Machine-tool drive units
In the terminology used in the original article, a drive unit provides the main cutting drive for tools on a spindle head. It works with a powered slide and spindle head, while the powered slide provides the feed movement.
A spindle head mounted on the drive unit delivers the principal cutting motion. This arrangement is used in different types of modular machine tools with guided machining. The source also discusses the dimensions of the mating surfaces between the drive unit, spindle head and slide as part of the unit's rigidity.
Power supply boxes for switching equipment
A power supply box serves a different purpose: it supplies operating power for vacuum circuit breakers and other high-voltage switches.
The design described in the source takes a 220 V or 380 V AC input and uses thyristor-controlled voltage regulation and rectification. Depending on the configuration, it can provide adjustable DC output or AC output for individual opening and closing operations.
The article gives an example of a compact, lightweight and portable unit for on-site commissioning of high-voltage switches. These are descriptions of the equipment discussed in the source, rather than specifications that apply to every power supply box.