S.C. KOYO ROMANIA S.A.

ALEXANDRIATELEORMAN

27.10.2005

NOISE EXPOSURE REDUCING NOISE EXPOSURE REDUCING DOMAINDOMAIN

ACTIVITY : FORGING ON ACTIVITY : FORGING ON AUTOMATIC FORGING PRESS AUTOMATIC FORGING PRESS

FOR BEARING RINGSFOR BEARING RINGS

HEATING OF STEEL BARS IS MADE HEATING OF STEEL BARS IS MADE BY INDUCTION USING HIGH BY INDUCTION USING HIGH

FREQUENCY CURRENTSFREQUENCY CURRENTS

PRODUCTION CAPACITYPRODUCTION CAPACITY : :• 2 automatic forging lines, AMP 50 type2 automatic forging lines, AMP 50 type• 4 automatic forging lines, AMP 30 type4 automatic forging lines, AMP 30 type• 1 automatic forging lines, AMP 20 type1 automatic forging lines, AMP 20 type

An automatic forging line consisted of : heating installation by induction with high frequency currents, using rotary converters and automatic forging press.

Steel bars to heat are between 20 mm and 50 mm diameter and the heating temperature is 1150 grd.Celsius. Steel bars are forging on automatic press and the results are cylindrical pieces (bearing rings) in one piece or tower with rings separation.

IN THE PAST

The heating installation with high frequency currents has 2, 3 or 12 rotary converters, depending on steel bars diameter to heat and press type, AMP 20 / 30 / 50.

Rotary converters were located on the basement for 3 forging press, who were set to work in 1973 – 1974, or on the section floor for other 4 forging press who were set to work in 1985 – 1989.

ROTARY CONVERTERS PRESERVED

During the rotary converter works, there is a strong continuous and constant noise, generate by : Driver working – engine output = 320 kW

and speed 3000 rotations per minute Generator working – generator output = 280

kW and frequency = 2500 Hz; Ventilation and cooling system working.

According to measurements, in working area was between 108 – 110 dB (A)

Reliability : because of its mechanical construction, with moving elements, there were depreciations of this elements, mechanical blockings, electrical failings – the result was big stop times.

Electrical consumption was very high because : Low power efficiency of the rotary converter as an

electrical machine (90%) Empty running consumption during the press

adjustment. Big installed capacity (3.8 MW – AMP 50)

NOW

Steel bars heating is make using heating installations by induction with high frequency currents , with static converters.

STATIC CONVERTERS

AUTOMATIC FORGING PRESS

ADVANTAGES ADVANTAGES Electrical construction only, no moving Electrical construction only, no moving

elements;elements; Each heating installation use only one Each heating installation use only one

frequency converter;frequency converter; Big reliability – Because of electrical Big reliability – Because of electrical

construction, there are only electrical construction, there are only electrical failings so the stop times are small;failings so the stop times are small;

Lower electrical consumption – because Lower electrical consumption – because of good power efficiency (98%), quick of good power efficiency (98%), quick start and stop, without conditions, low start and stop, without conditions, low installed capacity (2.2 MW – APM 50)installed capacity (2.2 MW – APM 50)

NOISE LEVEL IN WORKING NOISE LEVEL IN WORKING AREA DECREASED AREA DECREASED

TO 90 Db (A)TO 90 Db (A)