Abstract: An electrically powered service vehicle having a plurality of programmable electrical stations is exemplified by a food service vehicle for use with food serving trays including internal heating elements for providing localized areas of heat on the trays for maintaining food placed thereon at a desired temperature. The vehicle has a plurality of storage compartments, each of which holds a plurality of the food serving trays in vertically spaced relation to each other. An on-board d-c. power source is connected to the heating elements within the trays via a plurality of electrical contacts within each storage compartment. A d-c. drive motor for propelling the vehicle is selectively connected to the power source through a drive control. The electrical contacts within the storage compartment are positioned to engage corresponding contacts on the trays when the trays are inserted into the storage compartments.

Abstract: A battery charging system for charging a battery from a conventional a.c. power source has a leakage reactance transformer connected between the power source and the battery for reducing the voltage of the power source for application to the battery. The power source is connected directly across the primary winding of the transformer to charge the battery at a high rate until it is charged to about 90% of the final capacity. A voltage sensing circuit is activated when the battery reaches about 80% of the desired final voltage, and this circuit energizes a timing motor which maintains the connection of the source directly across the primary winding of the transformer for a period of one hour, which is the normal time required for the battery charge to be increased from the 80% level to the 90% level. At the end of the 1 hour period, a cam driven by the timing motor operates a switch to connect a resistor, which is external of the transformer, in series with the primary winding of the transformer.

Abstract: A storage system for a plurality of food trays includes one or more storage modules each having multiple pairs of horizontal rails for supporting a plurality of trays with the hot food positioned along one side wall of the module and the cool food along the other side wall. Forced air inlet means in the rear wall and adjacent the side wall on the hot food side of the tray produces a forced air stream flowing forwardly through the module over the hot food on the trays. A door covers the front of each module and forms air outlet means adjacent the module side wall on the hot food side of the trays so that the forwardly flowing air stream exits through the door. This system is particularly suitable for use with trays which have electrical heating elements embedded in one side of the tray for heating the hot foods thereon.

Abstract: A programmable electronic control system for an array of electrical stations exemplified by food tray stations each of which is adapted to receive a food tray having two or more electrical heaters embedded in the tray. Each tray is detachable from its station. A separate power circuit is associated with each heater element at each tray station for supplying separately controllable power to each individual heater. A manually controlled programming channel is connected to each power circuit and includes means for generating control signals to enable or disable each separate power circuit to permit the programming of the entire array of tray stations. A manually controlled station reset device is connected to the programming channels for each tray station to remove any enabling control signals generated by the respective programming channels for that station to permit the re-programming of individual tray stations.