Abstract: A method of improving the control of a rotary cutting machine is disclosed. The cutting element of the rotary cutting machine being a filament which is rotated at high velocity under the control of a motor, such as powered by a battery or gasoline. The invention provides within the lower rotating head of the rotary cutting machine an optical source which illuminates the filament such that the distal rotating end of the filament provides a visual indication to an operator of the location of the rotating cutting element. In an embodiment of the invention the electrical power for the optical source is provided by providing an electrical generator within the rotary cutting machine such that for example the rotor is within the rotating head and the stator within the upper body of the rotary cutting machine.

Abstract: Apparatus for supporting an audio/video system, the system including a thin screen video display unit, video components operatively coupled to the display unit for generating video signals displayable by the unit, and audio components for generating audio signals, includes an elevator mechanism for the display unit and an exterior housing. The exterior housing includes a top opening sized to permit upward and downward movement of the display unit through the opening. The video and audio components are fixedly mounted to, the housing. The elevator mechanism extends upwardly within the housing and comprises an elevator platform adapted to carry the display unit between a lower position where the display unit when carried by the platform is retracted into the mechanism and an upper position where the display unit when carried by the platform is deployed above both the elevator mechanism and the exterior housing.

Abstract: A method and system are provided for measuring impedance and voltage characteristics of individual cells of multi-cell electrochemical devices, for example a battery or a fuel cell stack. The electrochemical system comprises a plurality of cells; a measuring device including a plurality of inputs connected across the plurality of cells to generate voltage and current signals indicative of voltage and current characteristics of the plurality of cells; a current supply/draw means for superimposing modulated current values through the plurality of cells; and a controller for controlling at least one system operating condition based on the voltage and current characteristics received from the measuring device, the controller being connected to the measuring device.

Abstract: A system and method for monitoring cell voltages for a plurality of electrochemical cells connected in series forming a cell stack. The method includes dividing the cells into at least two cell groups, measuring the voltage across each cell group and estimating the minimum cell voltage for each group based on the average cell stack voltage and an estimated number of deficient cells in each group. The lowest minimum cell voltage for the entire cell stack is then determined.

Abstract: A fuel cell power system has a plurality of fuel cell power modules, each module including a fuel cell and associated peripheral devices. Each fuel cell power module is controlled by its own local controller. A master controller controls each of the local controllers in accordance with overall system requirements. Optionally, a bypass allows the master controller to shut down and bypass a particular fuel cell power module, providing this system with greater flexibility, robustness and reliability. The modular system architecture also simplifies manufacturing, maintenance and repair.

Abstract: The electrical energy produced by a fuel cell under test is typically dumped in the form of heat energy radiated from a controllable variable load included in a conventional fuel cell testing system. This practice is wasteful since the electrical energy produced is not immediately employed to do useful work, stored for later use or sold to a power company after appropriate conversion. According to aspects of some embodiments of the present invention there is provided a fuel cell testing system having an energy conversion system that converts electrical energy produced by a fuel cell under test into another reliable form of energy that can be employed for some useful end, as opposed to simply dumping it as radiated heat energy.

Abstract: A method and apparatus are provided for measuring impedance and voltage characteristics of cells of multi-cell electrochemical devices, for example a battery or a fuel cell stack. Voltages are measured across individual cells, or groups of cells. At the same time, a load is connected in series with the electrochemical device. Both the device for measuring the voltages and the load are controlled together, preferably by means of a controller, which can include some form of microprocessor. This enables the load to be controlled to provide a desired combination of DC and AC current characteristics. By setting appropriate DC and AC current characteristics, desired characteristics of the impedance of individual cells can be measured.

Abstract: A system and method for monitoring cell voltages for a plurality of electrochemical cells connected in series forming a cell stack. The method includes dividing the cells into at least two cell groups, measuring the voltage across each cell group and estimating the minimum cell voltage for each group based on the average cell stack voltage and an estimated number of deficient cells in each group. The lowest minimum cell voltage for the entire cell stack is then determined.

Abstract: This invention discloses a self-contained, portable, cost-effective apparatus for measuring the real and imaginary components of a fuel cell's complex impedance at discrete frequencies. The apparatus comprises a CPU, a signal generation device, a fuel cell, a load bank, current and voltage sensing circuitry and a waveform acquisition device. The measurements can be done in real time and automated. The fuel cell's internal resistance can be calculated thereby providing an indication of the electrical efficiency of the fuel cell.

Abstract: A method and apparatus are provided for measuring impedance and voltage characteristics of cells of multi-cell electrochemical devices, for example a battery or a fuel cell stack. Voltages are measured across individual cells, or groups of cells. At the same time, a load is connected in series with the electrochemical device. Both the device for measuring the voltages and the load are controlled together, preferably by means of a controller, which can include some form of microprocessor. This enables the load to be controlled to provide a desired combination of DC and AC current characteristics. By setting appropriate DC and AC current characteristics, desired characteristics of the impedance of individual cells can be measured.

Abstract: A holding device for retaining insecticide material for insects such as ants, or for holding repellent material for insects or dogs. The device includes an elongated stake, preferably pointed on one end, and having a generally rectangular recessed area at the other end. A holding cup for the insecticide or repellent material is received in the recessed area of the upper end of the stake. The cup provides an opening in its rear surface for access by the insects to the material contained therein.