MIL-DTL-6162 Generators And Starter-Generators, Electrical Direct Current, Nominal 30 Volts, Aircraft General Specification ForThis specification covers the general requirements for aircraft generators and starter-generators for use in 28-volt \(V\) direct current \(DC\) systems. As generators, both type machines are engine driven. The starter-generators, however, also function as engine starters when energized by electric power.

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MIL-DTL-6162C

3.4.5.9 Shaft deflection. The machine shall be designed to operate with the drive shaft in misalignment to the

maximum allowable limits specified for the mating engine accessory drive (see 4.6.1).

3.4.5.10 Electrical connections. For brush type machines, the internal wiring of the machine shall be in

accordance with Figure 4. Terminations shall be as shown on the associated specification sheet. Connectors and

leads shall be secured in a reliable manner to prevent contact with moving parts or chafing by contact with stationary

parts. All leads shall be permanently marked with the designating letters. For other than shunt wound machines,

reference shall be made to the associated specification sheet (see 4.6.1).

3.4.5.11 Terminal block design. Where terminals are used for the external connection, they shall be of the

stud-type and shall be designed so that the current is conducted by means of surface to surface contact and not

through the stud. All studs shall be steel, corrosion resistant and C-34 Rockwell minimum hardness. All nuts by

which external wiring is attached to a component shall conform to MIL-DTL-25027. Threads on studs and nuts shall

conform to MIL-S-8879 or current industry practices (see 3.9). There shall be no compression of the insulating

material when assembled. The terminal block shall be so designed that it can be removed and replaced on the

machine without the necessity for re-brazing or soldering. Barriers affording a positive separation of leads and

terminals shall be provided on the terminal block. Terminal designations shall be durably, legibly, and prominently

marked on the terminal block. Terminals shall be provided with a durable, reusable cover and wire fanning strip to

prevent interchanging connections.

3.4.5.12 Terminal block location. The terminal block shall be located and marked as shown on the associated

specification sheet.

3.4.5.13 Brushes and brush holders (for brush type machines). The following requirements shall apply to

brushes (see 4.6.1) and brush holders.

3.4.5.13.1 Accessibility. Brushes shall be readily accessible for inspection and replacement when brush cover is

removed.

3.4.5.13.2 Fit. After seating, the face of each brush shall contact its commutator 100 percent. There shall be no

evidence of surface damage to the face of the brush or commutator. Commutation shall be such that no more than

1� sparking is in evidence as shown in Figure 5.

3.4.5.13.3 Brush type. Unless otherwise specified by the procuring activity, brushes shall be of the immediate

filming type, which do not require prolonged operation of the machine at sea level to establish an altitude protective

film on the commutator. In any event, machines shall be supplied with the necessary filming. Rivets used to secure

the leads to the brushes shall be silver soldered to the pigtail at the point of riveted contact using an alloy with a

minimum melting point of 1000� F.

3.4.5.13.4 Brush rigging. Brush rigging shall be a fixed position (unshift) type with respect to the field

structure. The brush rigging shall be permanently pinned during manufacture, and shall be identical and completely

interchangeable for all generators of the same part number made by the same manufacturer. The brush rigging shall

be so mounted and aligned that brushes are parallel to the shaft. Proper running clearance between the rigging and

commutator face and risers shall be maintained. The brush rigging shall be of such a design that brushes will not

bind. Contact surfaces shall be of such material as to not react chemically to produce corrosion and sticking of

brushes. The brush-feeding device shall insure proper brush pressure and contact during all normal conditions of

brush and commutator wear including any commutator which have been turned to the minimum allowable diameter.

Brush springs shall be self-centering or the brushes shall provide spring guides.

3.4.5.13.5 Spare brushes. All spare and replacement brushes shall be formed to a radius equal to the radius of

the new commutator and shall be the qualified brushes. The brushes shall be packed in kit form (complete set for

one generator) with installation instructions packed with each kit.

3.4.5.13.6 Brush marking. Each brush shall have a diagonal groove extending from one corner of the brush

face to a point at the brush back or front, which indicates 100 percent allowable, wear.