Engineers
SPECIFICATION – RESISTIVE/REACTIVE LOAD BANK
1. Generator Load Bank
Provide a fan-cooled load bank for on-site testing of generators. The intended scope of use shall
be for commissioning standby-power generator plants, periodic testing and exercising of
generators. The load bank shall be designed to operate from a remote control panel as required in
this specification.
Except as otherwise indicated, the load bank and ancillary components shall be of types, sizes,
characteristics, and ratings indicated which, comply with the manufacturer's standard design,
materials, components, and construction, in accordance with published product information and as
required for complete installation.
Manufacturers
Subject to compliance with requirements, the load bank shall be SEPHCO type or approved
equivalent.
2. Load Bank Rating
(a) Load Bank Rating
(b) kW Capacity
(c) kVar Capacity
(d) Power Factor
(e) Control Resolution
(f) Operating Voltage
(g) Frequency
(h) Ambient temperature
(i) Duty Cycle
(j) Cable Connections
: XXXX kVa
: XXXX kW
: XXXX kVar
: 0.8 Adjustable
: XkW (XXXkVa)
: XXXV 3 phase Delta Connected
: 50/60Hz
: 40°C
: Continuous
: PowerLock Connectors
General Description
The load bank shall be fully weatherproof, portable type, incorporating matching resistive and
reactive sections for loading and testing generating systems from 0.8 to 1.0 PF. The load bank
shall be ruggedly built from RHS sections, hot dipped galvanised and enclosed with stainless steel
panels and doors.
The load bank shall have segregated controls for each of the resistive and reactive sections. The
load bank shall be made up of incremental load steps, each step switched by a contactor and
protected by a circuit breaker or DIN type fuses.
Control shall be remote type, supplied with a plug-in 100 metre data cable housed in an extension
reel and an additional 6 meter cable for local operation of the load bank. Control shall be fully
automatic data capture type, designed to operate several load banks when connected together.
CONSTRUCTION
The load bank chassis shall be constructed as a complete frame, from heavy RHS section and a
heavy section channel base with forklift pockets. The chassis frame and housing shall be hot
dipped galvanised prior to assembly of panels and doors. The load bank panels shall be
manufactured from 2mm zinc steel. Doors shall be fitted with pintle style hinges and locks. Gaskets
fitted shall be neoprene type, wire reinforced rubber.
Paint system applied shall be two-pack marine grade acrylic, white gloss automotive finish.
WEATHERPROOFING-SHOCK PROTECTION
The load bank shall be designed for transportability and outdoor use, regardless of weather
conditions. The resistor element materials and type shall be fully sealed for ingress of water or
immersion. The resistor elements shall be fully supported and retained against shock and
vibration. Wire coil type elements and ceramic supports shall not be used. Reactors within the unit
shall be segregated from the resistive section, fixed in place onto heavy channels and fully braced
where necessary.
Air Cooling
The resistor section/s shall incorporate die-cast aluminium impeller/s directly driven by a 900RPM
weather proof motors. Air shall be drawn from the base of the load bank and exit at the top. Air
inlets and discharge shall be fully protected by powder coated screens and louvre grills.
.
Resistor Design and Accessibility.
Resistor elements shall be the Incoloy sheath stainless steel finned type, fully immersion and
vibration proof. Resistor connections shall be fully accessible, terminated in 50kW max size groups
and protected by a circuit breaker. Removal of individual resistors shall be possible without the
need to remove associated parts. Load step increments shall be sized to meet the control
resolution required in the specification
Reactors
Reactors shall be iron cored copper wound class F type, vacuum varnished dipped, designed for
stand-alone operation without the need of forced air-cooling. Load step increments of reactor
sizing shall match the resistive values to provide accurate power factor adjustment required in the
specification. Reactors shall be mounted on steel channels and be fully braced.
Switchgear
Switchgear shall be segregated in two groups, resistive and reactive and arranged in a modular
fashion. Resistor groups shall be switch by contactors, each protected by a re-settable circuit
breaker. The maximum size of the resistor group shall be 50kW. Failure of any component shall be
isolated by its circuit breaker.
Fan Interlocks
Fan interlocks shall guard against loss of airflow, fan reversal, high temperature or fan failure. In
the event of any devise tripping, loads shall immediately shut down and a “Cooling Fault” alarm
status message be displayed on the remote controller. Any fault alarm message shall identify the
load bank in which fault occurs.
Cable Connections
Cable connections shall be provided for external power supply to fan motors and connections to
the main busbars for generator power.
Auxiliary Supply
The control system shall be designed to operate on auxiliary supply as indicated in the
specification in accordance with the manufacturer’s recommendations.
Control Command System
The control system shall be a portable, didicated microprocessor specifically designed for load
bank control. Generic type PLC’s shall not be used. The control shall be capable of carrying out
power measurements, calculations, moniter load bank safety interlock devises and control of
applied loads. As a minimum requirement, the load bank control shall provide means to select the
operating voltage, frequency and power factor ranged from 0.3 to 1.0. Data indication of load
measurements shall as a minimum, be values typically, line to line voltage, phase to phase
voltage, amps per phase, frequency, power factor, target load, actual load and time expired. The
control system shall be able to manage several load banks daisy chained together, and cater for
different load bank sizes.
The data captured and measuring of values shall be by monitoring individual reactive and resistive
groups. Avaraging values by measuring combined groups shall not be acceptable. The system
design to monitor and control shall gurantee high resolution and accuracy of load values, account
for tolerance shift in operating voltage and frequency or variations in the resistor and reactive
components due to temperature fluctuation.
The control unit shall feature operator prompts for ease of operation, provide choice of test type
operation in manual mode or in auotmatic mode.
The unit controller shall be supplied with an appropriate reel and cable for connection to the load
bank’s input socket. Additionally, the controller shall include a USB port for data output to a PC or
Laptop.
Operating Manuals
Three sets of installation/operation manuals shall be provided with the load bank, one manual
retained in a pocket mounted inside the door panel. Each manual shall include installation,
commissioning, operation, maintenace, fault finding, parts identification, circuit and control
diagrams and factory test certificates.