Atlas Copco LT75 User Manual

Atlas Copco Stationary Air Compressors
*2920125704*
No. 2920 1257 04
Registration code: APC L / 38 / 989
Replaces 2920 1257 03
2000-10
LE/LT15, -22, -40, -55, -75, -110, -150
LF15, -22, -40, -55, -75
www.atlascopco.com
• Copyright 2000, Atlas Copco Airpower n.v., Antwerp, Belgium.
Any unauthorized use or copying of the contents or any part thereof is prohibited. This applies in
particular to trademarks, model denominations, part numbers and drawings.
• This instruction book meets the requirements for instructions specified by the machinery directive
98/37/EC and is valid for CE as well as non-CE labelled machines.
Instruction Book

Atlas Copco LT75 Specifications

General

Brand	Atlas Copco
Model	LT75
Category	Air Compressor
Language	English

Summary

Installation and handling

Installation proposals

Electrical connections

Outlines the procedures and requirements for connecting the compressor electrically.

Settings of overload relay - fuses - cable size

Specifies crucial settings for electrical protection and wiring.

Settings of overload relay - fuses of compressors with DOL starter

Provides overload relay and fuse settings for DOL starter compressors.

Settings of overload relay - fuses of compressors with Y-D starter

Provides overload relay and fuse settings for Y-D starter compressors.

Operating instructions

Initial start-up

Guides the user through the first-time setup and operation of the compressor.

Starting

Details the procedure for starting the compressor safely.

Stopping

Explains the correct method for stopping the compressor.

Maintenance

Preventive maintenance schedule for the compressor

Outlines a schedule of regular maintenance tasks for the compressor.

Lubrication of LE/LT compressors

Servicing and adjustment procedures

Unloader or check valve

Valves

Adjustment MDR4 pressure switch

Explains how to adjust the MDR4 pressure switch for setting operational pressures.

Adjustment MDR5/6 pressure switch

Explains how to adjust the MDR5/6 pressure switch for setting operational pressures.

Adjustment pilot valve on Trolley

Details the adjustment procedure for the pilot valve on trolley models.

Safety valve (SV-Figs. 1.4, 1.5 and 1.8)

Covers testing, replacement, and adjustment of the safety valve.

Relief valve (8-Fig. 1.1) on LF55/75, LE75 up to -150 and LT

Problem solving

Insufficient air pressure

Troubleshooting steps for low air pressure issues.

Unit does not speed up

Air receiver pressure rises above maximum and causes safety valve to blow

Troubleshooting high pressure and safety valve activation.

Receiver does not hold pressure

Too frequent starting/too short operating periods

Unit does not start

Overload relay cuts out