Rotair MDVN 71 AP User manual

MANUALE DI USO E MANUTENZIONE - RICAMBI
MANUEL D’ENTRETIEN - PIECES DE RECHANGE
OPERATING MAINTENANCE - PARTS MANUAL
BEDIENUNG UND WARTUNGSANLEITUNGEN
MANUAL DE USO Y MANTENIMIENTO - RECAMBIOS
MOBILE MOTOR COMPRESSOR
MDVN
71 AP
Via Bernezzo 67 –12023 CARAGLIO (CN) –ITALIA
TLF: [phone] –FAX: [phone]
E-MAIL: [e-mail]
http://www.rotairspa.com
MAN MDVN 71 AP INGL 05-05-09 rev 01

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SUBJECT INDEX
1) Identification data _
2) Technical data _
3) Manual use and consultation _
4) Envisaged machine use _
5) Technical description of machine and its function _
5.1) Chassis and axle _
5.2) Bodywork _
5.3) Motor _
5.4) Compression unit _
5.5) Oil separator tank _
5.6) Bell and flexible coupling _
5.7) Control instruments and devices _
5.8) Wiring system and its function _
5.8.1) Safety devices _
5.9) Oleopneumatic plant and its function _
5.9.1) Lubrication circuit _
5.9.2) Pneumatic circuit _
5.9.3) Automatic regulation of the motor speed _
6) Machine handling and parking _
6.1) Lifting instructions _
6.2) Towing instructions _
6.3) Transport instructions _
6.4) Parking instructions _
7) Instructions for machine use _
7.1) Before starting the machine. Check the motor and compressor oil levels _
7.2) Starting up _
7.3) During the working stage _
7.4) Stopping _
7.5) After machine stop _
8) Machine setting and tuning _
8.1) Checking and setting of motor speeds _
8.2) Checking and setting of maximum final pressure _
8.3) Checking and setting of minimum pressure _
8.4) Safety valve check _
9) Maintenance programme _
9.1) Daily checks _
9.2) Weekly checks _
9.3) Three-monthly checks _
9.4) Annual checks or when total number of hours is reached _
10) Periodic maintenance _
10.1) Checking and cleaning of air suction filter _
10.2) Battery check _
10.3) Tyre pressure check _
10.4) Cooling radiator cleaning _
10.5) Checking and cleaning of the oil recovery nozzle _
10.6) Fuel tank drainage _
10.7) Braking device check _
10.8) Wheel screw checking _
10.9) Compressor oil filter replacement _
10.10) Compressor oil replacement _
10.11) Checking and replacement of the oil separator element _
11) Problems : causes and remedies _
12) Spares_

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-- 1) IDENTIFICATION DATA --
Here follows details of the information printed on the machine identification plate situated
at the front of the machine.
MODEL: MDVN 71 AP
REGISTRATION NO.:
MASS (Kg): 1240
AIR DELIVERY (litres per minute) * : 7100
WORKING PRESSURE (bar): 7
YEAR OF CONSTRUCTION:
ACOUSTIC POWER dB(A) ** : < 100
(*)Measured in accordance with ISO 1217 standards (±5%).
(**)Measured in accordance with directive CEE 84/533, technical adaptation 85/406/CEE.
CAUTION:
The use of non-original ROTAIR spares will result in the immediate cancellation of
the guarantee.
On requesting assistance or ordering of parts always cite the model number and
registration number above.

