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Section 1
General Information
3-6 Receiving & Installation MN722
Figure 3-2 Recommended System Grounding – EK
L1
AC Main
Supply
Safety
Ground
Driven Earth
Ground Rod
(Plant Ground)
Four Wire
“Wye”
L1
L2
L3
Earth
LOCAL
SHIFT
DISP
RESET
PROG
ENTER
JOG
STOP
REV
FWD
L2 L3 T1 T2 T3
Series H
Boost
Regulator
Optional
Load
Reactor
Route all 4 wires L1, L2, L3 and Earth
(Ground) together in conduit or cable.
Route all 4 wires T1, T2, T3 and Motor
Ground together in conduit or cable.
Connect all wires (including motor ground)
inside the motor terminal box.
Ground per NEC and
Local codes.
Line
Reactor
Note: Wiring shown for clarity of grounding
method only. Not representative of
actual terminal block location.
Note: A line reactor is required and
must be ordered separately.
Note: A load reactor is highly recommended
and must be ordered separately.
Note: A boost regulator is required and
provided with each model EK control.
Ungrounded Distribution System
With an ungrounded power distribution system it is possible to have a continuous current
path to ground through the MOV devices. To avoid equipment damage, an Isolation
transformer with a grounded secondary is recommended. This provides three phase AC
power that is symmetrical with respect ground.
Input Power Conditioning
Baldor controls are designed for direct connection to standard three phase lines that are
electrically symmetrical with respect to ground. Certain power line conditions must be
avoided. An AC line reactor or an isolation transformer may be required for some power
conditions.
S Baldor Series H controls require a minimum line impedance of 3%. Refer to
“Line Impedance” for additional information.
S If the feeder or branch circuit that provides power to the control has
permanently connected power factor correction capacitors, an input AC line
reactor or an isolation transformer must be connected between the power factor
correction capacitors and the control.
S If the feeder or branch circuit that provides power to the control has power
factor correction capacitors that are switched on line and off line, the capacitors
must not be switched while the control is connected to the AC power line. If the
capacitors are switched on line while the control is still connected to the AC
power line, additional protection is required. TVSS (Transient Voltage Surge
Suppressor) of the proper rating must be installed between the AC line reactor
or an isolation transformer and the AC input to the control.