CHIWAI Quan Wei Guide

TaiWan QuanWei
Screw-type air compressor
Using and Maintenance
Instructions

Foreword
First of all, Thank you for choosing our Quan Wei screw-type air compressor, I hope it will serve
you well. The products of our company have been inspected and tested strictly before leaving the factory, but
in order to ensure that the machine can be used safely, reliably and durably, the operation and maintenance
personnel are requested to read the instructions carefully before the operation of the unit. Fully grasp the
operational norms and skills of the air compressor group, so that the air compressor in good working
condition for a long time.
If you have something do not understand the contents in this manual, please
contact us as soon as possible, we will serve you wholeheartedly!

Safety attention operation
Please read carefully before operating the air compressor:
1.The ground must be flat and strong in the position of the air compressor, and there should be no
flammable smoke or steam around it, such as thinners for paint, otherwise there will be a fire or
explosion;
2.Installation of pipe welding, should pay attention to prevent welding sparks fall into the air
compressor or splashing into the air compressor cover, avoid burning down some parts of the air
compressor;
3.The power supply line leading to the air compressor must match its power and install the air
switch, fuse wire and other safety devices. In order to ensure the reliable safety of electrical
equipment, there must be grounding device;
4.A very short time before starting the compressor (about 1 second), check the direction of rotation,
must ensure that the direction of rotation of the air compressor is correct, otherwise a few seconds
may cause damage to the compressor air end;
5.The air compressor shall confirm that the power supply has been cut off and the system is not
under pressure when it is overhauled or maintained, and shall mark the warning signs such as
"overhaul" or "no closing" at the power supply;
6.When the unit is in operation, do not loose, remove any pipe accessories, joints and devices. The
unit is filled with high pressure and high temperature liquid and gas, which can cause serious
personal injury accident.
7.The compressor cannot work under the exhaust pressure specified by the nameplate, otherwise
the motor will be overloaded, resulting in the motor and compressor stopping;
8.Before carrying out maintenance (such as re-inject new oil) and maintenance work on the
compressor, it is necessary to:
1) Stopping the unit;
2) Cutting off the power supply to ensure that the compressor is out of power;
3) Ensure that the compressor system is free of pressure.
9.The relief valve is installed on the oil separator seat. Once the gas pressure in the system exceeds
the set pressure, the gas will be released through the valve. Check the cause of over-pressure at this
time;
10.After the air compressor runs for a certain time, the safety valve, temperature sensor, pressure
sensor and other protection systems should be inspected regularly to ensure its sensitivity and
reliability. It is generally inspected once a year;
11.Must use our company designated recommended screw air compressor special oil, prohibit
mixed use of different grades of lubricating oil.

Contents
1.0 General rules and specifications for screw air compressor..........................................................1
2.0 Air compressor installation.........................................................................................................3
3.0 System flow and function of each part.........................................................................................6
4.0 Operating..................................................................................................................................17
5.0 Intelligent controller.................................................................................................................20
6.0 Maintenance and inspection..................................................................................................... 65
7.0 Maintenance and troubleshooting............................................................................................. 70
8.0 Performance parameters........................................................................................................... 74
9.0 Circuit diagram.........................................................................................................................82

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1.0 General rules and specifications for screw air compressors
1.1 Brief introduction of Screw injection Air Compressor
Fuel injection screw air compressor has become the mainstream of the development of air compressor in
the world. It has the characteristics of reliable operation, less easily damaged parts, low vibration, low noise,
low oil content and high efficiency. During the compression process, the compressor continuously injects
lubricating oil into the compression chamber and bearing by virtue of the pressure difference produced by the
compressor itself.
Lubricating oil has three main functions:
1.1.1 Lubricating effect: lubricating oil can form oil film between rotors, avoid contact between rotors and
reduce friction.
1.1.2 Sealing effect: the oil film produced by lubricating oil can seal the compressed air and improve the
volume efficiency of compressor.
1.1.3 Cooling: because the lubricating oil absorbs a large amount of compression heat, the compression
process is close to isothermal compression and the specific power of the compressor is reduced. In addition,
the lubricating oil can also reduce the noise generated by high frequency compression.
1.2 Block structure of Screw Air Compressor
1.2.1 Basic structure
The company uses a screw type air compressor, is a two-axis volumetric type of compressor. The
air inlet is opened at the upper end of the housing, and the exhaust port is opened at the lower part
(some of the air ends are also on top). A pair of high precision main and auxiliary rotors is arranged
horizontally and parallel in the inner part of the housing. The diameter of the main rotor is larger
and the number of teeth is less, the diameter of the secondary rotor is smaller and the number of
teeth is more. The teeth form a spiral around the outer edge of the rotor and the tooth shapes of the
two engage each other. The main and secondary rotors are supported by bearings respectively, one
roller bearing is arranged at the inlet end and two conical roller bearings are installed
symmetrically at the exhaust end. The body is divided into two types, one is belt drive, and the
other is direct transmission. The direct drive system combines the motor power source with the
main body with a coupling, and then increases the speed of the main rotor through a set of high

