2N UPS Redundancy sync needed?

[Anonymous user]

Hi,

i'm building a new little DC on new office.

The DC will host 8 servers with dual PSU and 4/6 Switch with mono PSU.

I'd like get 2N redundancy with 2x 10KW UPS with this configurations:

ATS AP4421 haas dual input power and output for mono PSU device, as network switch.

PDU APC AP8858 is for each PSU Server power.

This configuration is ok, or it's need power sync or other device?

How load is distributed on each UPS?

Thanks

[Anonymous user]

Hi 

You need not require separate sync for above scenario, ATS will have an option of selecting preferred source and load would be connected on the preferred source. ATS by default has window of tolerance for seamless transfer from preferred source to redundant source in case of failure, please do refer the enclosed product data sheet of AP4421

https://download.schneider-electric.com/files?p_File_Name=BSTY-AQSJFY_R0_EN.pdf&p_Doc_Ref=SPD_BSTY-A...  

[Anonymous user]

Hi, thank you for answare, but i refer to UPS-PDU-Server_PSU Configuration.

i'm asking

- if attaching each Server PSU on separate UPS is correct or i'm need for a sync devic

- how the load is distributed: half for each UPS, only one UPS or full on all UPS?

Thanks

[Shaun]

Hi,

Ultimately this is up to the end device so to be absolutely sure you'd want to address this with the equipment vendor.

I've only used Dell & HP servers, and they've both spread the load across both power supplies.  I've never had any syncing issues, I strongly suspect the DC outputs from the PSUs are combined, so the two AC legs operate entirely independently.

The main thing to be aware of in this configuration is that the regular load on the UPS will only be half of the potential load.  So if you have two UPSes loaded at 60%, and one UPS needs to be taken out of service (or has a fault, or exhausts its runtime before the other), the remaining UPS will now be at 120%, and your day will get worse.

(As noted the ATS behaves the opposite of this - the unused input is treated as a cold spare so 100% of its load will be on one leg or the other, never both)