12
SECTION 5
INSTALLATION - PART 2
5.1 GENERAL
The extent of site installation will depend upon the generating set
build, e.g. if the generator is installed in a canopied set with integral
switchboards and circuit breaker, on site installation will be limited
to connecting up the site load to the generating set output
terminals. In this case reference should be made to the generating
set manufacturer's instruction book and any pertinent local
regulations.
If the generator has been installed on a set without switchboard or
circuit breaker the following points relating to connecting up the
generator should be noted.
5.2 GLANDING
The standard build terminal box arrangement is for cable entry into
the right hand side of the terminal box when viewed from generator
N.D.E. with removable panel for easy adaptation to suit specific
glanding requirements.
Incoming cables should be supported from either below or above
the box level and at a sufficient distance from the centre line of the
generating set so as to avoid a tight radius at the point of entry into
the terminal box panel, and allow movement of the generator set
on its anti-vibration mountings without excessive stress on the
cable.
In addition the cable should be clamped at the gland so that forces
on the cable due to set movement cannot be transmitted to the
insulated terminals in the terminal box.
Before making final connections, test the insulation resistance of
the windings. The AVR should be disconnected during this test and
RTD leads grounded.
For the MAIN STATOR WINDINGS the following type of megger or
similar instrument should be used.
LV Generators: 500V Motorised Instrument.
MV Generators: 2500V Motorised Instrument.
HV Generators: 5000V Motorised Instrument.
The measured Insulation Resistance should be above the value
stated in the table below.
GENERATOR TYPE
LV
MV
HV
5 Meg Ohms
50 Meg Ohms
200 Meg Ohms
If these values cannot be achieved the windings should be dried
out as detailed in the Service and Maintenance Section of this
manual.
A 1000V instrument is suitable for all other windings and a
minimum insulation resistance value of 1Meg Ohms should be
recorded.
5.2.1. CONNECTIONS ON MV & HV
GENERATORS
When making connections to the insulated terminals
the incoming cable termination should be placed on top
of the winding lead termination(s) and clamped
between the two nuts provided as shown in Fig. 5
Fig. 5
Caution!
The load cables must not be
connected via any rigid right-angled
extension bar to the main terminals.
This will cause excessive side
loads on the ceramic insulations.
Important !
To avoid the possibility of swarf
entering any electrical components
in the terminal box, panels must be
removed for drilling.
5.3 EARTHING
The neutral of the generator is not bonded to the
generator frame as supplied from the factory. An earth
terminal is provided inside the terminal box adjacent to
the main terminals. Should it be required to operate
with the neutral earthed a substantial earth conductor
(normally equivalent to one half of the section of the
line conductors) must be connected between the
neutral and the earth terminal inside the terminal box.
The generator feet should be already bonded to the
generating set bedplate by the generating set builder,
and will normally be required to be connected to the
site earth system.
Caution!
Reference to local electricity
regulations or safety rules should
be made to ensure correct
earthing procedures have been
followed.
