MBM PP 35 Manuel D'instructions Et D'entretien page 5

NOISE
Noise is generated during the cutting process. The noise level depends on the cutting parameters used.
BURNS
The operator should be adequately protected during cutting operations. This should be routine practice.
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.
GENERAL INFORMATION
PLASMA ARC AND BASIC PRINCIPLES FOR THE PERFORMANCE OF PLASMA CUTTING
√ √ √ √ √
Plasma is a gas that is heated to an extremely high temperature and ionised so that it becomes a
conductor of electricity.
√ √ √ √ √
This cutting procedure utilises the plasma to transfer the electric arc to the metal workpiece, which
is melted by the heatand then separated.
√ √ √ √ √
The torch uses compressed air from a single source, for both the plasma and cooling and protective
gas.
√ √ √ √ √
The start of the cycle is determided by an arc, called the pilot arc, which is struck between the mobile
electode(negative polarity) and the torch nozzle (positive polarity) due to the short circuit between
these two elements.
√ √ √ √ √
When the torch is brought into direct contact with the workpiece to be cut (connected to the positive
polarity of the power source) the pilot arc is transfered between the electrode and the workpiece
itself thus striking a plasma arc, also called cutting arc.
√ √ √ √ √
The duration of the pilot arc is set in the factory at 4 seconds; if the transfer has not been made within
this time, the cycle is automatically stopped except for the cooling air which is kept on.
Noise can damage hearing
Wear adequate hearing protection.
Do not point the torch jet at people or foreign bodies.
CAUTION!
CAUTION!
5