Factors Affecting Size and Cost
| Supply Frequency: | The size and cost of a transformer
increases when the Rated Frequency is the lowest frequency which will allow Max. Supply Volts without saturating the core. |
| Primary Configuration: | The size and cost of a transformer
increases when you move down the listing of primary windings. A 5-LEAD primary requires more copper than 2+2 primary. A LADDER is the least economical primary. |
| US/Foreign Version: | A transformer for 60Hz with a single
primary will always cost less and be smaller than a multiprimary 50Hz transformer. The savings are often large enough to make it economical to use two different versions of a transformer, one for the domestic market, and another for foreign markets, in spite of the smaller lot sizes of each transformer. |
| Rectifier Circuit: | DHW circuits and CTB circuits with
unsymmetric load require a larger and costlier transformer than regular FWB circuits. Circuits with L-filter (FWBL and DHWL) require a smaller transformer than circuits with capacitor filter (FWB and DWH), but the inductor adds size and cost to the system. |
| UP/UPnom: | The size and cost of a transformer
increases rapidly when UP/ UPnom is decreased for constant output. |
| Duty Cycle: | The size and cost of a transformer goes
down with decreasing DUTY CYCLE,
but the LOAD REGULATION increases. |
| Load Regulation: | If you specify more than one set of data
for the same secondary, you do in reality specify LOAD REGULATION in addition to rated data. The AC LOAD REGULATION for a transformer varies with its Rated Power when it is designed for normal temperature rise, from about 20% for a very small transformer to about 2% for a large transformer. If you specify data corresponding to a smaller LOAD REGULATION than normal for the transformer's power rating, the size and cost of the transformer will increase. If you specify data corresponding to a larger LOAD REGULATION than normal for the transformer's power rating, your specification cannot be met without overheating of the transformer, unless you provide forced cooling and/or external resistors in series with the transformer. |