1-6
Wire/Cable Types
Type 3 Installation
Type 3 installation requires 3 symmetrical ground conductors whose
ampacity equals the phase conductor. Refer to
detailed information and specifications on this installation.
Figure 1.6 Type 3 Unshielded Multi-Conductor Cable
The outer sheathing and other mechanical characteristics should be chosen
to suit the installation environment. Consideration should be given to
surrounding air temperature, chemical environment, flexibility and other
factors as necessary in all installation types.
Shielded Cable
Shielded cable contains all of the general benefits of multi-conductor cable
with the added benefit of a copper braided shield that can contain much of
the noise generated by a typical AC Drive. Strong consideration for shielded
cable should be given for installations with sensitive equipment such as
weigh scales, capacitive proximity switches and other devices that may be
affected by electrical noise in the distribution system. Applications with
large numbers of drives in a similar location, imposed EMC regulations or a
high degree of communications / networking are also good candidates for
shielded cable.
Shielded cable may also help reduce shaft voltage and induced bearing
currents for some applications. In addition, the increased size of shielded
cable may help extend the distance that the motor can be located from the
drive without the addition of motor protective devices such as terminator
networks. Refer to
for information regarding reflected wave
phenomena.
Consideration should be given to all of the general specifications dictated by
the environment of the installation, including temperature, flexibility,
moisture characteristics and chemical resistance. In addition, a braided
shield should be included and specified by the cable manufacturer as having
coverage of at least 75%. An additional foil shield can greatly improve
noise containment.
G
R
B
W
G
G
Filler
PVC Outer
Sheath
Multiple Ground
Conductors
Summary of Contents for Allen-Bradley 1305-AA02A
Page 4: ...ii Summary of Changes Notes ...
Page 40: ...2 18 Power Distribution Notes ...
Page 48: ...3 8 Grounding Notes ...
Page 68: ...4 20 Practices Notes ...
Page 78: ...6 8 Electromagnetic Interference Notes ...
Page 94: ...Glossary 4 UL Underwriters Laboratories ...
Page 100: ...Index 6 ...
Page 101: ......