Open Frame Power Supply

Thermal Management
An open frame power supply reflects adherence to specifications as-is, with no enclosure included to encourage heat build-up. Many unique factors stemming from the application will affect the thermal performance of the power supply, such as the space surrounding it, heat dissipation of adjacent components, mounting position and orientation, the load to be applied, and available system cooling.

The open frame power supply’s datasheet may list a power-rating that reflects expected results as it has been tested with forced-air cooling, convection-cooling, or both. However, once an open frame power supply is installed, you should test the whole end-product’s system under any possible conditions that might push the end-products internal temperature to the max. If a single critical component’s maximum temperatures are met or exceeded, then additional cooling or remounting in a different location might be sufficient to reduce the operating temperature. If the open frame power supply is in an enclosure with inadequate cooling, components that exceed their maximum temperature ratings will suffer damage. Damaged components might not affect performance immediately, but the damage will cause premature failure or a faster degradation in performance.

Safety
Spacing problems can cause last-minute failure once an application is built if the measurements of the open frame power supply aren’t considered at the design stage. Mounting an open frame power supply inside your equipment enclosure requires careful observation of clearance and creepage distances on all sides. Creepage refers to a path between a conductive part and the boundaries of the equipment enclosure as measured along the surface of any insulation that’s present. Insulation can create a conductive path that can cause a short circuit, and shorts can cause fires, so observing a distance that avoids creepage is a safe practice.

Electromagnetic Compatibility (EMC)
An open frame doesn’t have an enclosure that also acts to shield electromagnetic interference. EMC control technology is meant to suppress noises that electronics generate, as well as protect an electronic device from external noise. Input and output wiring for equipment or devices should be placed far apart, while also avoiding placement near the open frame power supply.