Connecting power to external source terminals
120 Vac applications to an Eaton's Cooper Power series 120 V control
Option 1:
The control box assembly is connected to earth ground
to provide protection to operations personnel. This is a
typical field application where the control is mounted on a
grounded regulator tank or dropped down a pole with the
control box grounded properly.
Since the control is configured for 120 Vac, a 1:1 isolation
transformer must be used to isolate the supply voltage.
This isolation transformer must isolate both the neutral and
line on the secondary side. Also, the neutral and ground
on the secondary side should not be bonded or connected.
To check isolation from earth ground, check the continuity
of each lead on the isolation transformer with respect to
ground (G). Check this before connecting the leads to the
control panel. See
The control panel assembly is grounded through the tank
or a separate grounding strap. Earth ground of the isolation
transformer is not connected to the control. The only source
of earth ground reference on secondary of the isolation
transformer is through the control box connection to
ground.
Option 2:
The control box assembly is floating. This is a typical shop
or lab application where the control is mounted on an
ungrounded regulator tank or sitting on a workbench.
The 120 Vac external source must be completely isolated.
In most cases an isolation transformer is needed. This
isolation transformer must isolate both the neutral and line
on the secondary side. Also, the neutral and ground on
the secondary side should not be bonded or connected.
To check isolation from earth ground, check the continuity
of each lead on the isolation transformer with respect to
ground (G). Check this before connecting the leads to the
control panel. See
In this case, the ground of the isolation transformer is
connected to the green terminal post on the CL-7 control.
In this configuration, the only source of earth ground
reference on the secondary side of the isolation transformer
is through the control box connection to the isolation
transformer ground.
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INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS
MN225003EN April 2018
CL-7 Voltage Regulator Control