Hello,
Trying to double-check myself on some calculation here. I'm trying to size a transformer for an AC unit. The AC unit has three (3) indoor units and one (1) outdoor unit and are all fed by the same transformer that I'm trying to size here. The specs for the motors for the indoor and outdoor units are as below:
Indoor
208/230V 1PH, FLA 15amps
Outdoor
208/230V, 1PH, FLA 45amps
My question is:
(1)It doesn't specify the corresponding voltage level for the given FLA, so which voltage should I use for KVA calc.?
(2)Since it's single phase, I still need to convert the nominal voltage (in this case 208 or 230) to the line-gnd. voltage (120 or 133) for KVA calculation correct?
(3)Since all the loads in this case are single-phase loads, once I got the KVA, shall I divide the KVA by 3 to get the actual transformer size?
If I follow the steps above, and use 208V (thus 120V line-gnd voltage), and assume I size a 3-phase transformer, so the KVA rating would be: (15*3+45)*120/1000 * (1/3) = 3.6 KVA. So something like a 5KVA 3-phase transformer would be good for this application of feeding the AC?
Appreciate any feedback and comments. Thanks.
Trying to double-check myself on some calculation here. I'm trying to size a transformer for an AC unit. The AC unit has three (3) indoor units and one (1) outdoor unit and are all fed by the same transformer that I'm trying to size here. The specs for the motors for the indoor and outdoor units are as below:
Indoor
208/230V 1PH, FLA 15amps
Outdoor
208/230V, 1PH, FLA 45amps
My question is:
(1)It doesn't specify the corresponding voltage level for the given FLA, so which voltage should I use for KVA calc.?
(2)Since it's single phase, I still need to convert the nominal voltage (in this case 208 or 230) to the line-gnd. voltage (120 or 133) for KVA calculation correct?
(3)Since all the loads in this case are single-phase loads, once I got the KVA, shall I divide the KVA by 3 to get the actual transformer size?
If I follow the steps above, and use 208V (thus 120V line-gnd voltage), and assume I size a 3-phase transformer, so the KVA rating would be: (15*3+45)*120/1000 * (1/3) = 3.6 KVA. So something like a 5KVA 3-phase transformer would be good for this application of feeding the AC?
Appreciate any feedback and comments. Thanks.