Welcome to the new Schneider Electric Community

It's your place to connect with experts and peers, get continuous support, and share knowledge.

You may be familiar with Communities' brand new layout from SE.com.
Don't forget to update your bookmarks and saved links with our new address (https://community.se.com/).
If you encounter any issues, please contact SchneiderCommunity.Support@se.com.

Important Announcement: WELCOME to the new Schneider Electric Community! Community is now no longer part of Exchange, and is now rebranded under se.com. If you have any bookmarks and links saved, we request you to update them to ensure that you continue accessing our community from this new location. For any issues that you might encounter as part of this change, please reach out to SchneiderCommunity.Support@se.com, and the team will help to get your issues resolved.

Invite a Co-worker

Send a co-worker an invite to the Exchange portal.Just enter their email address and we’ll connect them to register. After joining, they will belong to the same company.

Send Invite Cancel

How can we help?

How to handle frequent temporary voltage drops on input side of SMT1500C?

APC UPS Data Center Backup Solutions Forum

Schneider Electric support forum for Data Center UPS, software and services including our APC offers designed to share knowledge, installation, configuration, and general product use.

Back to APC UPS Data Center Backup Solutions Forum

This question was originally posted by Bernhard on APC forums on 8/3/2020

Not sure where to post this, since it is only tangentially related to my UPS, so hopefully this is a good (enough) spot.

I am using an APC SMT1500C UPS (with an AP9631 NMC2) to protect my networking gear, my NAS and my desktop from power outages (utility power is 120V nominal). My house-mate uses an old window air conditioning unit in his room, which is unfortunately on the same circuit as my home office. Every time the a/c unit's compressor kicks in, my UPS registers a voltage drop below 106V and about a second later a return of the voltage to normal. I suppose the inrush current for the a/c unit's compressor is the root cause of the temporary voltage drop.

This is in the U.S., California in a residential home with 120V/60Hz nominal voltage/frequency.

Yesterday (a weekend with hot weather) I got these messages about 14 times, though usually it's quite a bit less. I understand that I could lower the "low voltage boundary" on my UPS, but I actually want to protect my gear from a temporary voltage drop. Without my UPS, my NAS and my desktop wouldn't survive the voltage drop without a reboot.

* It is correct to assume that every time I get this message, my UPS will switch to battery power and then back a second later? If so, am I correct in assuming that this will wear out the relays on my unit prematurely?

* Since I'm looking for a "pluggable" solution that doesn't involve opening the a/c unit and installing a capacitor to buffer the inrush current, I've read that there is a type of product, called a "soft starter" that might help solve this problem by limiting the inrush current to the a/c unit's compressor.

Does anybody know of such product for the U.S. (120V, NEMA 5-15 plugs and receptacles, suitable for air conditioners) at a reasonable price (say less than $100-$150)?

Or perhaps there is an altogether different solution for this? Or is this perhaps a non-issue, because the SMT1500C's relays can easily handle 10000-20000 toggles over their life-time, even under load.

I would appreciate any advice on how to best approach this problem. Thanks in advance for your help.