Single phase small transformer
An single phase small transformer is typically an isolation transformer. This is a transformer which is used to decouple two circuits of a specific voltage. This voltage can vary between input and output but typical single phase voltages wold be 220VAC, 230VAC and 240VAC Line to Neutral. The typical ratings for small isolation transformers is from 1VA to 10kVA single phase. An isolation transformer allows an AC signal or power to be taken from one device and fed into another without electrically connecting the two circuits. Isolation transformers block transmission of DC signals from one circuit to the other, but allow AC signals to pass. They also block interference caused by ground loops. Isolation transformers with electrostatic shields are used for power supplies for sensitive equipment such as computers or laboratory instruments. Transformers include a grounded shield between the primary and the secondary windings as an optional extra. This screen has a very high coupling to the input winding. Hence it reduces common mode noise on the input side. Differential noise can magnetically couple from the primary to the secondary of an isolation transformer. This requires other measures, such as a filter, to block differential noise from the secondary of an isolation transformer. Isolation transformers are also used for the power supply of devices not on ground potential as one option. Equipment susceptible to damage by poor line conditions will be protected, and noise and harmonics generated by components on the secondary side will not be allowed to transmit onto the main supply line.