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-- 2) TECHNICAL DATA --
COMPRESSOR:
-- WORKING PRESSURE: 7 bar
-- MAXIMUM FINAL PRESSURE: 8 bar
-- MINIMUM WORKING PRESSURE: 5 bar
-- AIR YIELD AT MAX SPEED
AND ON WORKING PRESSURE: 7100 litres/1’
-- COOLING: hydraulic oil (*)
-- OIL SYSTEM CAPACITY: 13 litres
(*) Q8 SCHUBERT 46 oil is recommended.
Similar types permitted: DICREA 46 AGIP
COMPRESSOR OIL 46 API
ENERGOL RC-R 46 BP.
COMPRESSOR 46 ERG.
RARUS 425 MOBIL.
SCARLATTI 46 Q8
LR CCW 46 ROLOIL.
CORENA D 46 SHELL
DACNIS VS 46 TOTAL.
MOTOR:
-- MODEL: PERKINS 804-D33
-- NUMBER OF CYLINDERS: 4
-- AVAILABLE POWER: 47 KW (63,9 HP)
-- COOLING: liquid type
-- MAX. ROTATION SPEED: 2500 r.p.m.
-- MIN. ROTATION SPEED: 1650 r.p.m.
-- ELECTRICAL SYSTEM TENSION: 12 Volt
For all other information, regarding the motor, consult the use and maintenance booklet of
the manufacturer itself, enclosed with this documentation.
COMPLETE MACHINE:
-- MAX. ENVIRONMENTAL TEMPERATURE: 40 °C
-- LENGTH (excluding drawbar): 2150 mm
-- WIDTH: 1590 mm
-- HEIGHT: 1592 mm
-- WEIGHT IN WORKING
CONDITION (approximate): 1240 Kg

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-- 3) THE PURPOSE OF THE MANUAL AND WHO IT IS TO BE CONSULTED BY -
The owner, user and maintenance technician must carefully study the manual
to ensure that it is used for the purposes for which it has been designed and constructed.
It is essential that all the information contained in this manual are applied, in
order to ensure optimum use of the machine under the safest conditions.
This manual fully describes:
- the information concerning the drawing, lifting and parking of the
machine;
- the general standards and useful advice for both ordinary and
special maintenance;
- the means for the identification and ordering of spares.
NB: The instructions for correct motor use are provided by the
motor manufacturer itself.
The correct and careful use of the machine in accordance with the instructions
contained in this manual, will ensure the long life of the machine, and will also enable the
personnel to prevent the risk of any accidents or injury during work.
This manual must be careful conserved, in its special case, away from any
humidity, heat and sun's rays, to ensure that it is ready for consultation at any time, both
by the operational personnel and the maintenance staff.
It is important to ensure that the special maintenance operations in particular
are undertaken by specialized personnel.
In the event of loss or damage of this manual, ROTAIR must be asked for a
copy, citing the relative machine identification details as shown on the plate on the
machine.
Should the plate become illegible, use the details quoted on the invoice on
requesting a new manual.
Further information or instructions for use or relating to any further interventions
necessary on the machine can be request ROTAIR SPA directly, always citing the
machine identification details.
This machine has been exclusively designed and built to supply compressed
air in the conditions as envisaged by the manufacturer. Any other use not envisaged in
this description will be considered as being "non conforming" and will release the
manufacturer from any further responsibility which will fully that of the user itself.

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“Conforming use" presupposes the observance of the following regulations
concerning the use, maintenance and transport of the unit itself.
It is also necessary to ensure that all the accident prevention regulations hereby
described are followed, also in accordance with general safety regulations as indicated in
the current legislation.
The constructor declines any responsibility in the event of any modifications
made to the machine without its authorization.
The machine is supplied complete with the following documents:
1) - General use and maintenance booklet;
2) - Motor use and maintenance booklet;
3) - Declaration of machine conformity to the R.E.S. of EEC directive 89/392;
4) - Conformity certificate of the oil separator tank;
5) - Certificate of homologation for road circulation (should this have been envisaged and
requested in the sales contract);
6) - Instructions booklet for the axle and the drawbar;
7) - Certificate of conformity of the safety valves of the oil separator tank;
8) - Motor guarantee certificate;
9) - Compressor guarantee certificate.
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-- 4) ENVISAGED MACHINE USE --
The MDVN motor-driven compressor is a machine which generated a well-
defined quantity of compressed air measures in litres per minute.
There are many field of application for the use of all those tools, accessories
and implements which have a "pneumatic" function such as demolition hammers,
perforation hammers, vibrators, drills, starters, compactors, plasterers, etc...
Each instrument has a compressed air consumption measured in litres per
minute.
The best ratio between compressor and tool is when the compressed air
consumption of this last does not exceed 85% of the air generated by the compressor
(also bear in mind that the quantity of compressed air requested by the tool, will increase
in proportion to the wear of the tool itself).
A correct compressor-tool ratio will ensure that the machine operates efficiently
and will guarantee maximum performance.
If the tool is too big it will jeopardize the correct function of the machine, and its
performance will be impaired, not having the necessary amount of compressed air.
This machine has been designed to work at an environmental temperature of
between -10 and +40C.
The compressed air generated by this unit contains minute traces of oil and it is
therefore not suited to use in those systems that require totally oil-free air (i.e. food
industry, pharmaceutical industry, flour and powder transport, etc...).
COUNTER-INDICATIONS

