of actual operating current or power draw.

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 

Offline grifftech

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Re: Understand PSU spec
« Reply #3 on: October 12, 2018, 02:03:29 pm »
the 8.5 amp max input could be when first plugged in
 

Offline T3sl4co1l

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Re: Understand PSU spec
« Reply #4 on: October 13, 2018, 02:34:52 am »
Likely inrush is much more, compliant with whatever standard (if any) applies.  Probably under 100A peak.

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 


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