INSTALLATION AND OPERATION
SX TRANSISTOR CONTROL
Page
13
•
Control common tie
•
DC buses feeding sensitive analog or digital hardware
•
All wiring connected to components associated with
sensitive analog hardware with less than 5V signals (for
example, potentiometers and tachometers)
•
Digital tachometers and resolvers
•
Dash display cabling
•
RS-232 cabling
Note:
Signal inputs to analog and digital blocks should be
run as shielded twisted-pair (for example, inputs from
tachometers, potentiometers, and dash displays).
4.2.2.b High-Level Signals (Level H)
High-level signals are designated as
level H
. These signals
consist of:
•
Analog and digital signals greater than 15 V DC and
less than 250 mA
For example, switch inputs connected to battery volts are
examples of level H signals used in drive equipment
cabling.
4.2.2.c Medium-Power Signals (Level MP)
Medium power signals are designated as
level MP
. These
signals consist of:
•
DC switching signals greater than 15 V
•
Signals with currents greater than 250 mA and less than
10A
The following are specific examples of level MP signals
used in drive equipment cabling:
•
DC busses less than 10 A
•
Contactor coils less than 10 A
•
Machine fields less than 10 A
4.2.2.d. High Power Signals (Level HP)
Power wiring is designated as
level HP
. This consists of DC
buses and motor wiring with currents greater than 10 A.
The following are specific examples of level HP signals
used in drive equipment cabling:
•
Motor armature loops
•
DC outputs 10 A and above
•
Motor field loops 10 A and above
4.2.3. Cable Spacing Guidelines
Recommended spacing (or clearance) between cables (or
wires) is dependent on the level of the wiring inside them.
For correct level separation when installing cable, the
and prevents damage caused by electrical surges.
controlled by an output. This
suppression minimizes noise
example, a snubber) is required on all inductive devices
Unless specifically noted otherwise, suppression (for
Section 4.2.6 Suppression
controlled devices.
be taken in routing power cables in the vicinity of radio-
To prevent radio frequency (RF) interference, care should
4.2.5 RF Interference
HP wires.
Do not loop level L signal wires around level H, level MP, or
minimize noise potential.
For level L wiring, use barriers in existing wire runs to
separate from existing cables, whenever possible.
noise producing. Therefore, route levels L and H in a path
Existing cables are generally
of high voltage potential and
the full length of the run.
the level spacing (see section 4.2.2) can be maintained for
It is practical to use existing wire runs or trays as long as
encircle each other or run parallel for long distances.
careful planning. Lower and higher levels should never
Reducing electrical noise on vehicle retrofits requires
4.2.4 Cabling for Vehicle Retrofits
between unlike levels at the crossover point.
to maintain spacing, place a grounded steel barrier
angles at a maximum spacing.
Where it is not possible
•
When unlike signals must cross, cross them in 90°
together with twine or zip-ties.
together in multiconductor cables or bind them
those wires from one location to any other location
•
If wires are the same level and same type signal, group
designation.
•
Interconnecting wire runs should carry a level
exception.
above. Intermixing cannot be allowed, unless noted by
bundles, as defined in the different classes, identified
•
In general, different levels
must run in separate wire
levels must be grouped together.
•
All cables and wires of like signal levels and power
levels
of cabling:
The following general practices should be used for
all
4.2.3.a General Cable Spacing
4.2.3.a), outlined below.
customer must apply the
general guidelines
(section
Updated Sept 2019
