Your browser does not support JavaScript!

An investigation of parasitic brush currents in single-phase commutator machines, with particular reference to the repulsion motor

An investigation of parasitic brush currents in single-phase commutator machines, with particular reference to the repulsion motor

For access to this article, please select a purchase option:

Buy article PDF
(plus tax if applicable)
Buy Knowledge Pack
10 articles for $120.00
(plus taxes if applicable)

IET members benefit from discounts to all IET publications and free access to E&T Magazine. If you are an IET member, log in to your account and the discounts will automatically be applied.

Learn more about IET membership 

Recommend Title Publication to library

You must fill out fields marked with: *

Librarian details
Your details
Why are you recommending this title?
Select reason:
Proceedings of the IEE - Part IV: Institution Monographs — Recommend this title to your library

Thank you

Your recommendation has been sent to your librarian.

The parasitic currents which flow in the armature coils at the moment of commutation have a pronounced influence on the performance of all single-phase commutator motors; the paper shows how their effects may be calculated. Although the methods described are applicable to all such motors, the repulsion motor is chosen for particular treatment because it is peculiarly suitable for illustrating the principles involved. The methods are also applicable to the analysis of parasitic effects in dynamo-electric amplifiers.If the repulsion motor is tested with constant stator current and varying speed, the performance can be represented by loci of rotor open-circuit voltage, rotor short-circuit current and stator voltage. If the parasitic currents are eliminated by using very narrow brushes, the vector loci are found to be three straight lines. Tests with the normal brushes give very different results, which illustrate the influence of the parasitic brush-currents. A comprehensive theory for the motor with normal brushes is developed, which enables the performance to be expressed in terms of ten characteristic constants, all measurable. The comprehensive theory shows good agreement with the test results.The parasitic currents override non-linearities in their influence on the general pattern of behaviour of the machine. The theory given is based on the assumption of linearity, yet it gives a good insight into the performance under non-linear conditions, some examples of which are given.


    1. 1)
      • T.F. Wall . The Single-Phase Repulsion Motor. Electrician
    2. 2)
      • E.G. Cullwick . The Theory of Some A.C. Commutator Motors with Series Characteristics. Canadian Journal of Research, Section A
    3. 3)
      • E. Arnold . Brush Contact Resistance. Electrician
    4. 4)
      • C.M. Cock . Discussion on Railway Electrification in Great Britain. Proceedings I.E.E., Part I
    5. 5)
      • Traction at the Industrial Frequency. Railway Gazette
    6. 6)
      • C.W. Olliver . (1927) , The A.C. Commutator Motor.
    7. 7)
      • H.R. West . Theory and Calculation of the Squirrel-Cage Repulsion Motor. Transactions of the American I.E.E.
    8. 8)
      • P.H. Trickey . Performance Calculations on Repulsion Motors. Transactions of the American I.E.E.
    9. 9)
      • B.A. Behrend . (1921) , The Induction Motor and Other Alternating Current Motors.
    10. 10)
      • Robson, C.: `Brush Phenomena in the Repulsion Machine', June 1950, Dissertation for Honours, , Bangor, H.5003.
    11. 11)
      • F.J. Teago . The Atkinson-Type Repulsion Machine as a Motor and Generator. Journal I.E.E.
    12. 12)
      • H.R. West . The Cross-Field Theory of Alternating-Current Machines. Transactions of the American I.E.E.
    13. 13)
      • Thomas, I.: `The Vector Loci of the Repulsion Motor', June 1949, Dissertation for Honours, , Bangor, H.4905.
    14. 14)
      • O.S. Bragstad , S.P. Smith . Calculation of the Characteristic Curves of Single-Phase Series Commutator Motors. Electrician
    15. 15)
      • A. Fraenckel , B.J.M. Lane . Short-Circuit Losss in Alternating Current Commutator Motors. Electrician
    16. 16)
      • C.P. Steinmetz . (1900) , Alternating Current Phenomena.
    17. 17)
      • Single-Phase Electric Traction at 50 cycles. Engineering
    18. 18)
      • Winterbottom, J.: `The Application of Thévenin's Theorem to the Repulsion Motor', June 1951, Dissertation for Honours, , Bangor, H.5105.
    19. 19)
      • The First 50-Cycle Locomotive for S.N.C.F.. Railway Gazette
    20. 20)
      • D. Morris . Some Tests on an Exact Practical Theory of the Transformer. Proceedings I.E.E., Part II

Related content

This is a required field
Please enter a valid email address