Q9 Plus ASD Installation and Operation Manual
17
System Grounding
Proper grounding helps to prevent electrical shock and to reduce electrical noise. The
Q9 Plus ASD
is
designed to be grounded in accordance with
Article 250
of the
NEC
or
Section 10/Part One
of the
Canadian Electrical Code
(CEC).
The grounding conductor shall be sized in accordance with
Article 250-122
of the
NEC
or
Part One-
Table 6
of the
CEC
.
— T h e M e t a l O f C o n d u i t I s N o t A n A c c e p t a b l e G r o u n d —
The input, output, and control lines of the system shall be run in separate metal conduits and each shall
have its own ground conductor.
ASDs produce high-frequency noise — steps must be taken during installation to avoid the negative
effects of noise. Listed below are some examples of measures that will help to combat noise problems.
•
DO NOT
install the input power and output power wires in the same duct or in parallel with each
other, and do not bind them together.
•
DO NOT
install the input/output power wires and the wires of the control circuit in the same duct
or in parallel with each other, and
DO NOT
bind them together.
•
Use shielded wires or twisted wires for the control circuits.
•
Ensure that the grounding terminals (G/E) of the ASD are securely connected to ground.
•
Connect a surge suppressor to every electromagnetic contactor and every relay installed near the
ASD.
•
Install noise filters as required.
Grounding Capacitor
The
Grounding Capacitor
plays a role in minimizing the effects of leakage current through the ASD
system and through ground paths to other systems. Leakage current may cause the improper operation
of earth-leakage current breakers, leakage-current relays, ground relays, fire alarms, and other sensors
— and it may cause superimposed noise on CRT screens.
The
Grounding Capacitor Switch
allows the user to quickly change the value of the leakage-reduction
capacitance of the 3-phase input circuit. See figures
4
,
5
,
6
, and
7 on pg. 18
for an electrical depiction of
the leakage-reduction functionality and the methods used to change the capacitance value. The method
used is typeform-specific.
If using a 460-volt ASD that is in the range of 5.0 HP to 25 HP, and the
U/T1
,
V
/
T2
, and
W/T3
connections to the motor are 100 meters or more in length, the ASD
Carrier Frequency
must be set to
4 kHz or less when activating or deactivating the
Grounding Capacitor Switch
. ASD overheating may
occur if the
Carrier Frequency
is set above 4 kHz when activating or deactivating the
Grounding
Capacitor Switch
.
See
pg. 5
for more information on the
Grounding Capacitor Switch
and
pg. 15
for the location.
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