The following factors must be considered before commencing the installation
•level, weight load and vibration transmission characters of the foundation
•sufficient cooling air
•sufficient fresh air intake
•cooling air exhaust
•engine emission exhaust
•operation and maintenance space
Generator set Location
The Generator set is located in relativity to the position of other systems such as ventilation duct,exhaust duct, wiring, fuel pipes, etc.. The Generator set shall be as nearer to the main power switchgear as possible.
Generator set be attached to the concrete floor
1. If the Generator set is to be attached to the concrete floor, a concrete block must be built on the floor on which the Generator set will be installed.
2. The concrete block shall be a steel-reinforced concrete structure which can withstand a pressure test that lasts 28 days with a pressure strength of above 2,500 psi (173kpa) . The block rises at least 6 inches (150 mm) above the floor and extends for at least 6 inches (150mm) from every side of the Generator set base frame.
“J” or “L” bolts must be preinstalled to the block to anchor the Generator set or vibration isolating pads.
Generator set be attached to the vibration isolation foundation (VIF)
If the environment is extremely sensitive to vibration or noise, the Generator set shall be fixed to a VIF to diminish vibrating impact on the building. The dynamic weight load capacity of the VIF needs to be at least twice the weight of the Generator set (fuel weight in the tank may be excludedfrom the Generator set weight). The following figure shows a typical VIF. The parameters are as the following:
1. The VIF shall be at least 150 to300mmlonger and wider than the Generator set base frame,hence the length (L) and breadth (B) of the VIF is decided.
2. The VIF rises 20 to300mmabove the floor
The depth of the foundation is decided by the following formula: H＝K×G /d×（B＋0.4）×（L＋0.4）
d －cement density，normally145lbs/ft³(2400 kg/m³) K－ times of the Generator set weight, normally 2；
G－gross Generator set weight，kg； B－breadth of the foundation，m；L－length of the foundation，m。 E.g. Generator set AP900: length4.3m，breadth1.8m，gross weight5800kg; Foundation depth H ＝( 2.0x 5800) / ( 2400 x 4.7 x 2.2 ) ＝0.467m
1. Certain space must be reserved along the rim of the foundation to allow for expansion at low temperature.
2. The reinforced concrete used for the foundation must withstand a 28-day pressure test at above 2,500 psi(173kpa).
3. The intensity of pressure on the floor from the total weight of the Generator set, fuel and VIF shall be lower than 96kpa.
4. Generator set base and vibration isolation pads are anchored to the VIF with “J” or “L”bolts.
5. When the Generator set is mounted to the floor, it shall be ensured that the floor can carry 1.5 times the Generator set wet weight to accommodate static and dynamic loads .Vibration dampers must be inserted between the Generator set base and the floor.
Note: All foundations must be solid and smooth enough. For concrete structures, no further treatment is needed as they usually satisfy the physical requirement.
Generator set Fixation and Vibration Isolation
1. Some SOMAX Generator sets are equipped with built-in anti-vibration mechanism that consists of rubber vibration isolators inserted between the Generator set body and the steel base frame. Therefore, unless in extremely sensitive environment where extra vibration isolators are needed between the steel base and the installation foundation, the steel base can be directly fixed onto the surface of the installation foundation.
2. For Generator sets without built-in anti-vibration mechanism, vibration isolators must be used between the steel base frame and the installation foundation.
3. Vibration isolators can reduce the noises and vibration transmitted to the foundation. Several kinds of vibration isolators are used of which the spring isolator is 98% efficient, fiberglass isolator is 75-85% efficient, and rubber isolator is 50-80% efficient. In places where the nvironment or geology pose a stricter requirement on anti-vibration performance, 25-30mm wide ditches must be dug around the installation foundation and an extra vibration damping layer be added to the bottom of the foundation. The damping layer is a200mmthick mixture of cement, cinder and bitumen, sitting on a firm surface. The body of the installation foundation is built on top of the damping layer.
4. The Generator set steel base frame must be fixed to the ground with M18 bolts to prevent displacement.
There must be enough space around the Generator set to allow maintenance operations. Each side of the Generator set, except where the radiator is located, shall be at least1.5maway from the wall. The height of the Generator set room is usually over 4.5m with the ceiling being 1.5m or further away from the Generator set top. This is the minimum spacial requirement considering hoisting actions and ventilation. The base shall be at least150mmabove the floor.
