GB518863A - Dynamometer - Google Patents

Abstract

518,863. Rotary - absorption dynamometers. WINTHER; M. P. June 7, 1938, No. 16915. Convention date, March 17. [Class 106 (ii)] [Also in Group XXXIV] Relates to the type in which a rotor and stator are magnetically coupled and one of the members is provided with flux concentrating means, and includes in association with the other member, a separate element adjacent the flux concentrating means providing passages for cooling fluid. A shaft 1 supports a keyed rotor 3 having flux concentrating teeth 5 and rotates in bearings 7, in the stator case 9, supported in bearings 11 in the pedestal 13. The case has side members formed by brass spiders 17 having ventilation openings 21. The outer members 19 are bolted together and grip a coil 37 having a metal sheath. The teeth 5 draw in air at openings 21 and expel it through openings 35, 39. When the coil is excited a field of flux is generated so that when the part 3 rotates eddy currents are induced in the stator 9. The torque reaction is measured by a weighing machine the platform of which is engaged by an arm attached to the case 9. Each casting 19 is machined internally and fitted with a forged stator ring 49 provided with water passage grooves 51. The ring is also preferably provided with a thin copper insert 53. The rings 49 are welded at the ends engaging the part 19. Grooves are machined on the inside of the insert 53 or on the rings 49 to relieve expansion stresses. Asbestos packing rings and shrouds may be used instead of welds. In a modification disc-like rings are substituted for the ring 49. The stator casings 19 are formed at the upper portion with bores 73, 75 provided with cover plates 77, 79. The box 73 is divided by partitions 81, 83 to form three compartments 85, 87 and 89. A cold water pipe 103 supplies water to the inlet 105 of compartment 85. The water flows clockwise around channels 51 into compartment 87 and through channels to 89 and hence to outlet 107 and pipe 109 to the inlet 111 for box 75, ultimately escaping at 113. The water is also forced to circulate through the machined steel rings.