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precision speed increasing gears. The belt drive type has no speed gear, and two pulleys made in
proportion to the speed of the belt drive the power through the belt.
1.2.2 Meshing
The main rotor is driven by coupling, gear or belt. Because the two rotors engage each other, the
main rotor directly drives the pair rotor to rotate together. The cooling lubricating oil is directly
injected into the meshing part between the rotors by the lower part of the compressor housing
through the nozzle and mixed with the air to take away the heat produced by the compression to
achieve the cooling effect. At the same time, oil film is formed to prevent the direct contact
between metal and metal between the rotor and the gap between the rotor and the housing. The
injected lubricating oil can also reduce the noise caused by high speed compression. Because of the
different exhaust pressure; the fuel injection weight is about 5-10 times the weight of the air.
1.3 Compression principle of Twin Screw Air Compressor
1.3.1 Intake process:
The suction port on the screw inlet side must be so designed that the compressing chamber can fully
inhale, while the screw compressor does not have an intake and exhaust valve set. The intake is only
regulated by the opening and closing of a regulating valve. When the rotor rotates, the tooth groove space of
the main and secondary rotor is the largest when it is turned to the inlet wall opening. At this time, the tooth
groove space of the rotor is connected with the free air of the inlet, because the air of the tooth groove is
completely discharged during the exhaust, and when the exhaust is finished, Tooth groove is in a vacuum
state, when turned to the air intake, the outside air is inhaled, along the axial flow into the main and
secondary rotor in the gutter. When the air fills the entire tooth groove, the inlet side of the rotor turns away
from the inlet of the shell, and the air between the teeth groove is closed. [Intake process]（see figure 1）
1.3.2 Sealing and conveying process:
When the main and secondary rotors are inhale, the teeth summit of the principal and deputy rotors and
the shell are closed, and the air is closed in the teeth groove no longer, that is, [the sealing process]. When
the two rotors continue to rotate, the tooth peak and the tooth groove coincide at the Intake end, and the
anatomists surface moves gradually to the exhaust end, which is the conveying process. [Conveying
process](See figure 2)
1.3.3 Compression and injection process:

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In the process of transportation, the meshing surface gradually moves to the exhaust end, that is,
the tooth groove between the meshing surface and the exhaust port decreases gradually, the gas in
the tooth groove is gradually compressed, and the pressure is increased, which is the process of
compression. At the same time, the lubricating oil is injected into the compression chamber and
mixed with air because of the pressure difference. (See figure 3)
1.3.4 Exhaust process:
When the meshing end of the rotor moves to communicate with the exhaust of the housing, the
compressed gas begins to discharge until the meshing surface of the tooth peak and the tooth
groove moves to the exhaust end, At this time, the tooth groove space between the meshing surface
of the two rotors and the exhaust port of the housing is zero, that is to say, the complete (exhaust
process), at the same time, the length of the tooth groove between the rotor meshing surface and the
inlet of the housing reaches the longest, and the suction process is going on again. (See figure 4)
Figure 1 Figure 2 Figure 3 Figure 4
2.1 Installation
2.0 Air compressor Installation
Attention before installation：
2.1.1 Before installation, check whether the package box is intact or not, and check whether the
part of unit is damaged. The handling and installation of the unit after opening the box should be
strictly carried out in accordance with the relevant handling matters. There are two forklift holes
under the base of the unit. When forking is carried out, the wooden cushion should be placed to
prevent the forklift truck from crushing the door plate of the unit (see chart). If you use a sling, be

