Abstract: An air brake monitoring system for monitoring a pressure of the system and providing various alarms and/or warnings to a user. The air brake monitoring system configurable to function with the existing wiring of the vehicle and including an air brake monitoring device to be positioned in the vicinity of a brake valve. The air brake monitoring system is further provided to monitor the electrical stoplight power transmitted to the ABS brakes as well as the vehicle static/dynamic condition.

Abstract: A control circuit for a sump pump or other pump that controls the liquid level in a vessel. The liquid is maintained between upper and lower levels defined by probes in the vessel. The probes are associated with comparators and connect with one comparator input. The upper limit comparator connects with the gate of an SCR which supplies current to the lower limit comparator and also to a relay which controls the on/off condition of the pump. The output of the lower limit comparator controls a switching transistor which is arranged in a series circuit with the SCR and relay coil. Once the SCR is conductive, it is latched in the conductive state until the transistor is made nonconductive by the lower limit comparator. In a sump pump application, latching of the SCR allows the pump to remain activated after the liquid level is reduced below the upper probe.

Abstract: A sump pump powered by a rechargeable battery has a circuit for monitoring the battery voltage and controlling charging of the battery. Four comparators monitor the battery and control two flip flops one of which operates the pump in cooperation with a float switch and the other of which turns the battery charging circuit on and off. The circuit is arranged so that when the battery is in its discharge cycle, the float switch controls the pump and the charging circuit comes on only when the battery voltage is in a low range. In the charging cycle, the pump is locked out in a low voltage range of the battery and is controlled by the float switch only in a high voltage range.

Abstract: A method and apparatus are disclosed for preventing burnout of a fluid pump. The pump includes a pump casing having a pumping member disposed for movement therein. An outer casing is disposed about the pump casing so as to form a reservoir therebetween. Additionally, the pump casing is provided with a plurality of openings in order that pumped fluid may be recirculated between the interior of the pump casing and the reservoir. The openings are so constructed and arranged as to directly lubricate the pumping member as well as to insure continuous recirculation of the pumped fluid in the event the supply of fluid to be pumped should decrease.