E300 Installation and Commissioning Guide
85
Issue Number: 1
4.17.7 Interruptions to the motor cable
The motor cable should ideally be a single length of shielded or armored cable having no interruptions. In some situations it may be necessary to
interrupt the cable as shown in the following examples:
•
Connecting the motor cable to a terminal block in the drive enclosure
•
Installing a motor isolator / disconnect switch for safety when work is done on the motor
In these cases the following guidelines should be followed.
Terminal block in the enclosure
The motor cable shields should be bonded to the back-plate using un-insulated metal cable-clamps which should be positioned as close as possible
to the terminal block. Keep the length of power conductors to a minimum and ensure that all sensitive equipment and circuits are at least 0.3 m (12 in)
away from the terminal block.
Figure 4-38 Connecting the motor cable to a terminal block in the enclosure
Using a motor isolator / disconnect-switch
The motor cable shields should be connected by a very short conductor having a low inductance. The use of a flat metal coupling-bar is
recommended; conventional wire is not suitable. The shields should be bonded directly to the coupling-bar using un-insulated metal cable-clamps.
Keep the length of the exposed power conductors to a minimum and ensure that all sensitive equipment and circuits are at least 0.3 m (12 in) away.
Figure 4-39 Connecting the motor cable to an isolator / disconnect switch
4.17.8 Surge immunity of control circuits
The input/output ports for the control circuits are designed for general use within machines and small systems without any special precautions. These
circuits meet the requirements of EN 61000-6-2:2005 (1 kV surge) provided the 0 V connection is not grounded. In applications where they may be
exposed to high-energy voltage surges, some special measures may be required to prevent malfunction or damage. Surges may be caused by
lightning or severe power faults in association with grounding arrangements which permit high transient voltages between nominally grounded points.
If a digital port experiences a severe surge its protective trip may operate (I/O Overload trip). For continued operation after such an event, the trip can
be reset automatically by setting
Number Of Auto-reset Attempts
(
H46
) > 0.
Figure 4-40 Surge suppression for digital and unipolar inputs and outputs
From the Drive
To the motor
Back-plate
Enclosure
Isolator
Coupling bar
From the
Drive
To the
motor
(If required)
Signal from plant
Signal to drive
0V
0V
30V zener diode
e.g. 2xBZW50-15
Содержание E300 Series
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