[j-nsp] MX10008 power supply configuration

[Vincent Bernat]

Thanks!

In the meantime, I got additional information from our SE but I have 
failed to report them here.

The switches on the PSU to select which inputs are enabled are just here 
for monitoring. If you enable both inputs and loose one, it will use the 
same amount of power on the remaining input than if it was configured 
with only a single input. The only difference is that you won't get an 
alarm.

Therefore, using 30A, you must be prepared to have 5000W on a single 
input, so around 22A (in Europe). Therefore, using 16A inputs won't 
work. If you are using 20A, the max would be 2700W on a single input, so 
around 12A.

As the PSU is "platinium", it should have around 90% efficiency at full 
load, so I would expect it should work with 3000W. But, I suppose there 
is additional margin of errors taken into account.

Another interesting info, is that if you mix 20A and 30A, you'll get 
20A. But once you switch the last 20A one to 30A, all PSU will switch to 
30A automatically. So, you can upgrade from 20A to 30A, one PSU at a time.

On 2024-03-01 16:06, Richard McGovern wrote:
> Not sure if this may help you or not.
> 
> Rich
> 
> Richard McGovern
> 
> Sr Sales Engineer, Juniper Networks
> 
> 978-618-3342
> 
> I’d rather be lucky than good, as I know I am not good
> 
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> 
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> On 2/18/24, 11:54 PM, "Mark Tinka" <mark at tinka.africa> wrote:
> 
> On 2/17/24 17:12, Vincent Bernat via juniper-nsp wrote:
> 
>  > Hey!
> 
>  >
> 
>  > I am a bit lost on how the MX10008 power supplies work. My main
> 
>  > question is how much power will be drawn if a power feed is lost?
> 
>  >
> 
>  > If we take the JNP10K-PWR-AC2 dual feed with high power (30-A)
> 
>  > setting, configured for dual feed, it can draw 5500 W. In Europe
> 
>  > (230V), I suppose it means it will draw 12A on one feed and 12A on the
> 
>  > other. This is not clearly stated.
> 
>  >
> 
>  > What happens if we lost one feed? I suppose it would fall back at 5000
> 
>  > W, so it would draw 22A on the remaining feed, but maybe it could just
> 
>  > fallback to half the power at 12A?
> 
>  >
> 
>  > If it would fallback at 5000 W, I don't understand why there are DIP
> 
>  > switches to configured mono or dual feed. We could just not plug the
> 
>  > second feed and be done with it.
> 
>  >
> 
>  > Also, on the power supply, there are these markings:
> 
>  >
> 
>  > INPUT1 OR INPUT2: PER INPUT 28.5A, 5000W MAX
> 
>  > INPUT1 AND INPUT2: PER INPUT 16A, 5500W MAX
> 
>  >
> 
>  > But again, it is unclear if the choice is done by configuring the
> 
>  > switches or if this depends on the number of actuel inputs used. If I
> 
>  > configure the DIP switches to use both input, do I still get 16A per
> 
>  > input if one feed fails?
> 
>  >
> 
>  > Ideally, when configured in high power mode, it could fallback to
> 
>  > ~3700W when on one feed, but I suppose this would marked more clearly
> 
>  > in the documentation. This would mean 33kW when full, 16.5kW when
> 
>  > loosing half the power supplies (unlikely if they are dual feed) and
> 
>  > 22kW when loosing one feed.
> 
>  >
> 
>  > Otherwise, we'll run in 20A mode, get 30kW with 6 power supplies, or
> 
>  > 15kW with half of them or 16.2kW with half of the feeds.
> 
> Sounds like the kind of question best answered by your SE.
> 
> Mark.
>