An open frame power supply does not have a case that contains electronic components and PCB. Instead, the components attach to the PCB board and expose to the environment directly. Although there is no external protection to the power supply, such configuration comes with a key benefit. Engineers choose an open frame power supply over an enclosed unit when dimension and cost are the primary concerns. In addition, without an external frame that prevents heat dissipation as the circuit operates, the power supply is able to work with more stable performance. The undissipated heat is harmful to electronic components and will eventually jeopardize the lifespan of the power supply. That said, the open frame power supply is not necessarily the better choice compared with the enclosed type. Rather, you should take the working environment and application into account in order to make the right choice you need.