Abstract: Solid polymer membrane fuel cell product water which forms on the oxidant side of the membrane is removed from the active area of the cells in a fuel cell power plant by being absorbed into and wicked away from the active area by a porous carbon body which contacts the membrane. The carbon body may be an oxidant reactant flow field plate. The pores in the carbon body are partially filled with metal oxide granules which impart increased wettability and water absorption capacity to the carbon body.

Abstract: Ammonia which is found in fuel cell fuel gases is removed therefrom by passing the fuel gas stream through a scrubber bed of porous carbon pellets containing phosphoric acid. The ammonia reacts with the phosphoric acid in the scrubber bed to form ammonium phosphate compounds which remain in the scrubber bed. The ammonia content of the fuel gas stream is thus lowered to a concentration of about one ppm or less. By maintaining the temperature of the fuel gas stream passing through the scrubber bed in a range of about 400.degree. F. to about 450.degree. F. sufficient phosphoric acid will also be evaporated from the scrubber bed to replace acid electrolyte lost during operation of the power plant. Adjustments in the temperature of the fuel gas flowing through the scrubber may be made in order to match electrolyte losses which occur during different operating phases of the power plant.

Abstract: A steam reformer for converting a reactor fuel into a product gas includes a segmented catalyst bed. The steam reformer side walls have a thermal coefficient of expansion which is greater than the thermal coefficient of expansion of the catalyst. By forming low volume catalyst bed segments in the hotter portions of the catalyst bed, slumping and subsequent damage of the catalyst pellets is minimized. The catalyst bed is divided into segments whose volumes are inversely proportional to the temperatures of the various zones in the reformer. The segments are formed by utilizing sequential catalyst support assemblies which include perforated catalyst support members that are differentially spaced apart from each other by support assembly legs having varying lengths. Catalyst support assemblies with shorter length legs are used in the hotter zones of the reformer, and support assemblies with progressively longer length legs are used in the cooler zones of the reformer.

Abstract: A method for defining a pulse width modulation (PWM) waveform pattern to control the switching bridges in a power inverter system to produce a low harmonic content output voltage signal includes assigning a waiting factor to each harmonic produced by the switching bridges in the power inverter system. Harmonics reduced by the power inverter system are identified and other harmonics are selected to be reduced. The selected harmonics are represented one-for-one by a corresponding set of equations and the equations are solved by each of the switch points in the PWM waveform pattern. A program for finding the switch points is also presented.

Abstract: A novel electrical inverter includes a source of direct current (DC) signals, a plurality, N, of addressable electrical switching devices where N does not equal two configured in parallel to receive signals from the DC source. The electrical switching devices generate a plurality of output signals phased relative to one another. An output transformer has a plurality of parallel configured input inverter winding sets for receiving and transforming a respective one of the phased electrical switching device output signals, and a plurality of serially configured output winding sets providing three phased fundamental signals as the sum of the transformed signals.

Abstract: A porous plate for an electrochemical cell, such as plates 22, 24 having a sealing material disposed in an edge region 41 of the plate is disclosed. Various construction details including a method for making the plate are disclosed which increase the cross pressure material the plate can withstand. In one embodiment, the seal region 41 is impregnated with powder having a low structure and predetermined particle size using a pressurized liquid carrier.