1.4 Wiring
All electrical hook up should be done by a certified electrician,
in conformity with local electrical codes.
Be sure that:
1.
The supply line has the same electrical characteristics
(voltage, phase and cycle) as the motor. (Check table
2 for recommended wire size).
2.
The electric meter is large enough and service is of
adequate ampere rating.
3.
The line wire is the proper size and that no other
equipment is operated from the same line. Improper
wire size will cause excessive motor loads and
possible motor burn-outs.
All Directair 3-phase units require a magnetic starter, as do 5
HP and up 1-phase applications.
Never operate the unit without a ground connection.
1.4.1 Table 2: Recommended wire size
Max. length Time-delay
Motor HP/phase Voltage Wire size of line (ft) 1)
fuse size
2/1
208
12
75
25
2/1
230
12
75
25
3/1
208
10
75
30
3/1
230
10
75
30
5/1
208
6
100
50
5/1
230
6
100
50
5/1
460
12
100
25
2/3
208
14
75
20
2/3
230
14
75
20
2/3
460
16
75
15
3/3
208
14
75
20
3/3
230
14
75
20
3/3
460
16
75
15
5/3
208
12
100
30
5/3
230
12
100
25
5/3
460
14
100
15
7.5/3
230
8
125
40
7.5/3
460
14
125
20
10/3
208
6
125
50
10/3
230
6
125
50
10/3
460
12
125
25
20/3
230
3
125
90
20/3
460
8
125
40
25/3
230
2
125
100
25/3
460
6
125
50
1) Use an aluminum or copper-clad aluminum wire.
In case of motor failure. return to local authorized motor
repair station
2 Initial start-up
1.
Check all wiring for loose connections. A loose wire
could cause a loss of power or a short circuit. Be
sure that the thermal overload relay in the starter is
properly set (if applicable) to provide adequate motor
overload protection.
2.
Check oil level in sight gauge It should be filled to the
middle of sight glass. If not, fill to the proper level.
Use only a detergent oil with a SAE number 10W, API
classification CD or SF, military specification MIL-L-
2104C or MILL-461 52, available at your Atlas Copco
distributor.
3.
Start the compressor and check the rotation of the
fan, which should blow air over the cylinder. Stop the
compressor immediately if the fan turns in the wrong
direction. If unit is 3-phase, interchange any two lines
If unit is single phase, see motor nameplate on motor.
4.
Check that pressure switch operates at the pressure
limits specified.
5.
Check all piping for leaks Repair if necessary.
6.
Your compressor is now ready for use.
5