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sure to use a crossbar, which can counteract the side pressure of the sling to the box. Note: it is not
advisable to pad some protective material between the sling and the sound isolating cover of the
unit, which will crush the door plates on both sides of the unit.
2.1.2 The selection of the air compressor installation site is most neglected by the staff.
Often without a plan find a random position, Use immediately after pipeline. Little did they know
that such sloppy behavior had possible caused the consequences of future failures in air
compressors, difficulties in maintenance, and poor quality of compressed air. Therefore, the proper
installation site is a prerequisite for the correct use of the air pressure system.
2.1.3 It is necessary to have a wide and well-lit place to facilitate operation and maintenance.
2.1.4 The relative humidity of the air should be low, the dust is less, and the air is clean and well
ventilated.
2.1.5 The ambient temperature shall be less than 45 degrees Celsius, because the higher the
ambient temperature, the less air the air compressor will output.
2.1.6 If the environment of the factory is poor and the dust is high, the service life of the air
compressor system parts should be maintained by installing the pre-filter equipment.
2.1.7 Reservation of access roads and installation of cranes for maintenance and repair. (High
power air compressors in particular needed it)
2.1.8 Reserve maintenance space, air compressor and wall must have at least 70 cm or more
distance.
2.1.9 The air compressor is more than one meter away from the top space.
2.1.10 Refer to GBJ29-90 "Design Specification for compressed Air stations".
2.2 Matters needing attention in piping, foundation and cooling system
2.2.1 Matters needing attention in air piping
1) When the main piping is installed, the piping must have a 1-2 degree inclination so that the
condensed water in the piping can be discharged.

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2) The pressure drop of the piping shall not exceed 5% of the set pressure of the air compressor.
Therefore, it is better to use a larger diameter than the designed value when piping.
3) The branch line must be taken out from the top of the main line to prevent the condensed water
in the line from flowing into the working machine or back into the compressor.
4) The tools to be lubricated should be equipped with a triple combination (air filter, voltage
regulator, oil feeder, etc.) in order to improve the service life of the tool.
5) Do not shrink the road arbitrarily. If it is necessary to narrow or enlarge the pipe, use the tapered
pipe, otherwise there will be turbulence at the joint, which will lead to a large pressure loss, and
have a great impact on the life of the pipe.
6) If there are purifying and buffering facilities such as air storage tank and dryer after air
compressor, the ideal pipe should be air compressor + gas storage tank + dryer. The gas storage
tank can filter out part of the condensate water, and the gas storage tank also has the function of
reducing the exhaust temperature of the gas. Lower temperature and less moisture content can
reduce the load of the dryer by re-entering the dryer.
7) If the air consumption of the system is very large and the time is very short, it is best to add an
air storage tank as a buffer, which can reduce the number of empty loads of the air compressor,
which is of great help to the air compressor.
8) For compressed air under the system pressure below 1.5MPa, the velocity of flow in the
conveying pipe shall be below 15m/sec to avoid excessive pressure drop.
9) Minimize the use of bends and valves in the pipeline to reduce pressure loss.
10) The ideal pipe arrangement is for the main pipeline to surround the whole plant, so that double
compressed air can be obtained at any location. If the amount of gas used in a branch line increases
suddenly, the pressure drop can be reduced. Suitable valves are arranged on the annular main line
to facilitate overhaul and cut off.
2.2.2 Basis
1) The foundation should be built on hard soil, and the foundation plane should be smooth ground
before installation to avoid vibration of the air compressor.
2) If the air compressor is installed upstairs, it must do a good anti-vibration treatment to prevent
the vibration from spreading to the downstairs, or to produce resonance. There are safety considers

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about the air compressor and the building itself.
3) The vibration produced by the spiral air compressor is very small, so it is not necessary to make
concrete foundation, but the ground should be flat and the ground must not be soft soil.
2.2.3 Cooling system
1) Cooling water for water-cooled air compressors is best used soft water to prevent calcium
and magnesium ions in the water from reacting due to high temperatures, forming scale in the
cooler and affecting the heat transfer effect of the cooler. If cooling tower circulation system is used,
the water must be regularly softened to keep the water clean. The cooling water requirements are as
follows:
A) suspended matter ≤100 mg / L.
b) PH value: between 6.5- 9.
C) the hardness of silver carbonate is ≤140. (when drainage temperature is 45 ℃).
2) The automatic recharge system of the cooling water circulation system must be perfected;
otherwise, the cooling water quantity will be insufficient after running for some time, which will
cause the air compressor to jump off because of the high temperature. Cooling towers need to be
easy to dissipate, have good ventilation, and must be fixed to prevent them from tilting.
3) The water pressure of cooling water shall generally be maintained between 0.15-0.25MPa. No
greater than 0.4Mpa.
4) The cooling water outlet temperature should be kept below 40 °C, and the temperature
difference between incoming and outgoing water should be 6-10 °C.
5) In the case of air-cooled air compressors, attention should be paid to their ventilation
environment. Air compressors shall not be placed in the vicinity of high-temperature machinery or
in a poorly ventilated confined space so as not to cause the phenomenon of hopping as a result of
excessive exhaust temperature. If used in a closed system, additional pumping and exhaust
equipment shall be installed to facilitate air circulation, Generally speaking, the single air volume
of its extraction and exhaust air should be greater than that of the air compressor heat dissipation
and exhaust air.
2.3 General specification and safety code for electrical appliances
2.3.1 According to the power of the air compressor, choose the correct power line diameter, do not

