Method of and apparatus for testing and adjusting d.c. rotary machines
OwnerNicholas N. Riverainventor
Life of this patent
Estimating the term…
Abstract
Apparatus may be inserted in the casing of a d.c. motor or a d.c. generator for measuring not only the magnetic fields prevailing in the machine but developing other useful information. The magnetic fields between the field poles and the armature, and also the armature/mmf fields aligned with the brushes may be measured. The measurements of the fields permits a complete plot of the fields in the machine and also permits a test to be performed to see if the brushes are at their optimum positions. If a brush is not at its optimum position, the brush may be shifted back and forth until the maximum mmf, due to the current through the armature is aligned midway between the leading and trailing ends of the brush area coverage on the commutator.
Claims20
The combination of a d.c. machine and apparatus responsive to the magnetic fields in the machine, comprising:
- said d.c. machine having (a) casing, (b) a rotatable element located in said casing and having an axis of rotation, the rotatable element including a commutator and an armature, (c) means in said casing for applying a magnetic field to said armature and (d) brushes contacting the periphery of said commutator,
- a probe inside of said casing, for sensing magnetic fields,
- at least one of said brushes being adjustable around said periphery independently of at least another one of said brushes,
- said apparatus including means in said casing, for moving said probe adjacent said one of said brushes and about said axis, in a substantially arcuate path that is in a plane perpendicular to said axis, and
- means responsive to said probe for indicating variation in the field sensed by said probe.
The method of sensing magnetic fields in a d.c. machine, comprising:
- providing said machine with an armature, a commutator, field poles and brushes, with said armature and said commutator having an axis of rotation,
- providing a probe for sensing magnetic fields,
- providing a casing that encloses said probe, said armature, said commutator, said field poles and said brushes,
- moving said probe adjacent at least one of said brushes about said axis in a substantially arcuate path, that is perpendicular to said axis, and
- giving an indication of the strength of the field sensed by said probe.
The method of adjusting the brush on a d.c. machine, comprising:
- providing said machine with a commutator whose outer surface is substantially cylindrical,
- providing said machine with risers which taken as a group have a substantially cylindrical outer surface,
- providing a probe that is movable back and forth adjacent said brush and near to said surface of said risers,
- providing an indication that varies with the magnitude of the magnetic flux passing through said probe, and
- moving one or both of the probe and the brush until the probe is positioned to sense the maximum flux and the brush is on a line that is parallel to said axis and which substantially intersects a line that intersects both said probe and said axis.
The combination of a d.c. machine and apparatus responsive to magnetic fields produced by the machine, comprising:
- said d.c. machine having (a) a casing, (b) rotating means in said casing and having an axis of rotation, (c) field poles in said casing and (d) a brush in said casing;
- said rotating means comprising an armature, risers and a commutator having a periphery, said field poles passing a magnetic field through said armature,
- a probe inside of said casing, for sensing magnetic fields,
- said probe having an output,
- said apparatus including means for moving said probe adjacent said brush and about said axis,
- means responsive to the output of said probe for converting the output of the probe into an indication of the amplitude of the magnetic field intercepting said probe, and
- holding means for holding said brush in a cooperative relation with said commutator and for enabling the position of the brush along said periphery to be adjusted.
Dependencies are inferred from the claim text.