tish53
Member
- Location
- richmond, VA
First I have to commend everyone on this site. By monitoring the threads over the last month, I have learned and relearned so much.
My question is about a 1500 kva, pad mount oil filled transformer 12,500 wye primary-- 480/277 wye secondary. Normally at most of our plants this incoming service transfromer is owned by the utility. In this case, we own the transformer and I am concerned about the load that has been added over the years.
I calculate 1804 full load amps capacity for the 1500 kva transformer at 480 vac. All our loads are 3 phase 480 vac. Mostly motor loads. We installed a data logger and the average load is around 2200 amps ( balanced across the 3 phases) for 7 hours per day 5 days a week. The load for the other 17 hours is around 500 amps.
Is there a thermal overload capacity, that this pad mount oil filled transformer can handle since it cools for 17 hours and then stresses for 7 hours. If so how do I calculate it and determine if 2200 amps is oK or is only 1900 amps ok.
I really apprciate any guidance anyone might be able to give.
Thanks again
My question is about a 1500 kva, pad mount oil filled transformer 12,500 wye primary-- 480/277 wye secondary. Normally at most of our plants this incoming service transfromer is owned by the utility. In this case, we own the transformer and I am concerned about the load that has been added over the years.
I calculate 1804 full load amps capacity for the 1500 kva transformer at 480 vac. All our loads are 3 phase 480 vac. Mostly motor loads. We installed a data logger and the average load is around 2200 amps ( balanced across the 3 phases) for 7 hours per day 5 days a week. The load for the other 17 hours is around 500 amps.
Is there a thermal overload capacity, that this pad mount oil filled transformer can handle since it cools for 17 hours and then stresses for 7 hours. If so how do I calculate it and determine if 2200 amps is oK or is only 1900 amps ok.
I really apprciate any guidance anyone might be able to give.
Thanks again