Brushes used in generators are manufactured from what material?
What function do the brushes in a generator serve?
They provide a passage for the electrical current to an internal or external circuit
What connects the brushes to the terminals of the external circuit?
What is used to maintain good contact between the brushes and slip rings?
Brush grade is determined by using what technical guidance?
Drawings or technical manuals.
Who issues special instructions that supersede drawings or technical manuals when determining brush grade?
Naval Sea Systems Command.
What must be done to a brash that is worn to 40 percent or less of the original length?
When measuring the pressure of brushes operating in box-type brush holders what is inserted between the brush and slip ring?
A strip of paper.
When measuring the pressure of brushes operating in a box type brash holder, what is used to exert a pull on the brash in the direction of the brash holder axis?
A small brush tension gage.
How do you read the small brush tension gage?
The gage is read when the pull is sufficient to release the strip of paper. This reading is divided by the contact area, thus giving the unit operating pressure.
Brash holders should have what minimum distance from the commutator?
What is the maximum allowable distance a brash holder can have from the commutator?
How do you check the brashes for even spacing around the conunutator?
By wrapping a strip of paper around the commutator and mark the paper where the paper laps.
If brashes are incorrectly staggered what effect will occur?
Grooving of the commutator.
Brashes that are newly installed which do not fit properly, can be corrected by what method?
By using sandpaper.
Brashes are checked for proper seating and freedom of movement at what periodicity?
How many military grades of brushes exist?
What will happen if brushes are mismatched during installation?
Rapid brush wear will occur.
Brushes that have riveted connections or hammer clips must be replaced when worn to what degree of the metallic part?
1/8 inch of the metallic part.
When must brushes having spring enclosed shunts be replaced due to wear?
When worn to 40 percent or less of the original length of the brush exclusive of the head which fits into one end.
What is the wear replacement criteria for brushes having tamped connections and without hammer clips?
When they are worn to one-half or less of the original length of the brush.
What type of brush spring is non-adjustable?
Coiled-band, constant-pressure type.
All brush holders must be within what distance from the commutator?
Not more than 1/8 inch nor less than 1/16 inch, unless specified by the manufacturer.
What is used to fit and seat new brushes?
What is the recommended grade of sandpaper to be used when seating brushes?
Medium (80 grit).
Pulling the sandpaper from under the brushes will have what effect on the seating surface?
It will cause rounding, scratch the brash surface and unnecessarily contaminate components with carbon dust.