Internal construction and wiring
Eaton regulators are designed such that they can be partially
or completely untanked for inspection and maintenance
without disconnecting any internal electrical or mechanical
connections. External connections must be disconnected.
Regulators equipped with military specification-style,
quick-disconnect circular connector are also equipped with
a solid-state automatic current-transformer shorting device
located in the junction box.
The Quik-Drive tap-changing mechanism is completely fluid-
immersed. The tap-changer, in the manual position, operates
from –16L to +16R in less than 10 seconds.
Refer to
on page 19 for
more information.
The holding switch circuit is an electrical feedback circuit
which monitors motor current. It is incorporated with the
tap-changer motor circuit and control to ensure accurate
indication of tap position and operations counting.
The regulator main coil, reactor, and potential transformer
include thermally upgraded insulation to permit operation up
to 65 °C rise without loss of life to the insulating system. At
65 °C rise, the regulator provides 12% extra current capacity
over the base 55 °C rise current rating.
A patterned, epoxy-coated insulation paper is used in all
windings. Prior to assembly of the main core and coil
assembly, the windings are baked with sufficient mechanical
pressure exerted on the sides of the coil winding to
maximize a complete bonding of the insulation to improve
its short-circuit current withstand capabilities.
The main core and coil assemblies are of the shell-form
configuration. The series winding on the input (source) side
of the regulator (
) allows all windings (control,
shunt and series) to be located in one coil assembly. The
load voltage is monitored by the control winding.
Regulators that have the series winding on the output
) have a separate potential transformer
installed on the load side in lieu of a control winding.
The control winding or separate potential transformer (PT)
supplies a voltage for the tap-changer motor and the control
sensing circuit. Additional taps are available in the PT for line
voltages other than rated voltage.
Most regulators, depending upon the rating, have an
equalizer winding. This winding improves contact life for
high-current applications.
shows a typical regulator power circuit with a
series transformer. This design is utilized when the load
current rating exceeds the tap-changer rating. In this type of
design, the series transformer winding losses are a function
of the load alone and are independent of the tap position.
Because of this, limiting the range of voltage regulation
does not reduce losses and therefore the ADD-AMP feature
is not applicable.
The bridging reactor is a core-form design, consisting of
a coil on each leg of one core. The inside half of one coil
is connected to the outside half of the other coil and vice
versa, providing equal current in each half of the reactor
winding.
This interlacing of the two coils lowers the interwinding
leakage reactance to a very low value. The reactor is
completely isolated from ground by stand-off insulators
since the reactor coil is at line voltage above ground. The
reactor core, core clamps, and other associated parts
approach this level.
The current transformer is a toroid, through which the load
current passes. It furnishes a current proportional to load
current for the line-drop compensator and metering features.
The tap-changer enables the regulator to provide regulation
in smooth, accurately proportioned steps at a controlled
speed that minimizes arcing and extends contact life.
the typical internal wiring schemes. Most of the wiring
is on the tap-changer itself. Molex
®
receptacles plugged
into the junction block inside the junction box on the cover
connect the internal tank wiring to the position indicator
and control. The junction box wiring is shown in
(page 43). The connections are made to the junction box
terminal board using automative-style Molex
®
connectors.
A legacy junction box wiring diagram is shown in
14
VR-32 and EVER-Tap™ Voltage Regulator
InstallatIon, operatIon, and MaIntenance InstructIons
MN225008EN June 2020
