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TRANSFORMER RECTIFIERS
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The key to
any impressed current system is an efficient and reliable power unit
that can provide an uninterrupted direct power supply to the anode
installation (s). ETC-CPS can offer a fully comprehensive range of
transformer- rectifiers, designed for a minimum life of 25 years in the
following options:
Current output up to several thousands of amps can be supplied.
Experienced cathodic protection engineers are available to advise as to
the most efficient and economical transformer-rectifier units for any
given application.
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General
Characteristics
Input
AC supply as determined by site conditions, for
example:- 220-240 volts, single phase, 50/60 Hz 03 380-440 volts, three
phase,
50/60 Hz
Output and Control
DC output will be sized to suit the
requirements of the structure(s) being protected. The most
economical method of control usually depends upon the size of the unit,
typically:-
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Low
Power Units, 0-50 amps: Stepless variac type regulator.
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Medium to High Power Units 25-1000 amps:
On-load transformer tapping switches, to give 63 equal steps or using thyristers, control by continuously variable lockable potentiometer
0-100%. (The latter
can also give constant current characteristics).
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Automatic Units: Thyrister controlled output variation by continuously
variable lockable potentiometer 0-100%.
Rating-Continuous
Climatic Conditions
Generally suitable for temperatures up to 50° C
at 100% relative humidity. Higher ambient ratings can be provided
upon request
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Oil cooled units
These types of units are preferred for outdoor locations except where
the output is low. All units are supplied with a first filling of
oil to BS 148. Oil cooling allows a smaller cubicle to be used
whilst maintaining a high degree of protection from ingress of moisture
or dust. The silicon diode rectifiers, transformer and shunts are
housed below the oil. The DC terminals, AC input terminals and
circuit breakers, fuses, controls, meters, and any printed circuit
boards are located in a dry compartment generally on the side of the
main unit.
The
following are standard fittings:
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Separate DC output voltmeter and ammeter
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Oil sight gauge
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Oil filter and drain plug
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Silica gel breather
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Thermometer pocket oil temperature indicator
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Weatherproof cubicle to IP65, plinth mounted unless otherwise specified.
2 - 3.5 mm steel thickness
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Air cooled units
These units are normally for indoor applications (or outdoors when the
output is low). The enclosure is either ventilated or totally
enclosed to IP55. All components are easily accessible but
protected from accidental contact by means of a removable panel.
Cabinets are fabricated from 2 - 3 mm thick sheet steel suitable for
floor, pole or wall mounting and can be designed to share space within
an existing control room.
Equipment for
Hazardous Areas
Units for use in hazardous areas where flammable concentrations of gases
or vapours could be present, require special equipment. ETC-CPS
can supply equipment in compliance with most International safety codes
and practices such as BS 5345 and NEC Article 501 through 503. To
specify the equipment for hazardous areas, the following information is
necessary:
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Classification
of hazardous location e.g. European terminology (Zone 1) or North
American terminology (Class 1 Div 2)
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Class
of vapours and gases present, e.g. BS 4683 Group 11B or Ethyl- ether
ethylene NEC
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Group
C
Cubic Coatings
Coatings of cubicles can be to customer specification. Typical
specification:
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Indoor units - blast clean to SAE 2½, primed, coated with two coats
of semi gloss paint.
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Outdoor units - blast clean to SAE 2½, zinc rich primer, undercoat
and finish with stoving enamel topcoat.
Optional Extras
Units can be fitted with additional items at the Customers request.
These would typically be:
Switch Mode
Rectifier
ETC-CPS can offer a fully comprehensive range of switch mode rectifiers.
These rectifiers are designed with solid-state circuitry for trouble
free performance. All modules can operate in three different
modes, constant current, constant voltage and potential control.
These rectifiers can
be provided with a programmable timer to enable collection of
instantaneous OFF potentials. (IR error free potentials) by utilizing
standard data loggers or using a normal PC by connecting to the RS 232
port. The rectifier modules offered can operate both local and remotely
via cable, modem or Internet.
Each unit can
incorporate the following equipment:-
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Combined digital
display showing amp, volt and potential.
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Panel light
indicating power on
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Data logger for
collection of data via a laptop or via remote operation.
Features
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High accuracy and
very low ripple
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Ease of interface
with computers
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Wide range of options
to suit your process
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Available in module
version without casing for assembling into cubicles
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Designed according to
International standards
Advantages
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