Abstract: A system and method for producing quality control evaluation information for each instrument in a large group of instruments making up a peer group which periodically (such as daily) run a set of control samples from a common lot of control materials. The control data from all instruments is reported electronically to a central station which collects all of the data and stores it along with identification information. The central station selects a golden peer group of the instruments which meet certain minimum operating criteria, and determines control targets from the golden peer group using techniques which assure horizontal and vertical robustness, so as to eliminate the need for any manual editing of the control data. A concordance correlation coefficient is determined for each instrument against the control targets, with the CCC covering an interval (such as a month).

Abstract: A system and method for producing quality control evaluation information for each instrument in a large group of instruments making up a peer group which periodically (such as daily) run a set of control samples from a common lot of control materials. The control data from all instruments is reported electronically to a central station which collects all of the data and stores it along with identification information. The central station selects a golden peer group of the instruments which meet certain minimum operating criteria, and determines control targets from the golden peer group using techniques which assure horizontal and vertical robustness, so as to eliminate the need for any manual editing of the control data. A concordance correlation coefficient is determined for each instrument against the control targets, with the CCC covering an interval (such as a month).

Abstract: In a charger for the battery of an electric vehicle, a stable time of day clock is provided to initiate charging at a preselected time of day, and to control at least a portion of the charge cycle. The clock can be set in accordance with the schedule established for the vehicle so that charging will be accomplished automatically during the scheduled time of day when the vehicle is not in use. In the case of a fleet of such vehicles, at the termination of use, each driver simply parks the vehicle and connects an AC power line; charging for each vehicle will be initiated as determined by the clock associated therewith. An indicating system is provided to advise the driver that power has been properly connected and charging will commence at the appropriate time.

Abstract: A propulsion system for an electric vehicle in which a chopper is used to provide controlled DC power to a separately excited DC propulsion motor. In order to provide increased torque for comparatively short intervals to meet on-the-road requirements, the propulsion motor is provided with two sets of shunt field windings, and switch means are provided for connecting the windings in series or in parallel dependent upon the torque demands on the system. Normally the system is operated with the shunt field windings in series. To meet transient demands for increased torque, such as rapid acceleration from a stop light or improved gradability on hills, means are provided for detecting such increased torque demands and switching the field windings from series to parallel configuration thereby increasing the field flux and causing the motor to produce increased torque. The parallel connected field windings compensate for the demagnetizing effect of high armature currents without the need for a series field winding.

Abstract: A variable duty cycle power converter operable in a current controlled loop and having means for delivering increased load current at low duty cycles for efficient use of the switching elements in the converter. A current limit is established for maximum duty cycle which allows current flow through the power switching elements near but within the ratings of the devices. The maximum limit is programmed as a function of duty cycle to allow increased load current flow while maintaining the current through the power switching devices within ratings. As a result substantially increased current can be provided at low duty cycles without the need for using power switching devices of increased rating.