GB1014143A - Improvements in electrical apparatus - Google Patents

Abstract

1,014,143. Protective arrangements. GENERAL ELECTRIC CO. May 15, 1964 [May 20, 1963], No. 20312/64. Heading H2H. [Also in Division H1] The leakage current of an apparatus such as a capacitor start motor is rendered ineffectual by introducing into the apparatus a component which produces a current equal and opposite to the leakage current whereby the leakage current is neutralized. A capacitor start motor comprises a running winding 8 having an intermediate point M earthed and a starting winding 8 connected in series with a starting capacitor 10. The windings 8, 9 have earth leakage currents represented by C1-C6 and the capacitor 10 those represented by 11a 12a in Fig. 3, these leakage currents being symbolized in Fig. 3a by C7. A capacitor 16 is connected between the earthed housing 14 and a point X on one of the supply lines 6, 5 and this capacitor 16 is such that it produces a current equal and opposite to the leakage current I, thus compensating the current I and rendering it ineffectual. A three-phase apparatus is also described and a construction of a capacitor combining capacitors 10, 16 is also shown.