MS and MX PSU Output Hold-up Time

[Kane]

Hi Team,

I’m looking for the power supply minimum output hold-up time for some Meraki devices (MS and MX).

The customer is using UPS Interactive Line and the time to switch power from generator and UPS is about 6-10 ms so we want to know if the Meraki devices will restart or not.

Thank you!

Best Regards,
Kane

[PhilipDAth]

I don't know thw answer.

That is about 1/4 to 1/2 wave.  I would think you should be ok with that.

[Kane]

Thanks @PhilipDAth though!

I was hoping to provide a confirmed answer along with a documentation as well. I'm also concerned if the device's load is also a factor.

Hopefully someone from Meraki can help answer this.

[PhilipDAth]

There is no such information published.

The only way to get assurance if this is very important will be to change to a double online interactive UPS.  Plus it will provide the equipment with much more protection during the generator startup.

[PhilipDAth]

Found something interesting.  Several of the MS's support using an RPS2300 for redundant power.  It specifies the hold up time that it offers in the event of primary power supply failure.

https://www.cisco.com/c/en/us/products/collateral/switches/redundant-power-system-2300/product_data_... 

Table 2.       Power Supply Specifications

Description	Specification
C3K-PWR-1150WAC	C3K-PWR-750WAC
Maximum output power	1150W	750W
Input-voltage range and frequency	115-240 VAC, 50-60 Hz	100-240 VAC, 50-60 Hz
Input current	12-6A	10-5A
Output ratings	12V@25A and -52V@16.4A	12V@25A and -52V@8.7A
Output holdup time	20 ms minimum	20 ms minimum
Power-supply input receptacles	IEC 320-C13 (IEC60320-C13)	IEC 320-C13 (IEC60320-C13)
Power cord rating	15A	15A
LED indicators	“AC OK” - Input power to the power supply is working properly “PS OK” - Output power from the power supply is working properly

[Kane]

I'm aware of those information for the RPS 2300. However, this is only applicable if the customer is using RPS 2300 on their MS switches as backup power.

Thanks @PhilipDAth for your help though! 🙂