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use too small diameter, otherwise the power line will be easily burned out at high temperature and
occur accident.
2.3.2 It is best to use a set of electric power systems alone, especially to avoid parallel use with
other power consumption systems, which may cause the protection device to jump in action due to
excessive voltage drop or unbalanced three-phase current, resulting in overload of the air
compressor. The high power air compressor should pay special attention to this.
2.3.3 Chosen the appropriate NFB (no fuse switch) according to the KW number of air compressor
to maintain the electric power system and the safety of repair and maintenance.
2.3.4 The correctness of the voltage of the air compressor should be confirmed when it is
distributed.
2.3.5 The ground wire of the motor or system should be erected, and the ground wire can not
be directly connected to the air or cooling water pipe.
2.3.6 Under normal circumstances, the three-phase AC motor is overloaded and the current must
not exceed 10% of the rated current. If the three-phase current is unbalanced, the ratio of the lowest
phase current to the highest phase current must not exceed 10%. At the same time, if there is a
voltage drop, the voltage drop must not be less than 5% of the rated voltage.
2.3.7 The air compressor must pull a connection to the ground to prevent the leakage of
electricity.
3.1 System flow chart
3.0 System flow and function of each part

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3.2 System flow
3.2.1 Air flow description
1) After the dust is filtered out by the air filter, the air is compressed into the compressing bin
through the intake valve, and mixed with the lubricating oil, the compressed air mixed with the oil
enters the oil cylinder, and then through the oil fine separator, the pressure maintenance valve, the
rear cooler, Air-water separator, into the use of the system.
2) Functional description of each component in the main gas source path:
A): Air filter
Air filter is a dry paper filter, the filter paper fine porosity is about 10um, usually every 600-1000
hours (depending on the environment) should be removed from the surface of the dust removal
method is to use low-pressure air dust from the inside to outside. Some air filters are fitted with a
differential pressure transmitter or a pollution indicator as required. If the display panel shows a red
line in the air filter clogging or contamination indicator, it means that the air filter must be cleaned
or replaced.
B): Intake valve
a) When starting, the intake valve is in the closed state, which makes the compressor start under
low load, lightens the load of the motor when starting, and is convenient for the normal operation
of the motor. At the same time, the inlet valve body has no air intake hole, which avoids the over-
vacuum in the compressor body. And can quickly establish the system required air pressure.
b) Empty car, heavy car conversion
After the compressor starts, the inlet valve opens. The compressor is converted into a heavy vehicle
state, that is, a normal working state.
c) Shutdown pressure relief and non-return function
After stopping, the inlet valve can quickly remove the air pressure of the oil and gas barrel, so that
the next starting motor will not overload; at the same time, it can prevent the compressed air flow
back in the oil and gas barrel, resulting in the rotor reversal and the oil-bearing air being ejected
from the air filter.
3) Temperature sensor

