Edward M. Marwell

Bio: Edward M. Marwell is an academic researcher. The author has contributed to research in topics: Coulometer & Mercury coulometer. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

Coulometer with end of integration color change indicator

Abstract: A coulometer signaling device is disclosed which indicates when a particular machine has been used for a predetermined amount of time. The device comprises a mercury coulometer which includes an electrolyte whose color changes when the mercury deposited on the anode of the coulometer has been depleted. The end of the tube near the coulometer is somewhat enlarged and a lens is placed over this end in order to make the color change more visible.

Electrical propulsion systems for a golf car

Abstract: A method and apparatus for preventing overspeed of an electrically powered golf car having a shunt wound direct current electric motor with an armature winding and a field winding serially connected to respective switching devices and to a source of on-board direct current electric power. The golf car includes a control adapted and connected to regulate the current in each of the armature and field windings for controlling speed in response to an operator's command. The golf car incorporates overspeed detection by sensing the magnitude of current in each of the armature winding and the field winding and detecting when the current in the armature winding reverses direction. The magnitude of the armature winding current upon such reversal is compared to a preselected value and an overspeed signal generated when the reverse current magnitude exceeds the preselected value. The field current is then controlled, in response to the overspeed signal, to limit the speed of the golf car to inhibit the overspeed condition. Additionally, the voltage at the motor armature winding is monitored during a time period when the motor is in a non-energized condition and a motion signal indicative of motor armature rotation is provided upon detection of a motor armature winding voltage. The motor field winding is energized, in response to the motion signal, with a voltage of a polarity for generating a field current to cause the motor to act as an electric current generator and the current generated by the motor armature is circulated through a plugging diode and into the motor armature for electrically retarding rotation of the motor armature by plug braking.

Indicator device for indicating the time integral of a monitored parameter

Abstract: A device for indicating the time integral of a monitored parameter comprising a strip of electrochromic material (2), e.g. tungsten trioxide, an electrode (3) at one end of the strip and an electrolyte (4) arranged so that, upon activation, electrons pass from the electrode (3) to the electrochromic material (2) causing the latter to change color so that a color change boundary (7) advances along the strip, the rate of advancement being determined by the supply of electrons between the electrode (3) and the color change boundary (7), which in turn is responsive to changes in the monitored parameter. The device may be used in the form of a self-powered cell needing no power source, as a time temperature indicator suitable for application to perishable commodities.

Electrical propulsion systems for a vehicle

Abstract: A method and apparatus for preventing overspeed of an electrically powered .[.golf car.]. .Iadd.vehicle .Iaddend.having a shunt wound direct current electric motor with an armature winding and a field winding serially connected to respective switching devices and to a source of on-board direct current electric power. The .[.golf car.]. .Iadd.vehicle .Iaddend.includes a control adapted and connected to regulate the current in each of the armature and field windings for controlling speed in response to an operator's command. The .[.golf car.]. .Iadd.vehicle .Iaddend.incorporates overspeed detect sensing the magnitude of current in each of the armature winding and the field winding and detecting when the current in the armature winding reverses direction. The magnitude of the armature winding current upon such reversal is compared to a preselected value and an overspeed signal generated when the reverse current magnitude exceeds the preselected value. The field current is then controlled, in response to the overspeed signal, to limit the speed of the .[.golf car.]. .Iadd.vehicle .Iaddend.to inhibit the overspeed condition. Additionally, the voltage at the motor armature winding is monitored during a time period when the motor is in a non-energized condition and a motion signal indicative of motor armature rotation is provided upon detection of a motor armature winding voltage. The motor field winding is energized, in response to the motion signal, with a voltage of a polarity for generating a field current to cause the motor to act as an electric current generator and the current generated by the motor armature is circulated through a plugging diode and into the motor armature for electrically retarding rotation of the motor armature by plug braking.

Calibration method using a stable and safe redox standard solution

Abstract: The present invention is directed to a stable, non-hazardous solution for calibrating oxidation-reduction potential (ORP) measurement cells. The redox standard calibration solution of the present invention consists essentially of an aqueous solution containing the triiodide/iodide redox couple. In a preferred embodiment, the solution of the present invention consists essentially of an aqueous solution containing up to about 0.01 moles per liter of iodine (I 2 ) and at least about 1 mole per liter of potassium iodide. In a most preferred embodiment, the solution of the present invention consists of an aqueous solution of 4 molar potassium iodide (KI) and 0.0067 molar iodine (I 2 ).