As an emergency backup
power source, diesel generator sets are increasingly accepted and used by many
industries due to its reliability, timeliness and safety. However, purchasing a
suitable diesel generator set is not an easy task.
If you decide to buy a emergency diesel generator, you are advised to read the below instructions before placing
an order.
1.
Common Enquiry
A. Power supply
parameters: output voltage 230V/400V, frequency 50HZ, genset speed 1500r/min.
B. Automatic display and
recording of operating data: including water temperature, oil pressure, speed
and running hours.
C. Protection device:
diesel engine overspeed, start or stop failure, low oil pressure, high oil
temperature, excessive cooling water temperature, generator overload, short
circuit, loss of pressure and failure of the vehicle, etc, the genset will give
alarm according to different conditions (including lighting, audible alarm),
open and even stop automatically.
D. It should be equipped
with 24V DC starter motor and battery as electric starting system battery power
is monitored by computer control.
2.
Capacity
A. The rated operating
power of the generator set is not less than the rated power of the stable load.
B. The standby operation
power of the generator set is not less than the peak power of the load.
C. When the maximum
motor starts, the instantaneous voltage drop of the generator is no more than
15%-20%.
3.
Selections of Starting Method
There are three ways to
start a diesel engine: manual start, electric start and compressed air start.
Among them, the electric starting is to use the electric motor as the power to
drive the crankshaft to rotate through the transmission mechanism, so that the
diesel engine is started, the power supply battery used by the electric motor,
and the starting mode should be adopted in the high rise building. At the same
time, the selected genset should be equipped with fast automatic start and
automatic power switch device to ensure power supply within 15s after the power
supply of the city network is interrupted.
4.
Speed
The diesel engine used
for power generation has an adjustment diesel engine with a speed of not less
than 1000r/min, the medium speed diesel engine has two speeds of 750r/min and
600r/min. In the high rise building, an adjustment unit with a rotational speed
of 1500r/min should be used. This unit has a large volume per unit volume, so
the volume is small and the weight is light, which can save floor space. The
disadvantages of large running parts and short life spans are not considered
for emergency genset with short running times.
5.
Does The Generator Set Have a Supercharger?
When the generator set
is equipped with a supercharger, the air required for combustion is
supercharged by the supercharger and sent to the diesel engine, so that the
density of the intake air is greatly increased. The same cylinder volume can
burn more fuel, and the same type of non-supercharging. After the diesel engine
is boosted, its output power can be increased by 50%. the turbocharger of the
general diesel engine is an exhaust gas turbocharger, and the exhaust gas
discharged from the diesel engine drives its work. The main disadvantage of the
supercharged diesel engine is that the supercharger has a high rotational
speed, short life span, and is prone to failure. But currently, the new machine
has solved these problem and make it better.
6.
Excitation Mode Selection
There are many kinds of
excitation devices, such as a generator with a DC exciter, a self-excited
constant voltage generator without a DC exciter, and a brushless excitation
generator. The brushless excitation generator is a new type of generator
developed in recent years. This kind of generator completely eliminates various
carbon brushes and it reliable in operation. When used with the automatic voltage
regulating device, the static voltage adjustment rate error can be guaranteed
within 2.5%. This type of machine can adapt to various operating modes, and it
is easy to realize automatic or remote control of the genset.
7.
Selection of Cooling Method
There are two types of
cooling methods for diesel engines: water cooling and air cooling. The complete
unit of closed water circulation cooling is widely used in high-rise buildings
due to its small footprint.
8.
Selection of Genset Automatic Power
As a diesel standby generator, the genset can quickly supply power to the emergency load when
the external power supply fails. Therefore, the generator set should have the
single-machine automation functions such as emergency self-start, automatic
shutdown, automatic fault protection and recording mentioned above. For the
specific situation, the following automation functions are selected.
A. Automatic grading
loading: Some units are not allowed to suddenly increase the full load, and
also prevent the inductive load from starting at the same time. Automatic
grading loading can be set.
B. Automatic parallel:
When the unit is automatically connected, the automatic parallel system can be
set to automatically parallel the vehicle in the same way.
C. Automatic frequency
modulation and load regulation: When the machine is running in parallel, the
unit throttle is automatically adjusted to keep the power supply frequency and
the load of each unit within the allowable deviation range.
D. Remote control of the
unit: The genset needs to have RS232 standard interface and communication
protocol, in line with the world-wide Lonworks technical standards.
E. Automatically
maintain the starting state: The auxiliary system of the generator's starting,
lubrication, fuel and cooling should be automatically kept ready to start,
including automatic charging, automatic heating of lubricating oil and cooling
water.
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