Mechanical Connection of the Generator set
The exhaust system is supposed to discharge waist gases into the atmosphere and keep it away, together with dust and noise, from the buildings and human crowds. For Generator set, in order to achieve rated power output, backpressure in the exhaust system must be onsidered carefully. Requirements for the exhaust system include the following:
1. The exhaust backpressure of the whole exhaust system does not exceed the maximum value as described in the parameters list for the diesel engine.
2. Components of the exhaust system shall not exert too much stress on the exhaust manifold or urbocharger due to gravity, inertia, relative motion between components and thermal expansion.
3. The exhaust system shall be able to prevent ground spills, rainwater, flush water and other sources of liquids from entering the diesel engine or turbocharger.
4. Ensure that the diesel emission do not impair the function of the air filter and cooling system nor exert any harm on the surroundings and operation staff.
Layout and Installation of Exhaust Piping
a) Corrugated stainless steel pipes must be used to link the engine exhaust outlet to the exhaust pipe or as
elbow where the pipe makes a turn. The pipes are mounted on incombustible flexible suspension hanging from the ceiling or supported by ground flexible frame to absorb thermal expansion, Generator set movement and vibration.
b) For multiple Generator sets, each Generator set must have its own exhaust system with the outlets being exposed to the atmosphere. No check valves are allowed.
c) Make the piping as short and horizontal as possible with a minimum total length and number of bends. Each section of pipe should not be too long or bend too sharply. There should be no more than 3 elbows in the bend radius of which is at least three times the pipe diameter.
Requirements on pipe size:
1. For the first 9m of pipes connected to the engine exhaust outlet, the pipe inner diameter shall be the same as the engine exhaust outlet; for the next 6m of pipes, the inner diameter shall increase by 2.54cm. Followingly, for every9mof pipes, the diameter increases by 2.54cm until a maximum pipe length of 27m. The equivalent length of elbows is calculated in the following way: One 90° elbow=(2.5-3)times the outer diameter of the pipe.
2. For horizontal pipes, the slant grade shall be 0.3-0.5%, leading outside the building with the low end placed remotely from the engine. A deposit drain is to be used at the lowest point and a condensation drain be used directly under vertical pipes.
3. Protections must be used at the outlet of the exhaust system to repel rainwater. For outlet that is routed straight upwards, automatic rain caps shall be used.
4. When the exhaust pipes piece through flammable roofs, walls or other partitions, insulation sleeve and wall seals must be used for heat insulation. The inner diameter of the sleeve shall be 25mm larger than the outer diameter of the exhaust pipe and insulation materials are to be inserted in between.
5. Try to locate most of the exhaust pipes outside the Generator set room to reduce heat radiation.Exhaust pipes inside the room shall be insulated with 50mm thick high density insulation materials protected by aluminum panels. The minimum space between the exhaust pipes and flammable materials is300mm.
6. The exhaust system shall be placed in a high leeward position.
The fuel system is to provide adequate good quality diesel to the diesel engine. The diesel must be clean,less than 60 ℃, containing no water, corrosive liquids and paraffin wax, without too much air and with enough heat value. Before being drawn into the day tank, the diesel must be pretreated with 48 hours of sedimentation. Diesel stored in the standby fuel tank shall be refreshed within 18 hours or proper amount of anti-corrosion agent must be added. Since the anti-corrosion agent can reduce fuel economy and the Generator set starting performance, we recommend not using it.
a) The fuel tank must be big enough to allow the Generator set to run at full load for rated hours plus 5% room for thermal expansion.
b) For simple installation, the fuel tank must be placed in such a position so that the highest level of the fuel is not more than2.5mhigher then the Generator set base frame, or a bobber tank/auxiliary tank must be used.
c) The fuel tank must be clean with no rust or corrosion. It is usually made of terne plate,parkerized plate, reinforced plastic or aluminum sheet. Galvanized sheet is not allowed as it scales in contact with the fuel and causes clogging in the fuel filter and injector.
d) The fuel intake of the fuel pump shall be placed in the center of the tank,25mm above the bottom. This will make the pumping easier and avoid sucking up water and impurities.