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In the case of water loss, oil loss, lack of water, lack of oil, etc., the exhaust gas temperature may
be too high. When the exhaust gas temperature reaches the set temperature, the system will
automatically stop. The tripping temperature is generally set at 105-110°C, and the exhaust
temperature can be read on the LCD panel.
4) Oil and gas drums
Oil level indicator is installed on the side of oil and gas barrel. The oil level of static lubricating
oil should be between the high oil level line of the oil level meter and the low oil level line. There
is a drain valve under the barrel. Before starting, the valve should be twisted slightly to remove the
condensate water in the barrel. Note: once there is oil flow out, close the drain valve
immediately to avoid excessive lubricating oil outflow. The barrel has a refueling hole, which
can be used for refueling.
5) Oil separator
See the instructions in the following section for more details.
6) Safety valves
When the system pressure is set improperly or out of order, the pressure inside the oil and gas
barrel is higher than 0.1Mpa than the set exhaust pressure, the safety valve will jump away, so that
the pressure will drop below the set exhaust pressure. The safety valve has been adjusted before
leaving the factory. Please do not adjust it at will.
7) Discharge valve
The relief valve is a mechanical emptying valve installed on the inlet valve. When stopping or
empty the valve opens to discharge the pressure in the barrel to ensure that the compressor can start
or operate under no load.
8) Pressure maintenance valves (also known as minimum pressure valves and pressure retaining
valves)
Located at the outlet of the oil separator above the oil and gas barrel, the opening pressure is set
at about 0.45Mpa, the function of the pressure maintenance valve is: a) When starting, priority is
given to establishing the circulating pressure required for the lubricating oil to ensure the
lubrication of the body.
b) When the pressure exceeds 0.45 Mpa, it can reduce the air flow rate of the oil separator,

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ensure the effect of the oil separator, and protect the oil separator from being damaged by the huge
pressure difference.
9) Rear cooler
A) If that is an air-cooled-type cooler, cold air is drawn in using a cooling fan, and the
compressed air is cooled by the cooler. Its exhaust temperature is generally below (atmospheric
temperature +10°C). The air-cooled air compressor is more sensitive to the environmental
temperature conditions, when choosing the place to place, it is best to pay attention to the
ventilation conditions of the environment.
B) If that is water-cooled type models, use a shell cooler to cool compressed air with cooling
water. Its exhaust temperature is below 45°C (cooling water inlet temperature must not exceed
35°C). The water-cooled air compressor is insensitive to the ambient temperature conditions, and it
is easy to control the exhaust temperature. If the cooling water quality is too poor, the cooler is
liable to scale and block. Special attention must be paid.
10) Air-water separator
The centrifugal structure of cyclone can remove the moisture, oil droplets and impurities
condensed after air cooling. The compressed air is slightly opened through the regulating valve
under the air-water separator to make the condensed water flow out, without causing a large
amount of air leakage. The company's products have automatic drainage and manual drainage for
the user to choose.
3.2.2 Lubricating oil flow description
Because of the gas pressure in the oil and gas barrel, the lubricating oil is pressed into the oil
cooler. After cooling the lubricating oil in the cooler, the impurity particles are removed through the
oil filter, and then divided into two paths, and the lower end of the body is injected into the
compression chamber all the way. Cooling compressed air, the other way to both ends of the body,
used to lubricate the bearing group and transmission gear, and then (lubricating oil in each part)
gathered in the compression chamber, with the compressed air discharge. The compressed air
mixed with oil enters the oil barrel, separating a large part of the oil, and the remaining oil mist air
passes through the oil fine separator to filter out the remaining oil, and after the pressure
maintenance valve enters the rear cooler to cool, it can be sent to the service system.

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1）Functional description of each component on the Oil Road
A) Oil cooler
The oil cooler and the air after cooler have the same cooling method. There are two types of air
cooling and water cooling. If the environmental conditions are not good, the fins of the air-cooled
cooler are susceptible to dust and affect the cooling effect. The exhaust temperature will be too
high and tripping. Therefore, for each period of time, apply compressed air to dust off the fin
surface, if it cannot be blown clean, must be cleaned by solvent, and must keep the coolers
surface clean. When the tube and shell cooler is plugged, it must be soaked with special potion,
and the fouling of the clogged pipe must be removed mechanically. Be sure to clean it
completely.
B) Oil filter
Oil filter is a paper type filter, whose function is to remove impurities such as metal particles,
oil degradation and so on. The filter accuracy is between 5u-10u and has perfect protection for
bearing and rotor. Whether the oil filter should be replaced or not can be judged by its pressure
difference indication and operation time. If the pressure difference indicator light is on, the oil
filter stopper must be replaced. After the first 600 hours of operation of the new machine, the
oil and oil filters need to be replaced, Then it will replaced according to the light or running time
of the differential pressure indicator lamp. If the pressure difference of the oil filter is large and it is
not replaced, it may lead to insufficient oil intake, and the exhaust high temperature hopper will
affect the bearing life because of the lack of oil quantity at the same time.
C) Oil separator
The filter core of the oil fine separator is made of multi-layer fine glass fiber. The foggy oil
and gas contained in compressed air can be almost completely filtered out after passing through the
oil fine separator. Under normal operation, the oil separator can be used for about 3000-4000 hours.
However, the oil products of lubricating oils and the degree of pollution of the surrounding
environment have a great impact on their life. If the environmental pollution is serious, you may
consider installing a front air filter; as for the choice of lubricating oils, Must use our company
screw air compressor special high grade lubricating oil, most avoid using false oil or mixed oil.
The outlet of the oil separator is provided with a safety valve and a pressure maintenance valve,

