Abstract: A method and a device for use with horizontal boring equipment or excavating equipment while making an underground tunnel or digging near known or unknown electric power lines. The device indicates contact with the electrical conductors, whether the contact is momentary or continuous, by monitoring voltage gradients in the earth and activating an alarm if voltage is sensed.

Abstract: A valve and coacting control circuitry for filling variously sized and shaped receptacles to an exact settable level with a relatively high impedance fluid such as maple syrup. Errors caused by bubbles are avoided by controlling the flow rate through a shaped orifice for essentially laminar flow. Dripping is eliminated by shaping the exit orifice to prevent gravitational emptying of the faucet cavity when the valve is closed. Sensing of the fluid is accomplished with a flexible wire probe, not sensitive to the receptacle shape but may be adjusted to a desired height, connected to a sensitive electronic circuit with a very high input impedance which allows sensing a voltage through the high impedance fluid. Once started, the filling process need not be monitored by an operator who is then free to do other tasks.

Abstract: A variable reluctance electrical generator is disclosed having a unique structure which, for any given design parameters, tends to maximize air gap areas and thus minimize mmf drops thereacross. The mean magnetic flux paths all generally include a constant reluctance parasitic air gap and a variable reluctance active air gap. The portion of the magnetic circuit defining the active air gap is adapted to magnetically saturate before the portion of the magnetic circuit defining the parasitic air gap areas thus eliminating the parasitic air gap as a design limitation. In the exemplary embodiment the parasitic air gap is located radially outwardly of the active air gap areas such that the parasitic gap reluctance is much less than the minimum active gap reluctance. The design of the alternator is also such as to simplify its assembly during fabrication and to thereafter permit ready disassembly of its major components from one another for repair or other purposes.

Abstract: A multiple voltage electrical supply system continuously connected for individually charging a plurality of battery supplies continuously connected in series with one another to supply a plurality of load circuits having differing d.c. input voltage requirements and, typically, also having differing expected electrical power consumption rates. The system includes an alternator having electrically isolated generating windings disposed so as to insure that the magnetic flux linking each of the generating windings bears a substantially constant ratio to that linking the other of the generating windings. The exemplary embodiment has generating windings of different characteristic resistance per unit length such that there is an increased internal voltage drop in the winding intended to supply the lighter electrical load. The resultant voltage regulation characteristics are such that a single voltage regulator is sufficient to maintain both of the output voltages at a substantially constant predetermined ratio.