GB557552A - Improvements in or relating to apparatus for checking the power generated by small electric motors - Google Patents

Abstract

557,552. Testing motors. SELF-PRIMING PUMP & ENGINEERING CO., Ltd., and WATSON, F. J. April 23, 1942, No. 5482. [Class 37] Testing apparatus is arranged for rapidly checking whether or not the power generated by a small motor reaches the prescribed standard when the motor is run at its prescribed speed. A base 10 supports a plate 11 on one end of which is mounted an eddy-current generator 12. This has a solid copper armature 13, or a squirrel-cage rotor, the field circuit 30, Fig. 3, being supplied from an A.C. source 31 and controlled by a rheostat 32 and a hand-operated switch (not shown). The motor 14 to be tested is supported in a V-block 15 with its shaft in alignment with the armature shaft of the generator. The block 15 is adjustable along the plate 11 for testing motors of different sizes and is locked in adjusted position by a set-screw 16. The shaft of the motor 14 is coupled with the shaft of the armature 13 by a flexible coupling 17. The motor 14 is supplied with current controlled by a handoperated switch. In parallel with the field of the generator 12 is a polarized relay 18 controlling red and green indicator lights 19, 20 mounted on a sloping panel 22. A stroboscope (not shown) is arranged to indicate when the motor is running at the prescribed speed. The field of the generator 12 is adjusted until the speed is correct, the field current then being a function of the power of the motor under test. The relay 18 closes the circuit of one or other of the indicating lamps 19, 20 according as the power is above or below the predetermined standard. The apparatus is also applicable for testing small motor car or other engines. Specification 557,551, [Group XX], is referred to.