Supporting Motors on UPS
Supporting Motors on UPS
(OP)
Hi,
I have an application where we have of small number of "essential" motors (~10 motors, total load 15kVA) from a total load of 1200kVA.
As the load is so small I would prefer not to use a diesel back up generator. I was thinking of specifying a solid state UPS to support the load.
I was wondering does anyone have experience of this?
If so how did you deal with starting the motors? Size the UPS for the DOL starting current or install soft starters?
Any feedback would be most appreciated
I have an application where we have of small number of "essential" motors (~10 motors, total load 15kVA) from a total load of 1200kVA.
As the load is so small I would prefer not to use a diesel back up generator. I was thinking of specifying a solid state UPS to support the load.
I was wondering does anyone have experience of this?
If so how did you deal with starting the motors? Size the UPS for the DOL starting current or install soft starters?
Any feedback would be most appreciated





RE: Supporting Motors on UPS
Both of these solutions assume you have 3 phase motors. 1 phase motors present a whole new list of issues because of capacitors in some designs.
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Member, P3
rbulsara (Electrical)
I am not sure UPS is substitute for a generator. What is the purpose?
Read the Eng-Tips Site Policies at FAQ731-376
RE: Supporting Motors on UPS
How long do you expect them to run on the UPS? Generators can proivde extended run time, from hours to days as long as you can replenish fuel. While a UPS will have very limited run time. If you exceed say 30 mins, you are talking about quite a set of batteries.
Also UPS are one shot deal, once batteries are discharged it takes hours to recharge. Plus the maintenance of batteries is a recurring cost. In fact you will end up relacing batteries every 3-5 years.