United States Navy Aviation Mechanics' Training System for Engine Maintenance Force; Course Manual for Machinist's Mates' (A) (Advanced) Course (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...the core. The resulting decreased magnetic pull will not be sufficient to hold the armature against the opposing tension of the spring, and the contacts will close. The non-inductive resistance adds resistance to the field circuit when the contacts open and also absorbs the energy which would otherwise cause a spark at the contacts. In this respect the non-inductive resistance performs the function of a condenser. The distance between the contact points is adjustable and should be from.005 to.007 in., preferably.006 in. This adjustment affects the voltage at which they open, for the air gap at the core is equal to the gap at the points. The greater the gap at the points the higher the generator-terminal voltage when the points open. The fixed contact is insulated from the regulator frame by means of a strip of insulation under the contact clip. This is shown hatched in Fig. 255. The spring tension, which is also adjustable, affects both the opening and closing of the contact points. The greater the spring tension, the higher the voltage at which the contact points open and close. This is the only adjustment affecting the closing of the points. The adjustment is made by means of the knurled nut shown in Fig. 255. The adjustment of the regulator is a bench job. The generator and regulator are connected together as in normal operation, the specified cable and lugs being used. Then the generator is driven with no load at 3,000 r.p.m. The contact gap is adjusted to from.005 to.007 in. and Fig. 256.--Liberty voltage regulator. the spring tension is then adjusted until the generator voltage is 10.0 volts. Fig. 256 shows the Liberty regulator complete, as assembled, front view and side view, the latter showing part of the aluminum regulator housing cut-away. 181. S...