Clarke 20CI, Operation & Maintenance Instructions Manual

7

EMC

Before installing the plasma cutting unit, carry out an inspection of the 
surrounding area, observing the following guidelines:

1. Make sure that there are no other power supply cables, control lines, 

telephone leads or other equipment near the unit.

2. Make sure that there are no radio receivers or television appliances.

3. Make sure there are no computers or other control systems.

4. Make sure that there is no-one with a pacemaker or hearing aid in the 

area around the unit.

5. Check the immunity of any other equipment operating in the same 

environment. In certain cases additional protective measures may be 
required.

Interference can be reduced in the following ways:

1. If there is interference in the power supply line, an E.M.C. filter should be 

inserted between the mains and the unit.

2. The output cables of the unit should be shortened; these should be kept 

close together and stretched along the ground.

3. All the panels of the unit should be correctly closed after carrying out 

maintenance.

SAFETY DEVICES

The plasma cutting units are supplied with the following safety devices:

THERMAL PROTECTION DEVICES 

These are installed at the points most subject to high temperatures such as the 
power transformers and the rectifying units. An amber light on the front panel 
lights up when the thermal protection device intervenes.

AN ELECTRIC SHOCK PROTECTION DEVICE 

This prevents the operator from coming into contact with the live parts of the 
torch (such as the electrode, etc.) This consists of a safety device, built into the 
body of the torch, which breaks the main power circuit when the end part of 
the torch is removed to replace the electrode or the tip.

When the electrical protection device intervenes, the unit is prevented from 
operating.