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from which the compressed air is drawn to the rear cooler. The oil filtered by the fine separator is
concentrated in the small circular groove in the center, then returned by the oil return pipe to the
throttling check valve into the intake side of the main engine for circulation, so that the filtered
lubricating oil can be prevented from being discharged with the air again.
D) Temperature control valve
A temperature control valve is installed in front of the cooler, the function of which is to
maintain the exhaust temperature above the pressure dew point temperature. When the oil is just
turned on, the temperature of the lubricating oil is low. At this time, the temperature control valve
will automatically open the return circuit, and the oil will enter the air end directly without passing
through the oil cooler. If the oil temperature rises to 60-71 ℃, the valve slowly opens to 75-85 ℃,
the oil will go through the oil cooler into the body.
3.2.3 Cooling system
1) Air-cooled model
The cold air is pumped in by an axial fan and blown through the fin of the cooler to exchange
heat with compressed air and lubricating oil to achieve the cooling effect. The maximum
allowable ambient temperature of this cooling system is 45 ℃. If the system exceeds, it is
possible to cause tripping, such as placing the place at the edge of the high temperature boiler.
2) Water-cooled model.
The design standard of cooling water temperature is 32 ℃, so the design of cooling water
circulation system must be paid special attention. In particular, cooling water quality must meet
the general industrial water standards before the use of groundwater as far as possible. If the
water quality is poor, the cooling tower should be regularly cleaned with cleaning agent to avoid
affecting the efficiency and longevity of the cooler. In winter, the normal temperature is under
the 0 ℃.The cooling water in the cooler must be drained clean after the unit is shut down.
Otherwise, it will freeze and crack the cooler.
3.3 Safety protection systems and warning devices
3.3.1 Motor overload protection
There are two main motors in the air compressor, one is the motor driven by the air compressor,
and the other is the cooling cycle fan motor. Under normal conditions, the motor's operating current
will not exceed the rated current of 10% (for example, because of voltage drop, three-phase
imbalance and other factors). When the operating current of the motor exceeds the upper limit set
by the electric protection device, the over-current protection device will automatically cut off the
main power supply and the air compressor will stop.

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Causes of overloading of general motors:
1) Artificial operational errors: such as self-adjustment of exhaust pressure, improper system
adjustment, etc.
2) Mechanical failure:
Such as the internal loss of the motor, motor under phase operation, safety valve non-action,
system setting failure, oil separator blocking and so on.
If the motor is found to be overloaded in operation, contact the manufacturer immediately and use
the phone or video to check and find out the cause, Prevent motor burning out loss too much.
3.3.2 Excessive protection of exhaust temperature
The maximum exhaust temperature set by the system is 105-110 ℃. If it exceeds, the power
supply will be cut off by the system itself. There are many reasons why the general exhaust
temperature is too high, but the most common cause is the failure of the oil cooler. If the air-
cooled oil cooler is blocked by dust, the lubricating oil will gradually rise and cause the high
temperature stop if the cold air can not pass freely through the cooler. Therefore every once in a
while must use the pressure air to remove the heat dissipation fin on the dust, if the fin on
the plug matter cannot blow clean, had better use the clean liquid or the volume agent to clean.
Water cooled air compressor is generally due to cooling copper pipe fouling blockage resulting in
reduced heat transfer efficiency and high temperature tripping. The highest ambient temperature
of air compressor design is 45 ℃. If the ambient temperature is higher, the exhaust temperature
is higher. Therefore, it is necessary to choose a place with low ambient temperature and good
ventilation to place the air compressor. When the intelligent controller detects that the
temperature exceeds the set value, the power supply is cut off automatically. The system cannot
be booted again at this time unless you reset it once. In order to avoid overheated shutdown as
far as possible, the system is equipped with an early warning device. When the exhaust
temperature reaches 100-105 ℃, the controller will issue a warning signal to alert the operator.
3.3.3 High exhaust pressure protection.
When the exhaust pressure of the system exceeds the rated exhaust pressure 0.5bar, the power
supply will be cut off by the system itself. When the volume of air is zero (the valve is closed)
and the discharge is less than the intake, the pressure of the system will rise rapidly and cause the

