Watt-hour Meter Research Articles

Calorimetry of High Polymers. III. A New Type of Adiabatic Jacket and Calorimeter

This paper describes a new type of adiabatic jacket and a modified calorimeter designed especially for the measurement of the specific heats of high polymers in the range −20 to +300°C. New features of the adiabatic jacket include the use of two dissimilar metals to increase temperature uniformity and a new method of closing and controlling the temperature of the ends. Calibration data using Al2O3 had an average precision of ±0.07 percent, although the uncertainty in an individual measurement, while ±0.1 percent up to 160°C. may reach ±0.5 percent at 300°C. Further studies of the use of an alternating current watthour meter in calorimetry are reported.

An autocorrelogram computer

A comparatively simple and inexpensive instrument capable of computing autocorrelation functions is described. It was built for the analysis of irregularity in yarn, roving and slivers in the textile industry, but it should find application in a much wider field in cases where the high accuracy of the expensive precision computer is not required. The instrument also lends itself to the computation of cross-correlation functions. Principles of operation and construction are given together with data on performance. The yarn irregularity is recorded on a magnetic tape as a frequency-modulated signal and use is made of a modified d.c. watthour meter for carrying out the multiplying and integrating operations.

Precise comparison method of testing alternating-current watthour meters

Precise comparison method of testing alternating-current watthour meters

A Direct Current Microampere Integrator

A current integrator with a current range of 0–10/1000 microamperes consisting of a feedback stabilized current amplifier whose output is fed to the current coil of a modified Thompson watthour meter is described. Inasmuch as the no-load speed of this meter is directly proportional to the current supplied, the desired integrated result is obtained by the use of a revolution counter operating at nearly zero torque. The net accuracy achieved is about one percent of full scale.

Apparatus for testing A-C watt-hour meters

WITHIN THE PAST DECADE much attention has been directed to increasing both the accuracy and speed of testing and calibrating single-phase a-c watt-hour meters. The availability of high accuracy transfer instruments has made possible the measurement of alternating current to an accuracy of 0.02 per cent.

A polyphase thermal kilovolt-ampere demand meter

The increasing need for a low-maintenance and relatively low-cost kilovolt-ampere demand meter has led to the design of a new type of thermal meter to accomplish this purpose. The complete unit includes a 2-element watt-hour meter as well as a thermal kilovolt-ampere demand meter in the same size base as a standard 3-element watt-hour meter, see Figure 1. Circuits for which the meter is available include: 3-phase, 3-wire; 3-wire network; 3-phase, 4-wire Y; and 3-phase, 4-wire delta.

Methods and apparatus employed in the testing of single-phase A-C watthour meters

DURING the past decade much attention has been directed to improving the accuracy and speed of meter testing on the part of manufacturers and users of a-c watthour meters. Numerous arrangements are in general use which might well be publicized for the benefit of those who feel the need for improved methods and equipment.

Calorimetry of High Polymers. II. Use of a Watt-Hour Meter

A method of using an alternating current watt-hour meter for the measurement of electrical energy in calorimetry is described. Reproducibility to better than 0.1 percent is readily obtainable, but the absolute accuracy depends upon the meter calibration.

Improvements in Transformer-Loss Compensators for Walt-hour and Var-hour Meters

Transformer-loss compensators provide an economical means for metering the loads of utility company customers supplied at transmission voltages on the low-voltage side of the power transformer bank by compensating the watt-hour meter to include the transformer losses in its registration. Improvements have been made in the basic compensator <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> by neutralizing the effect of the flow of meter potential circuit current through the copper-loss compensator. This improves the performance of the compensator, particularly on inductive loads, and makes possible its correct adjustment also for the higher values of losses incurred with var compensation. The burdens imposed by the compensator are sufficiently small to be acceptable in watt-hour metering practice, and for connection to the output side of standard var autotransformers. Under present-day conditions the use of transformer-loss compensators results not only in economies, but also in the conservation of critical materials that would be required for high-voltage instrument transformers on metering installations.

