The Predetermination of the By Auxi l iary Drives A ^ r * . / PN ι J - Β · W h i t e h e a d 5 e η η Γ · B y

A - C . Behavior of Dielectrics A . B a n O S / J r . 5 for bteam rower btations F. H H o i h s t e r 2 0

C H A R G E and discharge currents of any type of di­electric under continuous potential make it possible to predict accurately the loss, power factor, and capacity at 60 cycles. This is done by an empirical determination of the equation for the relaxation function of the dielectric at a given temperature, followed by the application of von Schweidler's method. .The method developed is available at any frequency, provided the continuous potential charge and discharge currents may be measured over initial time intervals comparable with the alter­nating period.

A convenient and sufficient expression for the relaxation func­tion is shown in this paper to be a sum of three exponentials. Further, experiment and analysis prove that the method of three exponentials predicts accurately the a-c. behavior of a dielectric at 60 cycles. The usual forms of irreversible conduction en­countered also are defined and classified. The case in which the initial constant current does not obey Ohm's law has been considered analytically as regards its contribution to the a-e. behavior. (A.I.E.E. Paper No. 32-45)

E S S E N T I A L L Y the full content of this paper is pub­lished in this issue of ELECTRICAL ENGINEERING, p. 20-1. Pam­phlet copies not available.

Steam Driven By

Auxiliaries for Power Plants w . Ρ D r y e r 2 1

E S S E N T I A L L Y the full content of this paper is pub­lished in this issue of ELECTRICAL ENGINEERING, p. 21-5. Pam­phlet copies not available.

Electrically Driven Auxiliaries By

for Steam Power Stations L W. S m i t h 2 0

Radio Interference from Insulator Corona

By F. O . M c M i l l a n 1 8

E S S E N T I A L L Y the full content of this paper is pub­lished in this issue of ELECTRICAL ENGINEERING, p. 25-8. Pam­phlet copies not available.

r U B L I S H E D in full in this issue of ELECTRICAL ENGINEERING, p. 3-9. Pamphlet copies not available.

Relationships A m o n g the Magnetic Properties of Magnet Steels and

Permanent Magnets By K. L S c o t t 1 9

^ Λ ? Ε Ν CIRCUIT remanence of magnet steels is the magnetic induction ab the magnetic equator of a permanent magne; with no external magnetizing or demagnetizing force. A new relationship has been found ecamecting the open circuit remanence of a permanent magnet witn the factors determining its value. By plotting the ratio of remanence to residual induc-ion as the ordinate, and using as the abscissa the ratio of the

product magnet lengths times square root of coercive force to the product of equivalent diameter times the square root of residual induction, a curve is obtained which appear; to be general and valid for all kpids of magnet steel.

Various quantities have been proposed for use as criteria of the magnetic quality^ of magnet steel, the quantity having the great­est theoretical justification being the maximum value of the product of the coordinates of the demagnetization curve for a given field, where the demagnetization curve is the portion of the hysteresis loop between residual induction and coercive force. Experimental justification of the validity of this criterion has been secured. However, it is approximated by the product of residual induction and coercive force, and as this latter quantity can be determined with less effort, it is preferable for routine use. (A.I.E.E. Paper No. 32-24)

18. O r e g o n S t a t e Co l l ege , Corva l l i s , Ore .

19 . W e s t e r n E l e c t r i c C o m p a n y , I n c . , C h i c a g o , 111.

Proposed Definition of Terms Used in Power System Studies

By H . K. S e l s 1 0

T H E INSTITUTE'S subject committee on definitions has submitted its report on terminology for power system inter­connection and stability studies. The report covers the five following general divisions: interconnection terms, stability terms, active power and reactive voltampere conventions, syn­chronous machine quantities, and response of excitation systems. In preparing its report the committee has reviewed technical literature and consulted representatives of members of various A.I E.E. committees.

The definitions presented are descriptive and cover the field practically in its entirety. While many of these may be con­sidered arbitrary, they have been chosen in the best interest of the profession. Their general adoption will lead to a better mutual understanding with less possibility of confusion and con­troversy on technical questions. (A.I.E.E, Paper No. 32M2)

Experience with Electrical Stability of Conowingo Station of Philadelphia By

c | - ρ R. A . H e n t z 1 3

electric Co. System j . w . J o n e s 1 8

BRIEF description of the Philadelphia Electric Company system with particular reference to the features influencing stability of the Conowingo hydroelectric station is

2 0 . S a r g e n t a n d L u n d y , I n c . , C h i c a g o , 111.

2 1 . S t o n e a n d W e b s t e r , I n c . . B o s t o n , M a s s .

4 4 ELECTRICAL ENGINEERING