Understand PSU spec

[WombatWong]

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?

[Kleinstein]

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.

[T3sl4co1l]

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

[grifftech]

the 8.5 amp max input could be when first plugged in

[T3sl4co1l]

Likely inrush is much more, compliant with whatever standard (if any) applies.  Probably under 100A peak.

Tim