Atlas Copco LF75 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 LF75 Specifications

General

Brand	Atlas Copco
Model	LF75
Category	Air Compressor
Language	English

Summary

Installation and Handling

Installation Proposals

LE/LF/LT Installation

Electrical Connections

Details requirements for electrical installation, mains supply, and earthing.

Settings of Overload Relay, Fuses, and Cable Size

Provides settings for overload relays and fuses for DOL starter compressors.

Settings of Overload Relay and Fuses for DOL Starter Compressors

Details overload relay and fuse settings for DOL starter models at 50 Hz and 60 Hz.

Settings of Overload Relay and Fuses for Y-D Starter Compressors

Details overload relay and fuse settings for Y-D starter models at 50 Hz and 60 Hz.

Cable Size

Operating Instructions

Initial Start-Up

Provides initial start-up steps and recommendations for compressors.

Starting

Details the starting procedure for LE/LF/LT and Trolley models.

Stopping

Explains how to stop LE/LF/LT compressors and Trolley units.

Maintenance

Preventive Maintenance Schedule for the Compressor

Summarizes maintenance tasks and intervals for the compressor.

Lubrication of LE/LT Compressors

Servicing and Adjustment Procedures

Unloader or Check Valve

Valves

Adjustment MDR4 Pressure Switch

Details how to adjust the maximum and pressure difference settings of the MDR4 switch.

Adjustment MDR5/6 Pressure Switch

Explains how to adjust the MDR5/6 pressure switch settings for stopping and starting pressure.

Adjustment Pilot Valve on Trolley

Details how to adjust the pilot valve for maximum pressure and unloading on Trolley units.

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

Guides on testing and replacing the safety valve if it doesn't open correctly.

Relief Valve on LF55/75, LE75 up to -150 and LT

Problem Solving

Insufficient Air Pressure

Lists potential causes and solutions for insufficient air pressure.

Unit Does Not Speed Up

Air Receiver Pressure Rises Above Maximum and Causes Safety Valve to Blow

Addresses issues where receiver pressure exceeds maximum, causing safety valve activation.

Relief Valve Blows

Receiver Does Not Hold Pressure

Guides on diagnosing and fixing issues related to the air receiver losing pressure.

Too Frequent Starting/Too Short Operating Periods

Explains common causes for excessive compressor cycling and short run times.

High Oil Consumption on LE/LT Compressors

Unit Does Not Start

Provides troubleshooting steps for when the compressor unit fails to start.

Overload Relay Cuts Out

Explains causes and solutions for the overload relay tripping.