Page 218 - Electromechanical Devices and Components Illustrated Sourcebook

180 Electromechanical Devices & Components Illustrated Sourcebook

the same method as the V-notch unit, except that they have Beryllium Copper
several specific wire size locations in the jaws. These are par- Leaf Spring Terminal
ticularly useful in situations where a technician is working
with several different sizes of wires. Automatic wire strippers
Rotating Hub Electrical Feed
are generally used in production stripping. The wire is placed
into the jaws, a quick squeeze of the handle, and the wire is
stripped and ejected in one quick operation. Thermal wire Axle
strippers are generally used on outer jackets of multiconduc- Machine Frame
tor cables or in applications where it is critical that the con- Figure 10-35 Leaf Spring Rotary Conductor
ductor is not nicked. The jaws are closed onto the insulator,
the plastic is weakened, and the insulation is pulled off. The
temperature of the stripper is adjusted to match the material
Leaf spring rotary conductors are the classic design. They
from which the insulation is made.
provide moderate current-carrying capacity at low to medium
speeds and they are simple to build and service. Multipole
arrangements can be set up by simply adding additional
Rotary Conductors hub/spring sets. Figure 10-35 shows a typical leaf spring
rotary conductor.
Making an electrical connection through a rotating axle is a
Wire brush rotary conductors are similar to their leaf spring
difficult proposition. However, there are many applications
counterpart. The principal difference is that the leaf spring is
for such connections, the most noteworthy being the armature
replaced with a brass wire brush. These conductors provide
on a DC motor.
low current capacity at medium to high speeds. Because of the
Figure 10-33 shows a high-current, low-speed, slip ring
multiple contacts that are made by the individual wires, these
rotary conductor. These units consist of a rotating brass hub
conductors have very consistent conductivity. Figure 10-36
with a preloaded brass block in contact. The interface is lightly
shows a view of a wire brush rotary conductor.
oiled to minimize wear. This type of slip ring is commonly
used to connect welding currents to a rotating assembly.
Multipole plate rotary conductors as shown in Figure 10-34,
Brass Brush
can be used for moderately high currents and medium speeds.
Terminal
The preload spring is adjusted to assure contact. The disk
plates are lightly oiled for low speeds and use conductive Rotating Hub
grease for higher speeds. Electrical Feed
Axle
Preload Spring Insulating Collar
Brass Hub Guide Rod Machine Frame
Axle Terminal Figure 10-36 Wire Brush Rotary Conductor

One of the most common rotary conductors is the carbon
Brass Block brush set. This type of conductor is found in nearly every uni-
Feed Wire
Machine Frame versal and DC motor manufactured today. These conductors
provide moderate current-carrying capabilities at medium to
Figure 10-33 Slip Ring Rotary Conductor high speeds. The design consists of a rotating brass hub which
has a carbon/graphite block forced into it by a preload spring.
The block rides in a brass housing that doubles as the electri-
cal terminal. Figure 10-37 shows a sectional view of a typical
Registration Pin carbon brush rotary conductor.
Preload Spring
Insulating Collar
Load Spreader
Fixed Disks Insulating Body
Inputs Brass Button
Rotating Disks Preload Spring
Insulators Rotating Hub
Threaded Cap
Rotating
Axle
Assembly
Machine Frame
Carbon/Graphite Block
Brass Housing
Figure 10-34 Multipole Plate Rotary Conductor Figure 10-37 Carbon Brush Rotary Conductor