The traditional single-phase power cord is composed of a hot wire, a neutral wire and a ground wire. When multiple physically separated devices share a common power line, a ground loop may be formed due to the different ground potentials of the devices. These ground loops are particularly problematic in medical equipment and can cause trouble during equipment testing. For designers, it is difficult to measure ground loops with equipment that uses rectified line voltage. Ground test equipment such as oscilloscopes may inadvertently short-circuit the power supply in these equipment. Moreover, high-frequency noise will flow onto the AC power line, causing problems with sensitive sensors and instruments.
The dry type transformer provides isolation from the ground of the power cord, thereby eliminating ground loops and accidental grounding of test equipment. They also suppress high frequency noise on the power supply.
The dry type transformer provides galvanic isolation between the AC power line (main power supply) and the powered device. This means that there is no DC path between the two windings. They are mainly used for three purposes:
The first is to isolate the secondary from the ground (earth).
The second is to provide line (main) voltage step-up or step-down
The third is to reduce the transmission of line noise from the primary side to the secondary side or vice versa.
First of all, dry type transformers are transformers, and they have common characteristics of transformers . The primary and secondary windings are wound on an ordinary ferromagnetic core.
