Abstract: A system of changing over an electric power source for an electric motor vehicle including a secondary battery and a generator. The system is provided with a changeover circuit for changing over a state of connection between the secondary battery and the generator; and a controller for determining a power supply mode on the basis of a vehicle speed and an electric current value for driving a motor, the controller being adapted to instruct a changeover to the power supply mode to the switching circuit, thereby allowing high-speed and long-distance running.

Abstract: In an abnormality monitoring apparatus of the present invention, a plurality of detectors (13, 14) are arranged at a plurality of positions in the axial direction of a pipeline (11) to detect respective sound waves (37) propagating from a position (B) of occurrence of abnormality. The aforementioned position is calculated from a sound wave detection time difference between the detectors (13, 14) and position between the detectors (13, 14). The apparatus further includes an abnormal waveform memory unit (28) for storing the waveforms of a plurality of kinds of typical abnormal sound waves generated from abnormality on the pipeline (11). A display device (19) displays, on the same image screen, the abnormal waveform stored in the abnormal waveform memory unit and that of the sound wave detected. It is, therefore, possible for a monitoring personnel to readily identify a kind of abnormality occurred.

Abstract: Herein disclosed is a power unit for an electric car, which comprises: a first power supply mounted on the electric car and adapted to be always used; and a second power supply mounted on the electric car, if necessary. The first power supply may include a battery for effecting a travel of low speed and short distance by itself. The second power supply may include a battery module for effecting a travel of high speed and short distance and a generator module for effecting a travel of high speed and long distance.

Abstract: A device for measuring a surface potential at a photosensitive body including: a potential sensor for measuring surface potentials at a plurality of positions on the photosensitive body; a plurality of sample hold circuits; and an adder for adding each measured surface potential held in each sample hold circuit, or an adder which adds up each measured surface potential and average the sum. The addition or averaging of the measured values serves to eliminate eccentricity-induced errors and noise in the surface potential measurements, thereby allowing a correct surface potential to be obtained.

Abstract: A double beam scan type optical apparatus for use in a laser printer or the like. Such apparatus comprises two light sources and a lens system which provide scanning means for scanning a surface with parallel output light beams of the two light sources and beam distance controlling means for controlling the distance between the light beams. The reliability of the invention is improved by monitoring the intensity of the beams. Beam intensity checking means provide signals to verify that the intensity of each beam is maintained equal thus assuring that no abnormal conditions exist with the light sources or the lens system of the apparatus.

Abstract: An improved printing magnet drive device for use in a printing apparatus, such as line printer, is disclosed. The improvement comprises a constant voltage control means in which an output terminal voltage of a transistor is compared with a reference voltage and the comparison result is fed back to the transistor so as to control the output terminal voltage of the transistor to a predetermined value, whereby the voltage applied to the printing magnets is substantially maintained unchanged.