The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 10, 1981
Filed:
May. 28, 1980
Hisayoshi Monma, Katsuta, JP;
Shigenobu Katagiri, Katsuta, JP;
Hitachi Koki Company, Limited, Tokyo, JP;
Abstract
A failure detection circuit for stepping motors having a rotor and a motor control circuit including first and second transistors respectively connected in series with first and second stator coils. The rotor is set in motion in response to energization of the second stator coil when the second transistor is activated and brought to a halt in response to energization of the first stator coil when the first transistor is activated. During the interval when the first transistor is activated, the potential at a circuit junction between the respective transistor and the associated coil is detected and compared with the logic level of the input to the associated transistor to check for a set of operational states of the circuit elements to give a warning indication if the compared levels have a predetermined relationship to each other. During the interval when the rotor is at standstill, the second transistor is activated in a brief interval so that the amount of current generated in the second stator coil is insufficient to generate a torque to the rotor and in this brief interval the above comparison is made to check for another set of operational states of the circuit elements to give a warning indication if the compared levels have a predetermined relationship therebetween.