CONNECTIONS FOR THE SIX-POLE ARMATURE
The inside terminal of coil A and the inside terminal of coil B should be connected to section 2, the outside terminal of coil C and the outside terminal of coil D should be connected to Section 3, the outside terminal of coil E and the outside terminal of coil F should be connected to Section 1, the outside terminal of coil A and the inside terminal of coil C should be connected to Section 1, the inside terminal of coil D and the inside terminal of coil E should be connected to Section 2, the inside terminal of coil F and the outside terminal of coil D should be connected to Section 3.
FIG. 67.—The Brushes and Brush Holder.
The wires leading from the coils to the commutator should be just as short as it is possible to make them and after being soldered should be bound down tightly with linen thread or string.
The bearings are both cast from brass. The details are shown in Figure 66 It will be necessary to make up wooden patterns and send them to a foundry. The location of the holes can be ascertained from the illustration.
FIG. 68.—Details of the Field Frame for the Horizontal Power Motor.
Each of the brushes consists of a piece of strip copper, one-quarter of an inch wide and one and three-eighths inches long mounted in a brush holder made of one-quarter inch brass rod. The brush holder is one inch long and is turned down to a diameter of one-eighth of an inch at one end for a distance of nine-sixteenths of an inch and then threaded with a 6-32 die. The opposite end is slotted to receive the brush. The threaded portion of the holder is slipped through the holes, "B and B", in the bearing and prevented from making contact with the latter by a fibre bushing.
FIG. 69.—Front view of the Field Frame.
FIG. 70.—The Field Magnet Bobbin.
A fibre washer should also be slipped over the holder on each side of the bearing. Two hexagonal nuts are placed on the threaded stem. One serves to clamp the holder in position and the other to hold the wire used to make connection with the brush. The right hand brush should bear against the under side of the commutator and the left hand brush against the upper side.
After the armature has been assembled in the bearings and mounted on the field frame it should revolve freely without friction and without any possibility of its striking against the field poles.
The binding posts are mounted in the holes, "PP" in the lower parts of the field frame. They are insulated by two fibre or paper busings. The left hand binding post is connected to the inside terminal of the field winding. The outside terminal of the field winding is connected to the left hand binding post. The right hand binding post is connected to the right hand brush.
The base of the motor is a wooden block of suitable size.
FIG. 71.—Details of the Shaft, Rocker Arm, Bearing and Pulley.
The motor is of the series type because all the current flows through both the field and armature. A current of 2 to 6 volts will operate the motor. The pulley or gear required in order that the motor may be used as a source of power will depend upon the work for which the motor is to be employed. A small grooved pulley such as as that shown in Figure 63 may be fastened to the shaft with a set screw and will prove most useful for general purposes.