摘要:

The great amount of attention now being given to the question of poor power factor suggests that tariffs such as are commonly used to-day are unsuitable in present circumstances. The paper contends that a wattless component of current, despite its having no energy content, involves the supply undertaking in extra running costs, and that therefore a charge should be levied for supplying it. A three-part tariff is proposed, embracing a periodic charge per kVA of maximum demand, a charge per kWh of energy, and a charge per kVA-hour of lagging wattless component. The additional running costs caused by wattless component are briefly touched on, and it is suggested that in a station with an average power factor of 0.7 the charge per kVA-hour of wattless component should be about one-ninth of the charge per kWh of energy. The question of metering the three-part tariff is discussed, and a method is shown whereby, with balanced load, a three-phase wattmeter may be “biased” to record the total energy consumption, plus or minus any desired fraction of the kVA-hours of lagging or leading wattless component.

DOI:10.1049/jiee-1.1926.0053

出版商:IEE    

年代:1926

数据来源: IET

摘要:

The first part of the paper summarizes the principal types of apparatus employed for the improvement of power factor, and gives a description of the modern static condenser and also of types of power-factor-rectifying plant that have been developed during the past three years.The second part of the paper outlines various forms of power-factor tariff in force in Great Britain, and is divided into two main classes; first, those based on kVA demand, and second, those incorporating a power-factor bonus or penalty on the total supply bill.Systems of metering employed in conjunction with power-factor tariffs are briefly dealt with.

DOI:10.1049/jiee-1.1926.0054

出版商:IEE    

年代:1926

数据来源: IET

摘要:

Further applications of the magnetic drum principle using the magneto-cohesion effect described in a former paper are treated in detail. A description is given of a new form of siphon recorder, with a very small transit time, for high-speed reception on commercial circuits (beam stations). The shoe of the recorder is of special construction and the operating force for a current of 4 mA is about 4 lb., which is extremely large for a recording instrument. Owing to the rapidity of motion of the siphon lever it is possible to secure legible tape records when atmospheric disturbances are neither too severe nor too frequent. The procedure adopted in reading and transcribing messages at the central receiving station is given. Other applications of the magnetic drum principle to a delayed-action relay and to the checking of clocks by wireless signals are described. The thermionic valve circuits associated with the various devices are discussed and portrayed diagrammatically.

DOI:10.1049/jiee-1.1926.0059

出版商:IEE    

年代:1926

数据来源: IET

摘要:

This paper gives a general description of the Post Office high-power radio station erected at Hillmorton near Rugby. The introduction sets out the requirements which the design had to meet.The paper is divided broadly into three Sections:-Power. Plant, High-frequency Generating Valve Plant, and Masts and Aerials.The first Section deals with the selection and type of power plant employed for converting the e.h.t. alternating-current supply to suitable e.h.t. direct-current and l.t. direct-current and l.t. alternating-current supplies for use on the various parts of the installation, and the precautions necessary in dealing with a wireless load of the magnitude involved. The method of providing lighting for the masts for warning aircraft of obstruction is given.The high-frequency generating-valve plant Section deals with the design of valve generating plant suitable for full-power transmission or subdivision into two transmitters for use with larger and smaller portions of the whole aerial, and gives the methods adopted for maintaining constant frequency, successive amplification and freedom from harmonics. This Section includes :-The e.h.t. direct-current supply; the general scheme of circuits; the filament supply; the excitation unit; consideration in regard to the size of power unit; the power unit; the paralleling of valves in a power unit; the paralleling of power units; safety devices and control circuit; the control table; types of coupled circuits; the design of inductances for high power; relative positions of amplifiers and aerial circuit; method of keying and shape of signal.The masts and aerial Section includes :-A brief general description of the 820-ft. masts; the method of insulating the masts and the stays; the method of staying the masts; tensions on the stays, etc.; the method of applying test load to top of masts; the aerial system; aerial insulation; aerial spreaders; earth system; curves of aerial resistance; voltage on aerial, etc.The final Section gives the general results obtained to date, and a brief description of the experimental telephony installation.

DOI:10.1049/jiee-1.1926.0060

出版商:IEE    

年代:1926

数据来源: IET