The generators have been designed for use in a maximum ambient temperature of 40°C, and
altitude less than 1000 metres above sea level in accordance with Bs5000. Ambient in excess
of 40°C, and altitudes above 1000 metres can be tolerated with reduced ratings-refer to the
factory.
The generators are of air-ventilated scteen protected dripproof design and are not suitable for
mounting outdoors unless adequately protected by the use of canopies. Anticondensation
heaters are recommended during storage and for standby duty to ensure winding insulation is
maintained in good condition.
When installed in a closed canopy it must be ensured that the ambient temperature of the
cooling air to the generator does not exceed that for which the generator has been rated. The
canopy should be designed such that the engine air intake to the canopy is separated form the
generator intake, particularly where the radiator cooling fan is required to draw air into the
canopy. In addition the generator air intake to the canopy should be designed such that the
ingress of moisture is prohibited. Preferably by use of a two stage lter.
The air intake/outlet must be suitable for the air ow given in the following table with additional
pressure drops less than or equal to those given in table 1 below:
The generators may be tted with air f ilters. These are oil charged wire gauze lters and require
charging during installation.
IMPORTANT! Reduction in cooling airow or inadequate protection to the generator can
result in damage and/or failure of windings
Dynamic balancing of the generator rotor assembly has been carried out during manufacture in
accordance with BS 6861 Part 1 Grade 2.5 to ensure vibration limits of the generator are
in accordance with BS 4999 Part 142.
The main vibration frequencies produced by the component generator are as follows:
The standard terminal box is arranged for cable entry on the right hand side looking from the
end of generator. If specied at the time of order cable entry may be arranged on the opposite
side.
The terminal box is constructed with removable panels for easy adaptation to suit specic
glanding requirements. With in the terminal box there are insulated terminals for line and
neutral connections and provision for earthing. Additional earthing points are provided on the
generator feet.
The neutral, as supplied from the factory, is NOT connected to the frame.
Warning! No earth connections are made on the generator and reference to site regulations
for earthing must be made. In correc tearthing or protection arrangements can
result in personal injury or death.
Fault current curves (decrement curves), together with generator reactance data, are available
on request to assist the system designer to select circuit breakers. Calculate fault currents and
ensure discrimination within the load network
4.1 VIBRATION
Vibrations generated by the engine are complex and contain harmonics of 1.5,3,5 or more
times the fundamental frequency of vibration. The generator will be subjected to this vibration,
Which will result in the generator being subjected to vibration levels higher than those derived
from the generator itself.
The generators are designed to withstand the vibration levels encountered on generating sets
built to meet the requirements of ISO 8525-9 and BS5000-3. (Where ISO 8525 is taken to be
broad band measurements and Bs 5000 refers to the predominant frequency of any vibrations
on the generating set.)
Denition of BS 5000-3
Generators shall be capable of continuously with standing linear vibration levels with amplitu-
des of 0.25 mm between 5 Hz and 8Hz and velocities of 9.0mm/s rms between 8 Hz and 200
Hz when measured at any point directly on the carcass or main frame of the machine. These
limits refer only to the predominant frequency of vibration of any complex waveform.
Denition of ISO 8528-9
ISO 8528-9 refers to a broad band of frequencies, the broad band is taken to be between 2
Hertz and 300 Hertz. The table below is an example from ISO 8528-9 (value 1 ). This simplied
table lists the vibration limits by KVA range and speed for acceptable genset operation.
It is the responsibility of the generating set designer to ensure the alignment of the gen set,
stiffness of the bed-frame and mountings are such that the Vibration limits as dened above
are met.
If the Vibration levels of the generating set are not within the parameters quoted above:
1. Consult the genset builder. The genset builder should address the genset design to reduce
the vibration levels as much as possibie.
2. Discuss, with
3. The impact of not meeting the above levels on both bearing and generator life expectancy.
IMPORTANT! Important, refers to hazard or unsafe method or practice which can result
in product damage or related equipment damage. Exceeding either of the
above specications will have a detrimental effect on the generating bea
rings.
IMPORTANT! (See section on bearings). This will invalidate the generator warranty. If you
are in any doubt, contact newage International Linmted
In standby applications where the running time is limited and reduced life expectancy is accep-
ted, higher levels than specied. in BS5000 can be tolerated, up to a maximum of 18mm/sec.
Two bearing generators require a substantial bedplate with Engine/generator mounting pads to
ensure a good base for accurate alignment. Close Coupling of engine to generator can increa-
se the overall rig idity of the set. A exible coupling designed to Suit the Specic engine/gene-
rator combination, is recommended to minimise torsional effects.
Alignment of single bearing generators is critical and vibration can occur due to the exing of
the anges between the engine and generator. A substantial bedplate with engine/generator
mounting pads is required.
The maximum bending moment of the engine ange must be checked with the engine manu-
facturer.
Torsional vibrations occur in all engine-driven shaft systems and may be of a magnitude to
cause damage at cerrain critical speeds. It is therefore necessary to consider the torsional
vibration effect on the generator shaft and couplings.
It is the responsibility of the generator set manufacturer to ensure compatibility, and for this
purpose drawings showing the shaft dimensions and rotor inertia are available for customers to
forward to the enginesupplier. In the case of single bearing generator coupling details are
included.
IMPORTANT! Torsional incompatibility and/or excessive vibration levels can cause
damage or failure of generator and/or engine components
57
To Next Page
Loading...