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GENERAL PRECAUTIONS
1. The machine owner is responsible for ensuring that the compressor is maintained
in such conditions as to ensure totally safe operation. Any parts or accessories
which fail to guarantee safe function are to be replaced.
2. Use only the oils and lubricants recommended or approved by ROTAIR S.p.A. and
the engine manufacturer. Ensure that the selected lubricants comply with all current
safety provisions, particularly as regards explosion or fire risks, and the hazard of
the decomposition or production of harmful gases.
3. The supervisor or the responsible party must ensure that all the instructions
concerning the function and maintenance of both machinery and equipment are
always carefully followed, and that the machines and all the related accessories
and safety instruments, comprising the entire compressed or vacuum air system
together with all the related piping, valves, connectors and hoses as well as the
expendable elements are in good conditions, that they are not excessively worn
and that they are not mishandled.
4. All maintenance, overhauling and repair operations are to be undertaken
exclusively by adequately trained staff, and supervised by a person qualified in
these types of operations if necessary.
5. In the event of suspected or evident overheating of an internal machine
component it is necessary to stop the machine, but do not open any inspection
hatch before the necessary cooling time has elapsed, to prevent the risk of the
spontaneous combustion of oil vapours on contact with incoming air.
6. Maintenance operations which do not form part of the standard maintenance
program, can only be undertaken with the machine at a complete standstill.
7. Before proceeding to disassemble any pressurized component, the compressor,
or the machine needs to be suitably isolated from all pressure sources and should
be totally exposed to the atmosphere. Each isolation valve must display a warning
sign with the wording “work in progress: do not open”.
8. Before proceeding with repair work it is necessary to take all the necessary
precautions to prevent the risk of sudden starting up. All the starter instruments
must also bear a sign with the following wording “work in progress. Do not start up”.
The battery should be detached and removed or the terminals should be covered
with insulating caps.
9. Never allow the machine or appliance to operate at beyond the established limits
(in terms of pressure, temperature, speed, etc..)
10.The machines and pneumatic appliances are to be kept clean , and free of oil, dust,
or other accumulated dirt.
11.To avoid the risk of the building up of excessive working temperatures, the heat
transfer surfaces must be regularly inspected and cleaned (including cooling fins,
coolers and the water jackets, etc). A suitable programmed cleaning frequency
should be established for each machine.
12.All the regulation and safety instruments must be maintained with the greatest care
to ensure their correct function and they must not be placed out of use.
13.Beware of damaging the safety valves and other pressure discharging instruments,
obstruction by means of varnish, oil residue or accumulated dirt is to be avoided as
it may effect the working efficiency of the instrument.

