Abstract: A hybrid energy system heats or cools a plant with a geothermal unit powered at least partly by a fuel cell, which may also power other devices. The thermal fluid for the geothermal unit also cools the fuel cell via a heat exchanger. A digital controller bypasses a variable portion of the thermal fluid around the heat exchanger to regulate the fuel-cell temperature.

Abstract: A method for making an armature assembly is provided that reduces the level of acoustic noise during initial engagement of the armature, during slippage, and during disengagement. The armature assembly includes an armature disc, an annulus of sound damping material, and a hub assembly having a flexible spider with a web portion. The armature assembly is made by first forming the annulus of sound damping material with a plurality of angularly spaced molding tabs. The annulus is affixed to the web portion of the hub assembly using the molding tabs and is then compressed by securing the armature disc to the web portion such that one side of the annulus is disposed against the web portion and a second side of the annulus is disposed against the armature disc.

Abstract: An electromagnetic clutch in which an annulus of sound dampening material is sandwiched between an armature disc and a hub assembly, particularly a web portion thereof. The annulus and web coact to define a constrained-layer damping system for reducing noise when the armature disc is snapped into engagement with the rotor of the clutch, slipping prior to lockup, while the armature is magnetically locked to the rotor, and also during slipping and disengagement of the armature disc. The design provides a reduced axial-length package relative to prior armature assemblies incorporating constrained-layer techniques.