GB716893A - Improvements in or relating to rotary inductor machines - Google Patents

Abstract

716,893. Inductor generators, selsyns. SANGAMO WESTON, Ltd. Jan. 18, 1952 [Jan. 18, 1951], No. 1531/52. Class 35 [Also in Groups XXXVI and XXXVIII] An inductor type machine which may be used as an alternator or a transmitting or receiving selsyn has a rotor comprising a magnetic core 13 carrying at one end 13b, a laminated lobe-shaped pole member 14 co-operating with polyphase stator windings 11, and at the other end a cylindrical part 13a extending into an axial exciting coil 12. The laminated stator 15, which has skewed slots for smooth operation, has a magnetic end-bell extension 27 which is provided with an aperture 31 closely spaced from the part 13a of the rotor core. The other end of the stator carries a non-magnetic end-bell 61 in which the bearing 65 is secured. The core 13 is made of soft iron e.g. 2 per cent silicon iron or compressed powdered iron and is provided with axial slots 81 to reduce eddy-currents. In order to produce an induced voltage in the winding 11 of suitable, e.g. sinusoidal wave-form, the lobed rotor 14 is shaped to produce a sinusoidal flux distribution. Two- and four-pole rotors are shown in Figs. 4 and 5 respectively, figures defining the profiles being given. When the machine is to be operated as an alternator, the exciting winding 12 is. fed with D.C., but when required for use as a selsyn it is fed with A.C., the threephase stator windings being interconnected in the usual way. It is described how the machine may be excited with saw-- tooth modulated current to produce a spiral scan in the cathode-ray used in an echo-ranging system (see Groups XXXVI. and XXXVIII).