Accelnet Plus Micro Modules User Guide
16-01687 Rev 03
Copley Controls
Page 40 of 139
DC
P
OWER
G
ROUNDING
The graphic below shows the basic elements of a DC power supply system for a Plus Micro
Module drive. The Plus Micro Module drives are Protective Class I equipment in regards to
protection against electric shock. Accordingly, the drives have both basic insulation
between circuits and accessible conductive parts and a means of connecting a protective
earthing conductor to prevent accessible conductive parts from becoming hazardous live
in the event of a failure of the basic insulation. A protective earthing conductor must be
connected to the drive at the grounding point on the drive marked with the PE (Protective
Earth) symbol. Note that the Plus Micro Module drives require that the DC power supply
be galvanically isolated from AC mains as shown in the figure below.
The PE marking is shown to illustrate the point for connecting the protective earth
conductor to the drive. Aside from the electrical safety aspects of grounding, attention
must also be paid to the wiring and grounding practices required to reduce susceptibility
to external EMI (Electro-Magnetic Interference) sources, to suppress EMI emissions, and
to minimize differences in signal grounds due to cable length and equipment connections.
The (-) terminal of the power supply is connected by a short, direct path to the equipment
ground terminal (sometimes called the “star” or equipment ground). This practice is
common when drives are in the same cabinet with short connections to the drives.
The DC power wiring is shown as a shielded, twisted pair of a gauge suitable for the input
current rating of the drive. The shield should connect to the (-) terminal of the power
supply on one end, and to a screw that holds the heatplate to the mounting plate for best
results. This connection will provide the lowest impedance path between the power supply
and drive for noise originating in the drive. Doing so will minimize noise currents flowing
in the mounting plate or the cabinet.
V
VCOM
eatplate
V OGIC
1 6
1
Equipment Ground
Standoff
N
Gnd
Gnd
.G.
AEV APV
1
rame
Ground
PE V SE V
N
.G.
.G.