Use of a UPS to Supply Power to an Agilent GC or GC-MS System

You asked specifically about the rough pump and so I tried to answer your specific question.

Plugging the rough pump into the wall instead of into the GCMS is only recommended for troubleshooting purposes.  A properly sized UPS that can handle the required demands as described in the document will handle the GC and MS.   A UPS that meets the criteria outlined in the document will work and the operator would be fully responsible for the repair of any issues caused by the UPS, which is the same as any repairs caused by faulty power.

Isothermal or not, the oven heater is fired on zero crossing and the current demand changes all the time, so any UPS/conditioner must be able to handle the demand as described in the document.

The power outages happen very rarely these days in comparison to the past. When they did, they were usually unpredictable(hours to half a day or frequent). The primary reason we got a UPS system was to allow ample time to finish the sequence and shut down the system in the event that the outage would last for days or  that the lab would be inaccessible due to inclement weather. We experienced a 4 day outage back in 2021 and took quite a few days to get back up in running during a busy time of year.

So maybe I'm missing something but what about if the rough pump is connected to the mass spec and the mass spec is connected to the UPS? Could this cause a pump to malfunction?

On a separate note what if the method for the GC is isothermal?

The rough pump itself, unplugged from the mass spectrometer and plugged separately into a UPS, could be on a UPS as long as that UPS/conditioner provides true sine wave output and has sufficient current capacity for the pump.  How long are your power outages?  How bad is your power?   It takes a UPS with quite a bit of battery reserve to run even just a rough pump for hours and hours.   

GCs and GCMS systems engage the heaters on the AC zero crossover, when the sine wave goes over zero volts.  If the UPS/conditioner isn't true sine wave, the electronics do not know when to cycle the heaters and the instruments won't function correctly.  The total cyclic current draw with all the heaters heating up is also a problem for some UPS/conditioners.  

A UPS that meets the criteria outlined in the document will work and the operator would be fully responsible for the repair of any issues caused by the UPS, which is the same as any repairs caused by faulty power.

I stumbled upon this powerpoint and have a question...Rough Pumps on Agilent 5977 GCMS

Can someone explain why a rough pump specifically should not be run on a UPS? What category does a rough pump fall in? What could potentially happen to the pump if run on a UPS?