e) The inlet of the fuel pump shall always be positive static head. The fuel tank outlet shall be at least 0.5m higher than the Generator set base level. However the fuel tank shall not be too high so as to exert a higher pressure on the inlet of the fuel pump than the fuel pump can withstand. In applications that pose strict requirement on the starting performance of the Generator set, e.g. the Generator sets work in parallel or quick starting is required in emergencies, the fuel tank/storage shall be placed in such a position so that the lowest level of the fuel is150mmhigher than the pump inlet. This will prevent accumulation of air in the fuel pipe when the Generator set is on load.
f) The fuel returnduct connections must not be positioned too high as to exceed the sucking capacity of the fuel pump. Normally the height is below2.5m.
a) Fuel pipes connected to the engine shall be made of flexible hose to absorb Generator set displacement and vibration.
b) Diesel must be carried in black mild steel pipe. Cast iron or aluminum pipe is prohibited since they have a relatively loose structure and have a risk of fuel leakage.
c) Do not use galvanized sheet to make the fuel pipe, joints and tank. The sulfur in the fuel will combine with the condensation liquid in the tank to form sulfuric acid, corroding the galvanized layer and causing clog in the fuel pump and filter.
d) Appropriate fuel pipe size shall be selected to keep the flow resistance within a reasonable range. The pipe size shall be at least the same as the inner diameter of the fuel pump inlet. If the fuel tank is far from the engine, the pipe size shall increase and try to use as less elbows and joints as possible.
e) Whether the engine is running or standing by, leak, even the slightest, shall be avoided of the fuel system. Air may enter the fuel through the leak and cause instability of the engine and lower the power output.
f) During the installation of the fuel system, be every cautious of moisture and pollutants such as dust. Clean every component of the fuel system before installation.
Cooling and Ventilation System
Cooling and ventilation system is extremely important for the Generator set room. There must be enough air flowing through the Generator set room to supply engine combustion and cooling.To allow the engine to work at
its best, the temperature rise in the room shall be between 10-150℃ with the ambient temperature in the room
being no higher than 400℃. If the ambient temperature is above 400℃, the air must be taken in from the atmosphere via duct.
There are four types of cooling system
a) engine mounted(standard) radiator
b) remote mounted radiator
c) engine mounted heat exchanger cooling system
Engine mounted (standard) radiator
SOMAX Generator set set is usually provided with an engine mounted radiator. The Generator set must be placed in a room with good ventilation where the fan draws in the air across the radiator and discharge it outdoors through the exhaust pipe connected to the radiator.
Arrangements in this system are as the following:
a) In rooms where the air is sufficient, the hot air exhaust shall have a ventilation area 1.25 to 1.5 times that of the radiator. If metal louver or grid is installed on the outlet, please ensure the ventilation area is sufficient.
b) When installing the Generator set, try to locate the radiator as close to the hot air exhaust as possible so that hot air will not be circulated in the room. If no wind duct is used, we recommend that the distance between the radiator and hot air exhaust does not exceed150mmor canvas/thin-walled wind duct shall be applied and the distance between the radiator exhaust surface and air barrier be at least 2m. If the distance is too short, exhausted hot air will be reflected by the barrier to heat the water tank, resulting in increased temperature of coolant.
c) The wind duct inside must be smooth and free from obstacles, leaks, holes and sharp bends. The change of duct section dimension shall be gradual, sometimes with the help of diversion plates to reduce pressure loss. If the air flow pressure difference is too great and can’t be altered, electric blower shall be used to enforce air flow.
d) Air inlet shall allow the air to flow across the Generator set. It shall be located lower than the air exhaust to facilitate air convection and help suck the air into the room.
e) Fresh air temperature around the radiator shall not exceed the rated environment temperature for the chosen radiator type (400℃ or 500℃). If the temperature is too high, measures must be taken to cool down the Generator set room.
f) The system must be able to prevent rain and snow from infiltrating. In cold regions, heat preservation must be applied to rooms where standby Generator sets or seldom-operated Generator sets are located. The preservation method may be the use of air damper.
g) In cold regions, the coolant for Generator set automatically run upon fault of the main power supply shall be treated to increase anti-freeze ability. The coolant may be an even mixture of cooling water and 40-60% ethylene glycol. Meanwhile, submerged thermostat-controlled coolant heaters (supplied by utility power) shall also be used. When the Generator set is standing by, the heater shall be able to sense the environment and coolant temperature and heat the coolant automatically to maintain the coolant temperature between 50℃ to 400℃.
h) The cooling system must be equipped with an anti-corrosion water treatment device (water filter). The water filter contains anti-corrosion additives which help maintain certain level of chemical intensity in the coolant to protect it from corrosion. The water filter will also clean the coolant by stopping and depositing impurities during the continuous circulation of the coolant. However, a thorough cleaning for the whole system is still required within every 30 days/250 hours.
