Re: Power Consumption

Hello Chris,

Am 10.10.2020 um 01:23 schrieb Christopher J. Wager | 56K Projects <cwager@xxxxxxxxxxxxxxx>:

Couple of things mostly lower consumption related, at present I have my a single psu installed in my desk side Power5.

1) does installing and plugging in the Second PSU massively increase power consumption?

Not massively, but since every PSU has some loss (to heat), it will increase. To learn more about a precise measurement of losses (not related to IBM):

https://translate.google.de/translate?sl=de&tl=en&u=https%3A%2F%2Fkb.pocnet.net%2Fwiki%2FHP_MSA60_Leistungsaufnahme

https://translate.google.de/translate?sl=de&tl=en&u=https%3A%2F%2Fkb.pocnet.net%2Fwiki%2FHP_MSA20_Leistungsaufnahme

2) how much power do these things pull approximately at idle load.

Switched Power Supplies vary a lot in circuitry, even if basic parts stay the same: Rectifier, chopper transistor, high-frequency transformer, rectifier(s) and some kind of control loop, overload, and sometimes underload protection. Within these confines, there can be refinement against losses, enhanced stability, etc. Losses can be compensated by not using dampening resistors but more elaborated ways to recover energy from overshoots, using more circuitry to enhance the control signal of the chopper transistor, use low threshold voltage components instead of plain silicium diodes always "eating up" 0.7V, use fast-recovery diodes as secondary rectifier, use high-quality caps with low inner resistance to lessen conversion of ripple current into heat, etc. Newer designs need to adhere to regulatory specifications, being more efficient.

All in all, these are an awful lot of factors. It's hard to even make rough estimates. You can only know by measuring.

3) when the box is in the Power Off state but plugged in and the service processor running does this still draw a significant amount of power?

Yes. Measurements, I took myself (for rough comparization):

- 9117-520: ca. 30W,
- 9406-800: ca. 20W,
- 9406-S20: ca. 20W,
- 9401-150: ca. 8W.

I thought, I had measured the idle load (only a fan) of my #7116 expansion unit attached to my 800, but I can't find where I noted that down.

4) should I just flip the power switch once at Power Off state or is doing that routinely going to box my power supply.

Do it. It's not doing any harm, and you save a considerable amount of power.

This box is at home hence the opting for not being in all the time.

The 9117-520 I once had was drawing 600W from mains, with only one disk attached. It generated an awful lot of heat and noise. Too much for me to even run it occasionally.

:wq! PoC

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