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14.The precision of the pressure and temperature indicators should be regularly
checked in order to ensure rapid replacement should the tolerance values be
irregular.
15.The parts should be replaced solely using original ROTAIR S.p.A. spares.
16.The safety instruments are to be tested as described in the maintenance table in
the instructions manual in order to ensure that they are in good operating
conditions.
17.Never use any inflammable solvents or carbon tetrachloride to clean the parts.
Take the necessary precautions to protect against toxic vapours when cleaning
using specific chemical products.
18.Always pay the greatest care to cleanliness in all the maintenance and repair
operations. Always protect against dirt by covering the parts and exposed openings
with a clean cloth, paper or adhesive tape.
19.Protect the engine, alternator, air intake filter as wells the regulation and electrical
components etc to prevent the risk of humidity seeping in, for example during
steam cleaning operations.
20.During operations involving either heat, flames or sparks in a machine, the
surrounding components must be protected with non-inflammable material.
21.Never use a live flame luminous source to inspect the inside of a machine,
pressure container etc.
22.In the case of transportable elements, support the tow bar and axles in a secure
manner, should it be necessary to work under the machine or on wheel removal.
Do not rely solely on the jacks.
23.Before dismantling a compressor, engine or other machine or before beginning an
overhaul operation ,avoid moving mobile parts weighting over 15 kg.
24.Once the repairs are complete ensure that no tools, cloths or components have
been left inside or on top of the machine, engine or drive elements.
PRECAUTIONS DURING USE AND FUNCTION
Before lifting a unit, all the loose or rotating parts must be firmly secured. Do not apply any
cables, chains or ropes directly to the lifting eyebolt, but apply a crane hook or a lifting
shackle in compliance with local regulations.
The use of a lifting eyebolt for lifting by means of helicopter is prohibited.
Remaining in a risk zone beneath a raised load is severely prohibited.
All lifting acceleration and deceleration movements must be kept to within safety limits.
1. Before towing the compressor:
-ensure that the tank has been depressurised;
-check the tow-bar, the braking system and the towing hook. Also check the
hitching system of the towing vehicle.
-Check that the pivoting wheel and the parking pin are locked into raised position;
-Ensure that the towing eyebolt is free to rotate around the hook;
-Check that the wheel nuts are fully tightened and that the tyres are in good
condition and at the right pressure;
-Connect the headlight cable and check all the lights;
-Remove the wedges that block the wheels, if they have been applied and release
the parking brake.
2. Never exceed the maximum compressor towing speed.

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3. Position the unit on flat ground and lock the parking brake before releasing the
unit from the towing vehicle. Should the compressor not feature a parking brake,
immobilise the compressor by placing some wedges in front or behind the wheels.
4. The operator should avoid getting in the way of any released compressed air as
the force of the air speed may cause injury to those directly in its path. Never direct
the air jet directly onto your own body or anybody else. Never use compressed air
to dry your garments.
5. Should it be used for cleaning equipment, proceed with extreme caution using
protective goggles.
6. Should the machine need to operate in closed environments, it is necessary to
convey the exhaust gas to the exterior using a special duct pipe (a stainless steel
spiral pipe is recommended with a diameter of at least 60 mm, the length of which
should be as short as possible. It is also necessary when working in closed
environments to create a ventilation system that conveys the any dirty, hot or dust
saturated air externally, to ensure that the machine can take in air that is fresh and
clean.
7. However the operation of the machine in any closed environments with
atmospheric conditions in which it is possible to find corrosive or explosive gas
vapours or mixtures is severely prohibited.
8. When operating in open areas it is necessary to position the machine in such a
way as to ensure that on exit of the discharge gas it occurs on the lee side and
never in the direction of walls or other obstacles, which might oppose the exit and
the dispersion of such exhaust gases.
9. When undertaking any demolition, drilling or sandblasting operations or any
similar operations that tend to generate dust, the tool needs to be connected to the
compressor used a flexible hose that is pressure resistant and of sufficient length to
permit the machine to be distanced from the working area, thereby avoiding the risk
of any clogging of either the suction filters on the unit or of the cooling radiator used
to cool lubricant and coolant liquids. Once again the operator should ensure that
the machine is positioned leeward in relation to the working area.
10.The machine has been designed and constructed to work with bonnet lowered and
therefore it must not be kept raised with the engine running, because as well as
generating high noise levels which are harmful it would also jeopardize the
necessary internal ventilation that is essential to ensure correct compressor
function.
11.Position the machine away from the walls and take all the necessary precautions to
ensure that the hot air discharged from the engine and from the cooling systems is
not recycled. Should it be conveyed back into the engine or ventilator there is a risk
of machine overheating.
12.When selecting flexible hosing to connect the machine to the tool, it is important to
ensure that they are of the correct dimensions, in terms of length, the air volume
involved and the working pressure. In fact if the piping is too small in diameter or of
excessive length, there is a risk of blocking the air flow, with a loss in charge and
reduced tool performance. Never use worn, damaged or faulty hoses.
13.The hosing used to convey the compressed air from the machine to the tool, or to
any other appliance that may be applied, must have a cock at one end of the hose
connection, this cock should be kept closed when connecting the hosing to the tool
and the machine in order to prevent the risk of accidental opening of the cock itself
with the consequent risk of severe wobbling of the hosing itself, and even a risk of