Remote Mounted Radiator
When good ventilation is not available in the Generator set room, a remote mounted radiator system can be used. However, considerations must be given on anti-freezing of the ductwork and the surplus of fresh air to carry out the heat and support engine combustion.
1. The coolant flow resistance outside the engine (including piping, equipment and radiator friction pressure loss) and the static head (the high of the liquid based on the central line of the crank) shall not exceed the stated value in the engine handbook.
2. Excessive static head (water pressure) would damage the seal of the coolant pump; excessive flow resistance (pressure loss) would result in overheating of the engine. If the coolant friction is greater than
the rated value, a backup water tank and a electric water pump are required. The backup water tank should have a capacity equal to over 15% of the system coolant amount; if the remote radiator is3mor more higher than the Generator set crank central line, an auxiliary tank or depressurizing valve shall be used to avoid damage to the coolant pump seal.
Engine Mounted Heat Exchanger
The engine, circulation pump, heat exchanger and cooling tower/pond comprise a closed pressure circulation cooling system. Engine coolant and raw water are in separated pipes. This type cooling system requires less space than remote mounted type and considerations must still be given on ductwork anti-freezing and air supply for
a) There must be enough raw water to absorb the heat from the coolant. The temperature of the raw water after heat exchange should not be over600℃.
b) Full consideration must be given to the water pressure on the water inlet of the heat exchanger. If the pressure is higher than the designed pressure bearing capacity of the heat exchanger, depressurizing valve or tank must be used.
c) A cooling system with the combination of cooling tower and heat exchanger can avoid problems such as water pollution and freezing.
d) When designing the coolant circulation system, customers must consider the necessity of installing filtering devices such as filter or filter mesh. The turbidity of the circular water shall not be more than 50mg/L. No oil contaminant and impurities are allowed. A thorough cleaning of the whole system must be conducted within every 30 days or 250 hours.
e) The hot water circulation pump shall coordinate with the cooling tower in terms of working ability. The rated flux carried by the pump shall be close to the handling capacity of the cooling tower and the rated pumping pressure shall meet the nominal pressure at the water intake of the cooling tower. If the height difference between the cooling tower water intake and the engine water drainage pump is between 2.5m to 3.5m(for specific parameters, please refer to the technical handbook of the engines), circulation pump may not be necessary. In this case,connect the water outlet of the engine Generator set Electric Connection After finishing mechanic connections, customers may start electric connection according to the drawings we provide. Generator set electric connection includes load connection, control circuit connection and battery connection.
Only qualified electricians are allowed to conduct connection work and they must be tested and verified before starting. All connections, cape sizing and layout must comply with relevant electric codes.
Alternate Current Circuit
The Generator set and the load shall have corresponding phases no matter what kind of connection forms are used, triangle or star formats.
When the Generator set is connected to the load, please balance the load so that the same amount of current passes through each connection terminal. If the Generator set is connected to a single phase load and a three-phase load simultaneously, particular attention must be given to load balance. If the current in every phase is approximately the same (within 10% difference)and the current on the line does not exceed the rated value,the Generator set can be connected to any combination of single phase and three-phase loads. During operation, please check the amperometer on the control panel to keep watch on the current through each terminal.
Grounding means connecting the metal components of the Generator set and/or the Generator set circuit to the ground. The design and installation of the grounding system are subject to many factors such as requirements on grounding fault protection for compound transformer and the actual location of the Generator set. When installing the grounding system, please consult qualified electric engineer. Normally, the internal combustion Generator set designing codes require that TN-S system is used with three phase four cords cable and direct neutral point grounding. The neutral N wire is separated from the protective PE wire everywhere in the system. They work with the gradual creepage protection phase to ensure safe use of the electricity. However, when using this system, attentions must be paid to the following:
a) The protective zero line shall never be disconnected.
b) Equipment within the same electric circuit are not allowed to be protected for some part by grounding and for some part by zero.
