Network switch on UPS damaged by utility or generator power?

[RAKocher]

Is it possible for an electrical anomaly to damage something through a good quality 120 volt uninterruptible power supply?

 

[gadfly56]

Is it possible for an electrical anomaly to damage something through a good quality 120 volt uninterruptible power supply?

It depends on the type of UPS you have. IIRC, standby uses the POCO power and switches in a couple of cycles to battery when there is a sag or blackout. Line interactive pulls from an inverter powered by the battery all the time, said battery always being charged. If you have the first it might be possible. Not with the second, I believe, unless it has some fall back that uses line power in case there is a battery or inverter failure.

 

[Little Bill]

The ones I use have a "brown or black out feature". If the voltage dips or spikes, it kicks over to battery. They warranty against damage from dips or spikes (except lightning).

 

[RAKocher]

It is of the line interactive type, very new and it's loaded to about 60% of it's 900 watt rating.
I think I need to clarify exactly what happened from the IT department.

 

[zbang]

Given the size of the UPS, the network equipment (switch/router?) probably isn't "enterprise" grade and might even be using a wall-wart power supply (which are often rated for 100-240v). This could be a simple case of infant mortality of the gear- the first anomoly that comes along causes failure.

 

[PaulMmn]

Most residential-grade UPSs have some form of surge protection built in, but that's not their primary purpose. The APC UPSs I have at home have automatic buck/boost adjustments to keep the let-through voltage at the 'normal' 120 volt level.

Look up "Zero-Surge" surge protectors. They guard my computers, TVs, and hi-fi at home. They do not use MOVs, and, as such, do not lose some of their protection with each surge.

 

[RAKocher]

Line interactive pulls from an inverter powered by the battery all the time

I noticed this partial sentence in the overview for the UPS:
"this line-interactive UPS switches to battery backup mode in milliseconds to keep your connected equipment running long enough to save files and shut down safely with no data loss."

The UPS in question is probably one of the top brands out there in this size, Its power supply is internal and I see the manufacturer does insure for damage.
I also found "White Paper 79" by Jeffrey Samstad of Schneider Electric about UPS systems below 50,000 VA, which I haven't had time to read yet.

 

[hbiss]

Is it possible for an electrical anomaly to damage something through a good quality 120 volt uninterruptible power supply?

What is the "something" and how big is the UPS? I have had equipment supplied through "one of the top brands out there" that had nothing but problems until I removed the UPS and connected it directly.

I have a problem with the statement "this line-interactive UPS switches to battery backup mode in milliseconds ".
If it were true line-interactive, it would be running off the battery all the time. The AC line just keeps the battery charged. So there should be no switching.

So, IMO, using a UPS is no guarantee that the supplied equipment won't be damaged or have problems anymore than without one.

And that $100,000 guarantee isn't worth the ink it's printed with. I've yet to hear of anybody collecting on it.

-Hal

 

[jim dungar]

I have a problem with the statement "this line-interactive UPS switches to battery backup mode in milliseconds ".
If it were true line-interactive, it would be running off the battery all the time. The AC line just keeps the battery charged. So there should be no switching

We used to call an 'always on' UPS 'double conversion'.
Line interactive units have a millisecond transfer time.

Line Interactive vs. Double Conversion UPS - Which One’s Best? - QPS

A client once purchased a line-interactive UPS system to protect their sensitive metrology units. Still, their units continued to fail from power problems. Why? Because a line-interactive system does not protect against all nine common power anomalies. Although we do sell line-interactive UPS...

www.qpsolutions.net

 

[RAKocher]

What is the "something" and how big is the UPS? I have had equipment supplied through "one of the top brands out there" that had nothing but problems until I removed the UPS and connected it directly.

They have 3 rack mounted network switches with around 100 patch cords plugged in, the UPS is rated for 900 watts and when I measured was drawing 4.5 amps at 123 volts (IDK how dynamic the load of equipment like this is, if at all).
Last Sunday morning there was a brief POCO power disruption, and generators in all buildings started.
I'm still not exactly sure what all failed and had to be replaced.

We used to call an 'always on' UPS 'double conversion'.
Line interactive units have a millisecond transfer time.

I'm learning! That's a good article, and I'm going to send it to the IT department.

 

[PaulMmn]

Don't forget a good non-MOV surge protector. Most computer centers don't really have a surge protector; I think we just have a honking big double-conversion UPS. Smaller installations using consumer-grade UPSs will need a separate surge protector.

 

[hbiss]

We used to call an 'always on' UPS 'double conversion'.
Line interactive units have a millisecond transfer time.

Line Interactive vs. Double Conversion UPS - Which One’s Best? - QPS

A client once purchased a line-interactive UPS system to protect their sensitive metrology units. Still, their units continued to fail from power problems. Why? Because a line-interactive system does not protect against all nine common power anomalies. Although we do sell line-interactive UPS...

www.qpsolutions.net

Ahh, yes. Apparently "line interactive" is really the new name for what I called the run of the mill UPS. Lowest cost. Guess they decided to call it "line interactive" to make it sound better. All is not fair in the UPS world and the people they sell to aren't rocket scientists.

The double conversion is what I thought they were talking about. Inverter runs off battery and the line just keeps the battery charged. That's why I couldn't understand them talking about switching. With double conversion there is no switching.

-Hal

 

[jim dungar]

Ahh, yes. Apparently "line interactive" is really the new name for what I called the run of the mill UPS.

Thinking back at least 35 years, I recall there were three designs.
Off-line = a noticeable outage existed before the batteries came on. Not bad when the power supplies had enough 'capacitance' to ride through utility 'blips'. Definitely the lowest cost solution.
Line interactive = automatic switching to batteries in milliseconds. Improved switching electronics made this the current preferred low cost method.
Double Conversion = Always on batteries, the gold standard in UPS design. The isolation from the power grid also provides a large amount of power quality correction.