UPS for robot?

I'm not sure anyone makes UPSs for high-voltage 3-phase AC.

Power Conditioners are the closest standard product I can think of: https://www.mscdirect.com/browse/tn?sear…r%20conditioner

However, those only restrain voltage spikes -- if your mains power actually drops out entirely, even briefly, a power conditioner may not be enough.

if this is something that happens a lot, did you try to monitor power quality? i would attach logger to collect some data.

as for "bridging the gap" during brownouts, you could use alternate power source.

for example KUKA has mobile platforms (KMP/KMR/OmniMove)

obviously they are using batteries for primary power.

When they are fitted with robot arm, robot controller gets power from 3Phase Sine Inverter...

but power outage is not likely to cause much damage. this is working of transients (voltage spikes) that exceed the normal limits. normally this is something that line filter and power supply should be able to cope with - within reason... (nothing is going to help you if there is a lightning strike nearby).

so some sort of clamping is needed (TVS, MOV).

Industrial High Energy Varistors - Littelfuse

https://www.ebay.ca/itm/186169428756?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D259364%26meid%3Db2a39c4d616048a2aeaa99eaba461e4d%26pid%3D101195%26rk%3D2%26rkt%3D12%26sd%3D305212848315%26itm%3D186169428756%26pmt%3D1%26noa%3D0%26pg%3D4429486%26algv%3DSimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV1V2V4ItemNrtInQueryAndCassiniVisualRankerAndBertRecallWithVMEV3CPCEmbeddingSearchQAuto&_trksid=p4429486.c101195.m1851&amdata=cksum%3A186169428756b2a39c4d616048a2aeaa99eaba461e4d%7Cenc%3AAQAIAAABYMF6rapl24zPGkjYHfiSlLTuBicNRv1Nr6Iohq4bMvd7DlxPac1R4%252FnhV6ZdsOB3e44VPDg3LMjzKh6h9F%252BnyuldWK33VEcBpK6UyRXA9oDADzwEJIB%252BjrUQktYR0EluQdk0jMCISI62ak4peNZttnRbSFGqwdC47qFkTZC5xxTjp9bHcL3qg0RoXvktnjH9RXoRCdwuJA9qnCBlShy4BbHONqV9OdEAoOLKq3GXF8dc1ZEa5D%252BAW6Fyj2VCLeUp%252Fl6PYQEOTFaH1kkmZadgA0bUvpah%252BmKUtK5acFJXRWLvIHQR7T8Djpg9LeH9qJ8xPGt2Fi%252BwqQU0qS%252BR9OS7iRrAMINMmtFimYKLUWqCDNZubtOGccROoG6XXVH8DAVsS8YEuZB0shx2luVehkVoYMEXWbiA32FMHjNjnzN7a2DBSq4AWRHpUGwgtEtTQ%252FMX0h9dA5K7OAStfA9Lq9IU1Pc%253D%7Campid%3APL_CLK%7Cclp%3A4429486

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Most of the hits I found searching appear to be for data centers, rather than heavy industrial equipment, but it might be enough to prevent the robots from taking damage:

Three (3) Phase UPS Power Supply | Mitsubishi Electric

Choose a three phase power supply system from 10kVA to 2000kVA to distribute industrial power over long distances. Three (3) phase UPS balance loads for a…

www.mitsubishicritical.com

Still, you might want to have the robots perform a controlled stop when the grid power drops out -- a UPS that that handle the demands of robots in operation would probably be very expensive.