An air balancing unit on a nodding donkey.
An artefact intended for central conditioning and pressure increase of ventilation air.
A physical object that is driven by a prime mover by which energy is either constantly or periodically added to an amount of gas in order to increase its pressure.
A heater in which electric energy is converted into heat for useful purposes.
A physical object that is a general term covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment with associated interconnections, accessories, enclosures and supporting structures.