A Polyphase Thermal Kilovolt-Ampere Demand Meter

In the past decade, the use of thermal meters has increased rapidly for the measurement of demand. The measurement of kilovolt-ampere demand by thermal means has been an objective of the metering industry for years. A few years ago, a polyphase thermal-ampere demand meter was developed. Using such a meter as a basis, voltage compensation has been added. The result is a combination polyphase watthour and thermal kilovolt-ampere demand meter as described in this paper.

Discussion on “Parasitic forces existing in induction watt-hour meters” before the North-Eastern Radio and Measurements Group, at Newcastle-on-Tyne, 5th December, 1949

Discussion on “Parasitic forces existing in induction watt-hour meters” before the North-Eastern Radio and Measurements Group, at Newcastle-on-Tyne, 5th December, 1949

Discussion on “Parasitic forces existing in induction watt-hour meters” before the Southern Centre, at Southampton, 2nd November, 1949

Discussion on “Parasitic forces existing in induction watt-hour meters” before the Southern Centre, at Southampton, 2nd November, 1949

The author's reply to the discussions on “Parasitic forces existing in induction watt-hour meters”

The author's reply to the discussions on “Parasitic forces existing in induction watt-hour meters”

A new device for calibrating watt-hour meters

A NEW device has been developed to provide a better means of calibrating watt-hour meters, particularly in the field. With this device, the field testing of watt-hour meters is made much faster and easier as compared to the conventional methods of counting and timing of disk revolutions because an instantaneous and continuous visual indication of meter accuracy is obtained. In general, closer adjustment to correct registration is obtained than by the methods involving successive trials. The device is portable. No special disks, disk markings, or the like are required.

Recent developments in comparative methods of testing a.c. electricity meters

The paper deals mainly with developments in meter-testing methods which use a watt-hour meter as the standard of reference. A brief survey is included of methods, developed during the last forty years, in which some form of stroboscope has been included, and it is shown that such methods cannot be used for light-load testing owing to the fact that most meters are subject to cyclic variations. Particulars are given of recently devised schemes which incorporate a stroboscope for the higher loads and some other form of testing for the light loads. A description is then given of a new type of meter-testing unit which uses revolving optical compensators to view the disc of a meter under test, in order to compare its speed with that of a substandard meter. An image of the disc marks is obtained which is very similar to a stroboscopic image, but with theimportant difference that cyclic variations do not prevent its use for light-load testing. The new unit can therefore be used for testing meters at all loads from 1/20th to full load, and, as facilities are provided for testing meters having different constants, it is particularly suitable for use in supply authorities' test rooms dealing with different makes of meters, so that its application in this respect is considered in some detail.

A New Device for Calibrating Watt-Hour Meters

A NEW device has been developed to provide a better means of calibrating watt-hour meters, particularly in the field. With this device, the field testing of watt-hour meters is made much faster and easier as compared to the conventional methods of counting and timing of disk revolutions because an instantaneous and continuous visual indication of meter accuracy is obtained. In general, closer adjustment to correct registration is obtained than by the methods involving successive trials. The device is portable. No special disks, disk markings, or the like are required.

Parasitic forces existing in induction watt-hour meters

Parasitic forces existing in induction watt-hour meters

Discussion on “Parasitic forces existing in induction watt-hour meters” before the Measurements Section, 5th April, 1949

Discussion on “Parasitic forces existing in induction watt-hour meters” before the Measurements Section, 5th April, 1949

Parasitic forces existing in induction watt-hour meters

The paper describes research on the excessive wear on bearings of meters caused by parasitic forces existing in the meter. A simple experimental technique has been developed which should be of use to designers, and should lead, when new designs are contemplated, to the production of meters that are free from vibrational wear, and that will, in consequence, have an extended service period. Considerable improvement may be effected in many meters without serious modifications in design.

The author's reply to the discussion on “Parasitic forces existing in induction watt-hour meters”

The author's reply to the discussion on “Parasitic forces existing in induction watt-hour meters”