Nikola Tesla Books
KICKING COIL APPARATUS 79 12 rosin; in this compound suspend the condenser units for two hours. If the wax has been kept sufficiently hot the interstices between the glass plates will be completely filled and each unit will form a homogeneous mass that is both electrically and mechanically sound on cooling. The Oscillation Transformer.-This may be either of the Oudin or the Tesla type. For the sake of simplicity, the former is preferable. In order that the fullest benefit may be derived from the exciting apparatus it is essential that the primary and secondary of the oscillation transformer be closely coupled. This is effected by means of the spirally-wound or "pancake" type of Oudin coil.. This coil is wound in a succession of layers in flat or pancake form as its name implies. The wire is No. 30 D.C.C. and the insulating material between layers of wires is oiled paper 1½ in. wide and .003 thick. The post shown in Fig. 7 is of hard rubber. While the rod is held in the chuck a 4 in. hole is drilled clear through. The tail stock center is then brought up to bear in the hole to prevent chattering and the end of the post is finished off. A cut-off tool introduced at the correct position finishes the rubber rod. The hole at the base of the rod is to be tapped out -18. A length of 1/4 in. brass rod is then forced in from the top of the post and cut off when it has entered to within 1½ in. of the base. The top is threaded to enter a discharge ball and near the bottom a small hole is drilled through the hard rubber rod and into the brass to take an escutcheon pin which forms a means of connection. The rubber post is then to be screwed on to an arbor threaded -18 with a large disc of metal or wood between. Upon this rig, the pancake coil is to be wound. The winding may be done either in the lathe or, if none is available, in a simple, home-made winder. The
