Makita AB series, Instruction Manual And Safety Instructions

GB

20 

ELECTRICAL CONNECTION 

Single-phase compressors 

are supplied with an electrical cable and a 

two-pole + earth plug. The compressor 

must

 be connected to a grounded 

power socket (fig.12). 

Three-phase  compressors

 (L1+L2+L3+PE) must be installed by a 

specialised technician. Three-phase compressors are supplied without 
a plug. Connect a plug, with screw-on grommet and securing collar 
(fig.13), to the cable, consulting the table below. 

HP 

kW 

Power supply volt/ph Plug model 

2 – 3 – 4 

1.5 – 2.2 – 3

220/380/3 
230/400/3  16A 3 pole + ground 

5.5 – 7.5 – 10 4 – 5.5 – 7.5 

220/380/3 
230/400/3  32A 3 pole + ground 

NOTE: 

Compressors installed on the 500 lt tank, with capacity of HP7.5/

55 kW and HP10/7.5 kW can be supplied a star/triangle starting control
unit, whereas the TANDEM (n. 2 pumping elements on the same tank)
are supplied with a timed control unit for staggered starting of the two
pumping elements.
Installation instructions:
– Secure the control unit box on a wall or on a fixed support, and provide 

it with a power cable with plug, of a diameter in proportion to its 
length. 

– Any damage caused by incorrect connections of the power line to 

the mains, automatically excludes warranty of electrical parts. To avoid 
connection errors, we advise you to contact a specialised technician. 

IMPORTANT: 

Never use the ground socket instead of the neutral wire. The ground 
connection must be made to meet safety standards(EN 60204). 
The plug of the power cable must not be used as a switch, but must be 
fitted in a power socket controlled by a suitable differential switch (thermal-
breaker). 

STARTING 

Check that the mains power matches that indicated  on the electrical 
data-plate (fig.14) – the permissible tolerance range  is +/-5%. When 
first starting compressors operating on 3-phase voltage, check the 
rotation direction of the cooling fan by comparing it with the direction of 
the arrow on the belt guard or on the protective housing. In the SILENT 
compressor, check if the air flows is in the direction illustrated in fig.21A. 
Turn or press into position “0” (according to the type of pressure switch 
fitted on the appliance) the knob located on the upper section (fig. 15). 
Fit the plug in the power socket (fig. 12 - 13) and start the compressor, 
turning the pressure switch knob into position “I”. The compressor is 
fully automatic, and is controlled by the pressure switch which stops it 
when tank pressure reaches maximum value and restarts it when it falls 
to minimum value. The pressure difference between maximum and 
minimum values is usually about 2 bar (29 psi). 
E.g.: the compressor stops when it reaches 8 bar (116 psi – maximum 
operating pressure) and restarts automatically when the pressure inside 
the tank drops to 6 bar (87 psi). 
After connecting the compressor to the power line, load it to maximum 
pressure and check exactly how the machine is operating. 

solenoid-valve indicator-light “D” and the motor (C) indicator-light (C) go 
on in that order, this means the machine is operating perfectly (fig. 18). 

TANDEM COMPRESSORS WITH TIMED 

CONTROL UNIT 

(fig. 17) 

Fit the plug in the power socket (fig. 13) and turn the pressure switch to 
position “I” (ON). Turn the master power switch “A” on the control unit to 
position I – power On is signalled by white indicator-light “E” going on. 
Turn switch “B” to start the compressor. 
Pos. 1 pumping element n. 1 only is operating 
Pos. 2 pumping element n. 2 only is operating 
Pos. 3 both pumping elements are operating simultaneously, at staggered 
starting times. 
The compressor is fully automatic, and is controlled by the pressure 
switch which stops it when tank pressure reaches maximum value and 
restarts it when it falls to minimum value. 

NOTE: 

The head/cylinder/delivery tube unit can reach 

high temperatures. Take care when working near these parts, and do 
not touch them to avoid possible burns (fig. 18 - 19). 

IMPORTANT 

The electro-compressors must be connected to a power socket protected 
by a suitable differential switch (thermal-breaker). The motor of GM-TR 
compressors is equipped with an automatic thermal breaker located 
inside the winding – this stops the compressor when motor temperature 
reaches excessively high values. 
If the breaker is tripped, the compressors 

restarts automatically

 after 

10 to 15 minutes. The motors of compressor models VX are supplied 
with a manually resetting automatic amperometric thermal-breaker, 
located outside the terminal board cover. 
When the breaker is tripped, wait for a few minutes and then reset the 
breaker manually (fig. 20). 
The motors of the AB series compressors are supplied with a manually 
resetting amperometric thermal-breaker, located on the terminal board 
cover. When the breaker is tripped, wait for a few minutes and then 
reset the breaker manually (fig. 20). 
The safety davice is automatic in three-phase and silent compressors. 
When the thermal-breaker is tripped, the pressure switch is released to 
“0” (OFF) position. 
Wait for a few minutes and return the pressure switch to “I” (ON) position 
(with the exception of models: AB 100/245-335 Three-phase - AB 150/ 
245-335 Three-phase - AB 200/245-335 Three-phase). For 
compressors supplied with a control unit, the thermal-breaker is installed 
inside the control unit. When the thermal-breaker is tripped, observe 
the following procedure (fig. 22): 
• Turn the switches on the control unit cover to position “0”, open the 

cover and press push-button 1 of the thermal-breaker. Close the 
cover of the control unit and restart the compressor, observing the 
operations described in the paragraph “Starting compressors with 
control unit”. 

The same instructions apply to compressors powered at 60 Hz. 

ADJUSTING OPERATING PRESSURE  

(fig. 23) 

You do not have to use the maximum operating pressure at all times. On 
the contrary, the pneumatic tool being used often requires less pressure. 
On compressors supplied with a pressure reducer, operating pressure 
must be correctly adjusted. 

COMPRESSORS WITH 

Y

D STARTING 

Release the pressure reducer knob by pulling it up, adjust pressure to 

CONTROL UNIT 

(fig. 16) 

the required value by turning the knob clockwise to increase pressure 

Fit the plug in the power socket (fig. 13) and turn the pressure switch to 

and anti-clockwise to reduce it. When you have obtained optimum 

position “I” (ON) (fig. 17). Turn the master power switch “A” on the control 

pressure, lock the knob by pressing it downward (fig. 23). For pressure 

unit to position I – power On is signalled by white indicator-light “E” 

reducers equipped without a pressure gauge, the set pressure can be 

going on. Turn switch “B” to position 1 to start the compressor. If the 

seen on the graduated scale located on the reducer body.