c) Expected specifications of the PE wire:
d) The section of the PE wire shall be no smaller than that of the working zero line and use bicolor wires of Yellow/Green. PE wire connected to electric equipment shall be insulated multi-cord copper wire with a section of at least2.5mm2. The zero line shall be connected securely to electric equipment using bronze joint pins. Hinge connection is not allowed. The connecting terminal of electric equipment shall be galvanized or treated with anti-corrosion oil. The zero line shall be
>100KVA low voltage Generator set R<4 ohm
< 100KVA low voltage Generator set R<10 ohm
Electric protective grounding R<4 ohm
Zero line regrounding R<4 ohm
Grounding short circuit Id>4000AR<2000/Id
Grounding short circuit Id<500A 10 ohm>R<120/Id
Direct Current Circuit
Direct Current Circuit Connections
Control wires must be laid in a conduit isolated from alternate current cables or the alternate current may sense wrong signals from the direct current circuit and destabilize or even halt the engine. Direct current circuit must be connected according to the drawing provided with the Generator set.
a) The battery can only be connected after all other processes so that the Generator set would not be mistakenly started during the course of installation. When connecting the battery, be sure that the polarity be connected at last to reduce the risk of electric arc.
b) The start system is powered by 24 volt battery current which is usually provided by two 12 volt batteries in series. Ensure that the positive and negative polarities are linked correctly. If the battery is distant from the Generator set, please increase the size of the start cable.
c) Don’t put tools or metal objects on the top of the battery neither let them fall on it.Try to use tools with an insulated handle. If the batteries are seldom used (e.g. as emergency backup), they may discharge and fail to start the Generator set. To solve this problem, our company provides a utility power float charger with the automatic type Generator set to maintain the electricity in the battery. When disconnecting the battery, the utility power to the battery charger must be cut off before disengaging the charge terminal. When fixing the battery to the Generator set, connect the grounding terminal at last while disconnecting it first when removing the battery.
Testing and Adjustment of the Generator set
Before starting the Generator set, please read carefully the technical documents attached to the equipment and make all preparations as necessary.
Generator set Check before Testing
1. Check whether the Generator set surface is clean; check the ground bolts, flywheel screws and screw nuts on rotating parts, tighten them if they are loose.
2. Check the clearance between each component, particularly the clearance for air inlet and outlet valves and depressurizing mechanism).
3. Keep the cylinder in a depressurizing position, rotate the crankshaft while trying to detect any abnormal sounds from the cylinder components. The crankshaft shall rotate smoothly.Meanwhile, pump the oil onto all friction surfaces, close the depressurizing mechanism and rotate the crankshaft to check whether there is any air leakage. If great resistance is met when turning the crankshaft, it means that the compressing works well.
4. Check the protections for the speed governor and overspeeding to get rid of chances of overrev.
5. Check the fuel supply system:
• Ensure that the vent on the fuel tank cap is not clogged or cleaning shall be done to make it clear. Ensure that there is enough amount of diesel fuel which meets the specifications required by the engine. Open the fuel valve.
• Open the depressurizing devices and turn the crankshaft. If clear fuel injecting sound is heard in each cylinder, it means that the injection works well. If no injecting sounds are heard (no fuel sprayed by the injector), it may signal that there is air in the fuel pipe. Slacken the fuel filter and the vent plug of the fuel injection pump to clear off the air.
6. Check the fuel pipe and joints to fix leakage problems if there is any.
Check the cooling system:
• Ensure that there is enough cooling water in the water tank. If the water is insufficient, add soft water to the tank.
7. Check the water pipe joints to fix leakage problems if there is any.
• Ensure that the blades of the water pump moves freely and the drive belt is appropriately tensioned. Press the belt in the middle with hand, it should be possible to depress the belt 10-15mm.
Check the lubricant system:
8. Check the oil pipes and joints to fix leakage problems if there is any.
9. Check the amount of oil in the oil pan. Pull out the dipstick beside the crank case to see whether the oil level is as required. If the oil level is too low, more oil shall be added.If the oil level is too high, careful analysis must be made to find out the reasons. Usually,there are three kinds of reasons for excessive oil.
---Too much oil is filled into the lubricant system
---The diesel fuel intrudes into the crank case and dilutes the oil
---The cooling water intrudes into the oil
• For fill holes where manual power is needed, always fill oil or lubricant grease with oil fillers.
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