APC East-ups SRVPM10KRIL voltage sesitivity

[m3orab]

Hi,
I am trying to lower the voltage sensitivity of APC easy-ups SRVPM10KRIL,

but i can't change it manually from the main screen or even from the power chute software.

[Teken]

Surprisingly, the full user manual does not indicate the sensitivity or transfer (upper / lower) voltage can be adjusted in the same way as the Smart-UPS line. 🙁

The only thing it mentions is the ability to adjust the output voltage / inverter voltage as seen here:

https://download.schneider-electric.com/files?p_enDocType=User+guide&p_File_Name=SUO_UM_990-91248B_E...

In other models a user can adjust the input line sensitivity from normal (low) -med - high. They can also adjust the upper and lower transfer voltage based on a defined range. Both features impact at what point the units AVR (Automatic Voltage Regulation) kicks in along with the unit going into battery only power.

I gather because this unit is a double conversion pure sine wave UPS. There isn’t a real need to have those features?!? As the power is constantly filtered and inverted to offer the cleanest AC power. Than again the SRT line is also a double conversion UPS and offers these same features. This is probably a marketing and  pricing tier APC is catering to. 

NOTE: You can adjust the bypass threshold on this unit which can in a round about way mimics a standard line interactive UPS.

[m3orab]

Thank you for your quick reply. I tried your advice to lower the bypass limit; unfortunately, I can't change the value as shown in the attached screenshot.

NOTE: When the main power source goes out, the UPS does not recognize the generator output voltage, so it keeps working on the battery. That's why I want to lower the sensitivity voltage.

[Teken]

Yes, understood as it relates to problems seen when on generator power. As I noted in another (APC) thread this is why it’s imperative that the selected UPS and generator are correctly matched.

As you know first hand one would think if the power went out and a generator was on site and providing backup power. This would allow the UPS to come back online and continue to recharge the batteries until called for again during a black out.

As you see that isn’t the case . . . 🤦‍♂️

The following comments are possible solutions (assuming) you have the decision / purchasing authority. ☝️

ATS: You can purchase and (Test) an Automatic Transfer Switch. Doing so would allow you to confirm if this hardware is well matched and operates in your specific environment. When power goes out the ATS will transfer to the primary or secondary power source you have selected. Keeping in mind the only purpose here is to allow you or others to either automatically or manually transfer power to another source.

It in no way resolves the issue of the UPS still running on battery only while dirty power is being seen by the UPS. ☝️

Because the ATS is now available you can have it transfer (automatically / manually) to the secondary generator power source. 👍 This would ensure the critical loads are powered at all times. 

Maintenance Bypass: A maintenance bypass is a manual switch. It mimics a ATS in a basic way as it allows a person to select where input power should come from. The reason I call out this very simple but important device is that it has no brains or complex electronics. So can operate in wide electrical conditions without much fuss. It doesn’t care if the generator power is considered (dirty) because you have the ability to (manually) choose to receive input power from this source! 👍

UPS: The obvious next solution is to test out new hardware that operates with your generator. Keeping in mind there are limits in doing so. We use the APC SRT double conversion models in our environment because it offers all the benefits of AVR, Upper / Lower Transfer, and Line Input Sensitivity, and Extended Battery Packs.

THD: Total Harmonic Distortion, is one of the biggest factors as it relates to what people often term (Dirty Power). 🤢 It’s very rare to see a building generator not able to produce proper voltage / frequency correctly. 

Having said this and referenced in the other APC thread. I noted even the best generator can produce dirty power!

Why?!?

Improper long term maintenance, calibration, and validation! That customer had the exact SRT UPS I have but his units refused to transfer back to generator power?!?

It was found the generator was out of specification and indeed was outputting dirty power! 🙁👎

So it goes without saying before anyone spends any finances on a ATS, Bypass, UPS, engage the building maintenance staff to validate what’s coming out of the wall. Again, it can’t be stressed enough just measuring the voltage / frequency isn’t enough. You and everyone else must be able to see and measure the actual wave and THD. If the scope shows a square / clipped, vs a pure sine wave there’s a problem! If THD exceeds 5% there’s a problem - at the generator!

The most common issues we see as it relates to a generator is timing, high / low rev, fuel related issues such as regulators, filters, pumps, air filter etc.

Every generator has a hour meter. This meter indicates how long the generator has been in service and running. Like any motor vehicle this dictates what maintenance must be performed when a threshold has been met. It can be as simple as an oil / filter change, plugs, air filter, timing adjustment, measuring compression. To a complete over haul to replace rings, adjust lash, replace / rebuilding the entire alternator / generator etc. 

Just some things to consider as you decide on your next steps. 👍🍺 Let us know how things turn out good or bad. Especially if you find out the generator just needed some TLC! 🤣 As it was the case for the other member here.