Distinct Voltages on Switch Redundant Power Supply

Yes, I see a problem here.

What we have here is a failure to communicate.

This redundantly powered switch is designed and intended to be sourced from multiple power sources. There are many ways this can be done safely but I'm very certain this can be done poorly. What I am certain of is that you've not communicated to us (and probably your supplier) enough information to say if this is an acceptable configuration. For instance, if your 60 HZ 120 VAC (notice I've already added unknown information) power is derived from the 220 VAC source then redundancy is lost for loosing 220 VAC will cause 120 VAC to also be lost.

My apologies, indeed I missed some info here.

Both supplies are 60 Hz. Both supplies are derived from different UPS.

The 127 V supply come from a 20 kVA Tri(input)-Mono(output) UPS, which only deliver 127 V on it's output.

The 220 V supply come from a 3 kVA Mono/Biphasic UPS, which only deliver 220 V on it's output.

Both UPS are energized from distinct Circuit Boards.

I would...

Check with both UPS manufacturers to ascertain if the UPS output neutrals are bonded to the case bond of the UPS (they should be but you never know).

Ask the UPS manufacturers if it is ok with them to bond the output neutral of one UPS to the output neutral of another UPS.

Ask the manufacturer of the switch if the neutrals of the redundant AC sources need to be tied together or not (they may be tied together inside the switch).

Then do what is indicated by the results of these questions.

The switch may not care if the redundant source neutrals are common at all, but it may matter to the switches in a big way. Ground loops can cause all sorts of nasty effects on such equipment.

Since most of us don't have schematics or documentation for a H3C S7506E Switch there is little chance that anyone will be able to answer you question. Those people who have knowledge of what this switch looks like or how it is intended to work could only take a guess about what your electrician has done.

In general, however, if the device switches between sources of power, like an A-B switch then disaster should be expected. If it fails to destroy everything connected to it, and runs everything "normally" then you are potentially loading down the 220 VAC source until its actual voltage is pulled down by the load. That places the strain on that source which is likely to be overloaded. On the other hand, if any of the substantial devices (that are operating on this pulled down voltage source) switch off then the rest of the devices will be exposed to a higher than rated voltage source and smoke will rise.

The other thing that you should understand is that the term "Redundant Power Supply" is usually associated with DC power. It provides DC power from other DC power supplies and consists of wire terminals and a couple of high power diodes.

The H3C S7506E Switch appears to be an Ethernet switch which may have redundant DC power supply inputs, but that is not what you said and I'm not going to guess.

If you are using AC to DC converters fed from different sources then say so. If there are redundant inputs for DC power, then tell us that as well. Otherwise it sounds like you are foolishly connecting twice the normal operating voltage to something and seeing no ill effects which is highly unlikely. Consider a class in creative writing where details are important.

From all the information I gathered via telephone support and from their available data sheets (https://h20566.www2.hpe.com/hpsc/doc/public/display?sp4ts.oid=4177519&docLocale=en_US&docId=emr_na-c03913361), I get the following information:

From telephone: "It won't matter if I connect different voltages AC Supplies (within the 100-240V range), as the switch will convert it to DC power inside it"

From data sheets: "Q. Can DC power supplies and AC power supplies be used on the same switch? A. No. DC power supplies and AC power supplies cannot be used on the same switch."

"The switch power supplies adopt the following protective measures:
• Input protection—Input over-voltage protection, input under-voltage protection, and input over-current protection.
• Output protection—Output over-voltage protection, output over-current protection, output short-circuit protection, and output over-temperature protection."

"• A chassis must be configured with at least one power supply. To improve power supply availability, you can configure a chassis with two power supplies, which back up each other.
• The power supplies installed on an HP 7500 switch must be the same model."

"Q. How is the intelligent power management function implemented? A. When the switch starts up, the total power that can be provided by all power supplies is calculated. Then the power required by fans and MPUs is deducted from the total power. The remaining power is used for LPUs. When a new LPU is added, the switch compares the remaining power to the power required by the LPU. If the remaining power is sufficient, the device provides power to the LPU. Otherwise, the device does not provide power to the LPU. "

This model has this 2 650W AC Power Source and has a tag "~100-240V;50/60Hz;16A" like below (right one is unplugged):

We don't have a DC supply here, only that AC.

I asked TI guys to check the "display power" command on the both 220 V supplies switch and the mixed 127 and 220 V one, and all of them are saying "Normal" for all supplies.

Unfortunately I couldn't get more info from the brazilian HP support, as many things they were unaware and couldn't redirect me to the international support also.

I'm not sure whether the default internal power supplies protection could handle the possible problems raised on the topic. I will try to contact HPE international support to check about it. Thanks for the help.

Very good follow up. Your quest for knowledge has been satisfied! And now, so that we are all clear on the subject; nearly all of the electronic equipment that has anything to do with communication, computers, amplifiers, and so on.....run on DC power. They all derive that energy from AC power. The level needed for the electronics must be smooth and well regulated (not changing) and any excess voltage is eliminated by converting it to heat.

AC power is used for transmission of energy, it can be easily converted from one voltage to another using transformers or in the case of switching power supplies, it can be converted into DC power with minimal losses in the form of heat. A UPS (uninterruptable power supply) converts AC into DC so that it can be stored in batteries, and then re-creates the AC waveform to send it back out to other equipment that converts it into DC power before it is finally used. The purpose of the UPS is to keep equipment running smoothly even if the AC power drops down or out completely. When the AC power is restored the UPS switches back to bypass mode and recharges its batteries.

If you purchase a "Redundant Power Supply" in some catalogs you will find it to be incapable of doing anything with AC power. The term can cause confusion because it implies something completely different. The Redundant Power Supply module, of which I have more than 135 in use in my facility simply routes DC power to electronics that they support with a Primary DC feed and it has a Secondary DC feed in case the Primary power supply fails. The guts inside this device consists of diodes and some LED circuits to let me know if everything if working properly.

The only reason I am going into this detail is because the term implies something other than what one might expect. In the instance I just discussed, the Redundant Power Supply does nothing to create DC power. It just directs the flow.