Hello!

 

I have 3 phases coming into my business. However, some of the phases sometimes suffer from undervoltage which causes problems for my equipment.

Does anyone know of a device/transformer which converts 3 phases of different voltage into one reliable phase?

 

Thank you.

 

Moving to the Electrical forum. 

It's called a phase-selector relay https://www.novatek-electro.org/automatic-phase-selector-pef-320/

 

It picks the "best" phase and switches to feed the load from that one.

 

Use small ones like the one I linked to for individual loads or a bigger "whole installation" unit (with associated contactors) to feed everything.

 

They were pretty common when we lived in Delhi (along with small voltage regulators for each A/C unit). Our place had the poor-mans version, 3 outlets (one on each phase) next to the TV, plug the telly into the "best" phase.

Some UPSs are capable of doing this as well; the rectifiers are controlled a little differently than a normal UPS though— most will just switch to battery if one phase is out.