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personal injury. Before disconnecting any piping, always make sure that there is no
internal pressure.
14.Never fill up with fuel with compressor in action. Keep the fuel away from hot parts.
Never smoke during fuel filling operations. Never spread or leave any oil, fuel,
coolant liquids or detergent substances on the compressor or near it.
15.Never operate the compressor at speeds or pressure that is either above or below
the specified limits as indicated in the paragraph entitled “technical data”.
16.In the case of engines with closed circuit water cooling feature, allow the unit to
cool down before opening the filler cap.
17.Protect the ears using suitable ear-muffs, when noise output exceeds 85 dB (A).
Avoid exposure to these noise levels for extended periods of time.
SAFETY DURING MAINTENANCE AND REPAIR OPERATIONS
Maintenance and repair operations are to be undertaken solely by adequately trained
staff, supervised by a specifically trained technician in the field if necessary.
1. Use only the tools specifically suited to maintenance and repair operations.
2. Use only original spares.
3. All the standard maintenance operations aside from those of normal surveillance,
are to be undertaken only when the compressor it at a standstill. Concrete
precautions should be taken to ensure that the unit cannot be started up
accidentally.
4. Before dismantling any component under pressure, isolate the unit in an
appropriate manner against all pressure sources and discharge the pressure from
the entire system.
5. Never undertake any welding operations or other operations that generate heat
near any oil or fuel systems. The fuel and oils tanks in particular must be totally
clean before undertaking such operations, by steam cleaning them for example.
6. Always ensure that no parts, cloths or tools have been left inside or on top of the
unit.
7. Do not remove or tamper with the sound-proofing material.
ACCIDENT PREVENTION
Fixed protections are present on all the parts that either rotate or alternate and which
could be a potential personal hazard. The machine must not be operated once these
protections have been removed or before they have been replaced.
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-- 5) TECHNICAL DESCRIPTION --
This unit, like the entire MDVN range is an oil injection screw mobile motorized
compressor, single-stage and silenced.
The motor is of internal combustion type, and runs on gas oil, and transmits
power to the compressor by means of an elastic joint positioned co-axially between the
two.
-- 5.1) CHASSIS AND AXLE --
The chassis is made from contoured and electrowelded metal sheet and is of
load-bearing type. This chassis undergoes two painting treatments which guarantee
corrosion resistance and rust-proofing.
In the chassis there is the control panel which is protected by a transparent
polycarbonate lid and which allows the compressed air pressure and the compressor oil
temperature values to be read and allows a visual control of the warning lights each of
which will indicate any anomalies of the machine element to which it is connected.
A sprung axle of large dimensions supports the machine weight. It also has a
drawbar which can be fitted with hook and eyelet or sphere type. It consists of articulated,
elements which permit correct attachment to the various pulling means.
To tow the motor-driven compressor on the road it must be of homologated
version fitted for towing complete with lighting system, headlights and licence plate,
braking system and relative authorization from the "Motorization" department.
The braking system includes the parking brake and the inertia braking system.
Both act on the wheel-carrier drums of the axle.
-- 5.2) BODY --
The body is built entirely out of galvanized sheet iron. It can easily be turned
over thanks to a gas hoist and thus allows convenient access to the main machine
elements. The whole machine is entirely lined with sound absorbent and fire-retardant
material.
Special holes have been created in the elements forming the body, complete
with baffles, which allow the cool air necessary for engine and compressor cooling to be
sucked in from one side and the heated air to be expelled from the other side. These
baffles have been carefully designed in terms of size and shape so as to allow the most
efficient internal ventilation of the machine: it is advisable, therefore, to make sure that
these openings are kept free and undamaged.
All the parts of the body have been treated with a special painting process which
guarantees excellent finishing quality together with maximum impact and rust resistance.

