Motors and generators

46 CFR §111.12-11

§ 111.12-11 -11 Generator protection. (a)This section applies to each generator except a propulsion generator. (b)Each ship's service generator and emergency generator must be protected by an individual, tripfree, air circuit breaker whose tripping characteristics can be set or adjusted to closely match the generator capabilities and meet the coordination requirements of Subpart 111.51. Each circuit breaker must contain the trips required by this section. (c)A circuit breaker for a generator must: (1) Open upon the shutting down of the prime mover; (2) Have longtime overcurrent trips or relays set as necessary to coordinate with the trip settings of the feeder circuit breakers; and (3) Not have an instantaneous trip with the exception that an instantaneous trip is required if: (i) T…

46 CFR §111.25-1

§ 111.25-1 -1 General requirements. The requirements for generators contained in § 111.12-5 apply to motors. [CGD 74-125A, 47 FR 15236, Apr. 8, 1982, as amended by CGD 94-108, 62 FR 23908, May 1, 1997]

46 CFR §111.25-15

§ 111.25-15 -15 Duty cycle. Each motor must be rated for continuous duty, except a motor for an application listed in Table 111.25-15 or a similar duty must meet the minimum short-time rating stated in the table. Table 111.25-15 Application of motor | Minimum short-time rating of motor, in hours Deck winch and direct acting capstan | Half. Deck winch with hydraulic transmission | Continuous at no load followed by⁄hr. at full load. Direct acting windlass | One fourth. Windlass with hydraulic transmission | Half hour idle pump operation, followed by⁄hr. full load operation. Steering gear, direct acting | One. Steering gear, indirect drive | Continuous operation at 15 pct. load followed by 1 hr. at full load. Watertight door operators | ⁄. Boat winches | ⁄.

46 CFR §111.50-1

§ 111.50-1 -1 Protection of equipment. Overcurrent protection of electric equipment must meet the following listed subparts: (a) Appliances, subpart 111.77. (b) Generators, subpart 111.12. (c) Motors, motor circuits, and controllers, subpart 111.70. (d) Transformers, subpart 111.20. [CGD 74-125A, 47 FR 15236, Apr. 8, 1982, as amended by USCG-2020-0075, 88 FR 16362, Mar. 16, 2023]

46 CFR §111.51-2

§ 111.51-2 -2 Short-circuit calculations. (a) The available short-circuit current must be computed— (1) From the aggregate contribution of all generators that can simultaneously operate in parallel; (2) From the largest probable motor load; and (3) With a three-phase fault on the load terminals of the protective device. (b) The calculated currents must be used to select suitably rated equipment and to allow the selection and setting of protective devices.

46 CFR §111.70-1

§ 111.70-1 -1 General. (a) Each motor circuit, controller, and protection must meet the requirements of sections 4-8-2/9.17, 4-8-4/9.5 and 4-8-3/5 of ABS Marine Vessel Rules; sections 6-1-7/9.9 and 6-1-7/9.15 of the ABS MOU Rules; or IEC 60092-301:1980 (all three standards incorporated by reference; see 46 CFR 110.10-1), as appropriate, except for the following circuits: (1) Each steering gear motor circuit and protection must meet part 58, subpart 58.25, of this chapter. (2) Each propulsion motor circuit and protection must meet subpart 111.35 of this part. (b) In ungrounded three-phase alternating current systems, only two motor-running protective devices (overload coil or heater type relay within the motor and controller) need be used in any two ungrounded conductors, except when a …