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relief valve to move out of air. In order to avoid the frequent operation of the safety valve and
increase the safety factor of the machine, it is necessary to set up this protection.
3.3.4 Oil pressure protection (User selection)
When the oil pressure of the system is lower than 0.15-0.2Mpa, the pressure switch signals the
motor to stop running and protect the air end from oil shortage and burn.
3.3.5 Alarm device
There are three kinds of alarm devices: air filter blocking, oil filter blocking, oil separator
blocking. (Greater then132Kw)
They are displayed on the LCD panel. When the panel has a fault indication, that is, a filter has
been blocked, the user must in the shortest time to replace the spare goods, and otherwise it will
affect the performance and safe operation of the air compressor.
3.4 Control system and electrical circuit
3.4.1 Control system
1) Motor starting (step-down or Y operation).
During this period, the (three-phase) solenoid valve shall not be electrified, the intake valve shall
be completely closed, and the emptying valve shall be fully opened, at which time the inlet side
shall become a vacuum, and the lubricating oil required for the compressor and bearing shall be
ensured by the pressure difference between the compressing chamber and the oil and gas barrel.
2) Full voltage motion of motor (full voltage or △Operation).
When the pressure in the oil and gas barrel gradually rises above 0.15Mpa, the inlet valve is
completely open, so the pressure in the oil barrel increases rapidly and the compressor starts to
operate at full load. When the pressure rises to 0.45~0.50Mpa, the minimum pressure maintenance
valve is fully open and the air output.
3) Heavy / no-load operation
When the exhaust pressure reaches the upper limit of the system, the power supply (three-phase)
solenoid valve is cut off, and the intake valve is closed. At the same time, the exhaust valve is
completely opened, and the air in the oil and gas barrel is discharged into the atmosphere. At this
time, the compressor operates in a no-load state. The required lubricating oil is ensured by the
difference between the pressure in the compression chamber and the oil and gas tank. When the
pressure of the pipeline system falls below the limit set by the system, the power supply (three-
phase) solenoid valve is again opened, the intake valve is also fully open, the discharge valve is
closed, and the compressor is reloaded.

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4) Tolerance operation (OLG100 / 380)
When the exhaust pressure gradually rises and does not reach the upper limit set by the system,
the set pressure of the pressure-regulating valve is first reached, so that the intake valve is gradually
closed. At this point the system has begun to adjust. If the pressure continues to rise, the intake
valve closes gradually until it is completely closed. On the contrary, if the pressure of the system
decreases gradually, the intake valve opens gradually and the intake volume and pressure increase
gradually, until it is lower than the set value of the stabilizer valve, then the adjustment action stops.
If the gas consumption of the system decreases much, the pressure rises too fast, and its speed
exceeds the capacity adjusting reaction ability, the pressure sensor gives a signal to the controller,
which will cause the three-phase solenoid valve to lose power, the intake valve to close, and the air
compressor to unload. When the pressure is lower than the system set pressure value, the three-
phase solenoid valve is energized, the intake valve is opened, and the air compressor resumes heavy
load operation.
5) Fan start-stop control
After the air end starts, the fan motor does not run temporarily, when the exhaust temperature
reaches 80-85 ℃, can be set on PLC). The fan motor will start automatically. When the
temperature drops to 70°C, the fan motor will stop running. On the one hand can save electricity,
on the other hand can make exhaust temperature in a short time to reach the temperature above dew
point, this is particularly important in the winter humid areas, as much as possible to make the air
moisture does not precipitate.
6) Shutdown
After pressing the stop button, the solenoid valve is shut down, at the same time the discharge
valve is completely opened, and the air in the oil barrel is discharged into the atmosphere. After 10-
15 seconds delay, when the pressure in the barrel drops to a certain value, the motor stops running.
7) Emergency shutdown
When the exhaust temperature exceeds 105-110 ℃or when the motor over current protection
device due to overload, the power supply will be cut off, the motor will stop running immediately
without delay, and the (three-phase) solenoid valve, the intake valve will also be closed, and the