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-- 5.3) MOTOR --
The unit is equipped with a Diesel motor, the features of which are described in
paragraph 2 (Technical data).
Consult the use and maintenance instructions and the manual supplied by the
manufacturing company and enclosed with this documentation.
-- 5.4) COMPRESSION UNIT --
It is completely manufactured in the ROTAIR factory and consists of a central
body (cylinder) inside which are fitted two screw rotors with asymmetric section, a male
one with 5 lobes and female one with 6 lobes.
The cylinder is closed at the ends by two head sections which contain the
bearings which bear the radial and axial loads created by the air compression.
A series of channels, inside the cylinder and heads, undertake to deliver the oil
to the various components. The distribution of the lubricant , serves to lubricate the
bearings and to maintain a coating of oil between the rotors and the bearings themselves
as well as the internal cylinder walls, thereby promoting compression resistance. Another
important function of the oil injected between the rotors is that of absorbing the heat
generated by the air compression.
The compressed air supplied by this compressor is free of any pulsations and
compression comes about axially.
A "regulator" unit is mounted on the compression unit, the purpose of which is
to regulate the quantity of air taken in according to the amount of air consumed. A double-
stage filter mounted on the top of this unit guarantees maximum purity of the suctioned
air.
-- 5.5) OIL SEPARATOR TANK --
Consists of a pressurized container, and due to its construction features it is
exempt from the annual I.S.P.E.L. inspection and is supplied with a conformity certificate
issued by the manufacturer. The identification and inspection details are impressed on a
plate which is welded to the machine.
The lid features the following elements: safety valve for overpressure, a thermal
switch which intervenes if the temperature inside the tank exceeds 100C and valves
which regulate the maximum and minimum pressure of the machine.
-- 5.6) BELL AND FLEXIBLE COUPLING --
The engine and the compressor are interconnected by a bell which
guarantees concentricity between the engine flywheel and the compressor shaft.
A large-size block joint with rubber pieces interspaced transmits power in a
smooth and silent way without splitting.
The engine-compressor thus assembled is clamped to the frame with four
flexible supports (silent-blocks) which completely absorb the vibrations it generates. A fan
is splined to the engine shaft on the opposite side to the flywheel which generates large
air displacement which cools the machine fluids and elements.

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-- 5.7) CONTROL INSTRUMENTATION AND DEVICES (FIG.1 --
The control panel layout, near the air exit cocks was specifically designed so as
to have all the controls within reach of a single person.
All the necessary instruments to control the unit are located on the control
panel.
Figure 1shows and identifies the various control and command devices.
INSTRUMENT
DESCRIPTION
1) Manometer
2) Hour meter
3) Start push-button
4) OFF/ON key
Fig. 1
1
3
4
2
Glow plugs preheating
warning light
Engine oil pressure
warning light
Alternator
warning light
Fuel level
warning light
Air filter obstruction
warning light
High temperature
warning light

