Naval Electricians' Text Book ..., Volume 2

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Page 31 - Between adjacent electric circuits, where such exist, as in transformers. The tests should be made, with a sine wave of emf, or where this is not available, at a voltage giving the same striking distance between needle points in air, as a sine wave of the specified emf, except where expressly specified otherwise. As needles, new sewing needles should be used.
Page 721 - ... or combined capillarity and viscosity to keep the surfaces between which it is interposed from coming in contact under maximum pressure. (2) The greatest fluidity consistent with the preceding requirements, ie, the least fluid-friction allowable.
Page 801 - YY, through its center of gravity, and carried by the frame or vertical ring D. The ring D is suspended by the tortionless strand E, and guided by bearings ZZ' to allow a free oscillation of limited amount about its vertical axis ZZ' within the frame or phantom G.
Page 803 - ... and a cam P forming part of the automatic correcting device. The power drive is also utilized in operating the transmitter for the repeater instruments, and in overcoming friction of the slip rings needed to carry current to the gyro. Since the phantom G, though at all times rigidly anchored to the binnacle, stands in practically constant relation to the sensitive element...
Page 700 - Nothing is gained by increasing the pressure per square inch on a carbon brush above 2 pounds, as the resistance per square inch beyond this point is practically not reduced, whereas the friction is increased in direct proportion to the pressure. Fit the carbon brushes carefully to the commutator by passing beneath them No. 0 sandpaper, with the rough side against the brush and the...
Page 52 - A waterproof machine is a totally enclosed machine so constructed that a stream of water from a hose (not less than 1 inch in diameter) under a head of 35 feet and from a distance of about 10 feet can be played on the machine...
Page 47 - Variation to be not more than 4 volt per step at both full and half load. OPERATION OF GENERATOR. The compounding to be such that with turbine working within specified limits, field rheostats and brushes in a fixed position, and starting with normal voltage at no load or at full load, if the current be varied step by step from no load to full load, or from full load to no load, and back again, the difference between maximum observed voltage and minimum observed voltage shall not exceed 2\ volts.
Page 30 - In sizes over 5 kw there shall be not less than two brushes per stud, each brush to be separately removable and adjustable without interfering with any of the others. The point of contact on the commutator shall not shift by the wearing away of the brush. Brush holders to be staggered in order to even the wear over entire surface of commutator ; the generator to be provided with some device for shifting all the holders simultaneously. All insulating washers and brushes to be damp proof and unaffected...
Page 369 - The speed variation must not exceed 2% when load is varied between full load to 20% of full load, gradually or in one step, engine running with normal steam pressure and vacuum. A variation of not more than 3J...
Page 31 - The dielectric strength or resistance to rupture should be determined by a continued application of an alternating emf for one minute. The source of alternating emf should be a transformer of such size that the charging current of the apparatus as a condenser does not exceed 25 per cent, of the rated output of the transformer.

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