I am studying for an Broadcast Engineering test and I have a sample test. I believe my problem is in how they worded the question. Perhaps I have over analyzed it... the question is:
"A three-phase delta connected 100V line is attached to three groups of lamps, each requiring 12A at unity power factor, and an AM transmitter with a power supply draw of 20A in each phase at 80% power factor. Find the current for each load carried by each line wire."
Answer is 57.2A
I know that IL = IP in a Delta... I have been using Pl= Il X El X 1.73 / 100 = Amps per line. So they say one load is 20A per phase.... I think it is the "three groups of lamps, each requiring 12A at Unity Power Factor" that is the confusing part. is it 3 sets of lamps with 12A per lamp? 12A per group? is it 1 set of lamps per phase? 3 sets per phase? I and another engineer (who is much more seasoned than I) have run the number in all scenarios, and we cant get that same answer. It must be something simple that we are both missing. The 1.73 is the Square root of 3. Any help would be amazing lol. out of the 50 question test this is the only one that I have gotten wrong. Thank you all!!
"A three-phase delta connected 100V line is attached to three groups of lamps, each requiring 12A at unity power factor, and an AM transmitter with a power supply draw of 20A in each phase at 80% power factor. Find the current for each load carried by each line wire."
Answer is 57.2A
I know that IL = IP in a Delta... I have been using Pl= Il X El X 1.73 / 100 = Amps per line. So they say one load is 20A per phase.... I think it is the "three groups of lamps, each requiring 12A at Unity Power Factor" that is the confusing part. is it 3 sets of lamps with 12A per lamp? 12A per group? is it 1 set of lamps per phase? 3 sets per phase? I and another engineer (who is much more seasoned than I) have run the number in all scenarios, and we cant get that same answer. It must be something simple that we are both missing. The 1.73 is the Square root of 3. Any help would be amazing lol. out of the 50 question test this is the only one that I have gotten wrong. Thank you all!!