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-- 5.8 WIRING SISTEM AND ITS FUNCTION --
This motor-driven compressor is fitted with a 12V wiring system with continuos current: the
wiring diagram is as follow (table 1):
Table 1
Details wiring diagram
1a
Starter motor
4b
Low pressure stop bulb (3,5bar)
7c
Mass
1b
ignition
4c
Fuel solenoid (hold)
8a
Spark plugs
1c
Magnet feed
5a
Temperature alarm
8b
Spark plug feed
2a
Feed
5b
Temperature alarm
8c
Fuel solenoid (pull)
2b
Mass
5c
Temperature alarm
2c
Solenoid feed
6a
Motor oil pressure (NC)
3a
Alternator
6b
Minimum pressure bulb (1,5bar)
3b
Discharge solenoid
6c
Air filter clogging sensor
3c
3-way solenoid
7a
Mass
4a
Low pressure stop bulb
(3,5bar)
7b
Gas oil tank float
The dimensions of all the electrical system components have been designed specially by
the manufacturing company; The system on the machine is protected with sheathing of
suitable electrical and mechanical characteristics and with high resistance to chemical
agents. Automotive fuses of adequate capacity are used to protect against overloading.

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CAUTION: All operations on the wiring system must be carried out by specialized
personnel.
1) WIRING SYSTEM FUNCTION
1.1) By turning the starting block key (part. 4 fig. 1) to the right in the position “ON”, the
panel is powered and the following warning lights come on:
Engine oil pressure warning light
This indicates whether the engine oil circuit is in pressure (warning light off) or not
(warning light on).
Alternator warning light
This indicates alternator efficiency.
Glow plug warning light
The first two warning lights are red and when the engine has been started they must be
off.
The glow plug warning light stays on for as long as it takes to heat the glow plugs after
which it switches itself off automatically. At this point it is possible to start the engine-
compressor by the push button (part 3 fig 1).
1.2) The starter motor is powered by the push-button which will start the diesel engine.
ATTENTION: as soon as the diesel engine has started, release the push-button
immediately.
2) By turning the starting block key (4) to the left in the "OFF" position the pressure in the
tank lowers up to 3-3,5bar.
As soon as the pressure reaches 3-3,5bar the engine automatically stops.

17
2) In machines approved for road use the electrical system is completed by lighting
wiring (TABLE 2). In the table, the wire connections inside the 7-pole socket are
given and their connection to the rear light apparatus. This system is connected
directly to the towing machine via an extension lead which is supplied with the
engine-compressor.
ATTENTION: Always ensure that the electrical system of the towing machine is
compatible with the engine-compressor light system (12V d.c.).
Table 2

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-- 5.8.1) SAFETY DEVICES --
These devices protect the machine from all malfunctions which could cause serious
damage to the machine, if they are not promptly eliminated.
6b Minimum oil pressure gauge: This device prevents the starting up if the machine
until the pressure inside the oil separator tank has not fallen to under 1.5 Bar. This
device consists of a pressure gauge which cutting off power to the starter motor.
6a Motor oil pressure gauge: N.C Contact device, which intervenes in the event of
insufficient pressure in the motor oil circuit. It de-energizes the gas oil solenoid valve
and discharge solenoid valve causing the motor to come to an immediate stop. The
engine oil pressure warning light comes on, indicating the anomaly.
5a Oil separator tank thermal contact: N.O. contact device which protects the oil
separator tank from temperatures of over 100C. This de-energizes the solenoid valves
immediately stopping the motor. The high temperature warning light comes on
indicating the anomaly.
5b Thermocontact on compressor: N.O. contact device, which intervenes in the event
of the overheating of the interior of the compressor which de-energizes solenoid valves
immediately stopping the motor. High temperature warning light comes on indicating the
anomaly.
5c Thermocontact on motor head: N.O. contact device which intervenes in the event
of motor over-heating. This de-energize solenoid valves which immediately stops the
motor. The high temperature warning light comes on indicating the anomaly.
F1 Spark plug fuse: Protective device against anomaly currents which could
damage the motor glow plugs during glow plug pre-heating. The capacity of this fuse is
of 40A.
F2 Secondary fuse: Protective device against anomaly current which may
damage components such as the solenoid valves, relays, hourmeters, etc. This fuse
has a capacity of 16A..

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-5.9) OLEOPNEUMATIC PLANT (Fig. 3) --
-- 5-9-1) COMPRESSOR LUBRICATION SYSTEM --
The system includes the oil separator tank (Z), the thermostatic valve (U) on
which, at the entrance, the oil filter (V) and the oil cooling radiator (M) are mounted.
As shown in fig. 4 the lower part of the oil separator tank (Z) acts as an oil tank,
will the filtering part is situated at the top which separates the air from the oil.
On starting up the machine, the pressure generated by the compressor, makes
the oil inside the tank flow through the conduit in the direction indicated by the arrow. A
thermostatic valve (U) is positioned along the route, which according to the actual oil
temperature, conveys it all or partially to the cooling radiator (M), more specifically:
- at temperatures of below 65c, the thermostatic valve remains open and the
oil in circulation is directly injected into the compressor, without going through the radiator
(M).
FIG. 3
During the working cycle the oil is heated and when it reaches a temperature of
65C, the thermostatic valve (U) begins to close, thereby making it necessary for part of
the oil to go through the cooling radiator (M).

20
When the oil temperature reaches 75C, the thermostatic valve (U9 closed
completely and from then on all the oil in circulation goes through the radiator and is
thereby cooled (M).
From the radiator (M) the oil is injected into the compressor (O).
The filter (V) has an internal "by-pass" valve which permits oil circulation even if
it gets blocked. In which case the oil will circulate regularly without being filtered. It is
therefore necessary to replace the filter at regular intervals, as indicated in the
maintenance programme.
The cooled and filtered oil thereby reaches the compressor (O) and by means
of the various internal channels it is distributed to the various parts (rotors, bearings etc)
which are thereby cooled and lubricated. From the compressor (o), the oil mixed with
compressed air is sent to the tank (Z), inside which the separator (Y) undertakes to
separate it from the air.
We have mentioned that the separator filter (Y) provides to separate the air
from the oil; however a very small quantity is still able to penetrate the inside of the filter,
and deposits itself on the low and concave part of the same. It is sucked through the
piping on which the calibrated nozzle and the single-direction valve are positioned. The
latter impedes the return of oil into the oil separator filter when the machine is stopped.
-- 5-9-2) PNEUMATIC SYSTEM (Fig. 3) --
The system includes: the suction filter (A), the suction regulator (B), compressor
(O), tank (Z) and the oil separator element (Y), the minimum pressure and non-return
valve (L), the cock (R) and the maximum pressure valve (G), and the discharge solenoid
valve (P).
The suctioned air, after having passed through the double stage filter (A)
reaches the suction regulator, followed by the compressor which conveys it, together with
the injected oil, into the oil separator tank. Where the air is separated from the oil. This
separation process firstly comes about by means of centrifugal spinning and in the second
stage with the use of the oil separator filter (Y).
The air which is cleansed of the oil, is conveyed by the minimum pressure valve
(l), and only opens when the pressure in the tank reaches the pre-set value. This minimum
pressure formed in the tank guarantees oil circulation even when the air discharge taps
(R) are in fully open position.
It is however a good idea not to use tools and equipment, which excessively
consume compressed air, and which may cause the tank pressure to fall to below 5-5.1
bar.
In fact prolonged working conditions at below 5 bar, may cause compressor
overheating, due to insufficient lubrication, and inadequate air and oil separation, resulting
in excessive lubricant consumption.
The solenoid valve (P), on stopping the machine, opens automatically, gently
discharging all the compressed air still inside the system into the atmosphere.
The minimum pressure valve (L) also acts as a single-direction valve,
impeding return into the compressed air unit of air coming from channels or tools
connected to the machine.