Cooling Water Requirements - Atlas Copco GA 37+ Instruction Book

Re fe re nce
7
Instructions
1. Provide an isolating switch.
2. Check that the motor cables and wires inside the electric cabinet are clamped tight to their terminals.
3. Check the fuses and the setting of the overload relay. See section
4. If terminals 1, 3 and 5 of motor contactors K21 and K23 are not bridged, connect power supply cables to
terminals 1, 3 and 5 of contactor K21 and to terminals 1, 3 and 5 of contactor K23.
If terminals 1, 3 and 5 of motor contactors K21 and K23 are bridged, connect power supply cables to
terminals L1, L2 and L3 of terminal strip 1X0.
The power cables must be connected stress-free to the terminals to avoid mechanical forces to the
terminals. For this reason, the use of flexible cables is strongly advised.
Also see section
5. Connect earth conductor bolt (PE).
6.4

Cooling water requirements

General
The cooling water quality must meet certain minimum requirements. No general recommendation can
encompass the effects of all combinations of the various compounds, solids and gases typically found in cooling
water in interaction with different materials. This recommendation is a general guide line for acceptable
coolant quality.
It is very important to make a distinction between a closed system or an open system. In a closed system, the same
cooling water is circulating through a system without contact with air. An open system is a pass through system, or
a circulating system with a cooling tower. In the latter case, one has to consider the composition of the water as it
enters the cooler, and not rely on the composition of the make-up water. Due to the evaporative effect in the
cooling tower, much higher concentrations of ions can be obtained in the circulating water than in the make-up
water.
Cooling water parameters
1. The Rysnar stability index (RSI)
The Rysnar Index (RSI) is a parameter for predicting whether water will tend to dissolve or precipitate
calcium carbonate. The adhesion of scaling depositions and their effect are different on different materials,
but the equilibrium of the water (scaling or corrosive) is only determined by its actual pH value and by
the saturation pH value (pHs). The saturation pH value is determined by the relationship between the
calcium hardness, the total alkalinity, the total solids concentration and the temperature. The Rysnar
Index is calculated as follows: RSI = 2*pH
•
pH = measured pH (at room temp) of water sample
•
pH = pH at saturation
s
pH is calculated from:
s
pH = (9.3 + A + B) - (C + D),
s
in which
•
A : depends on the total solids concentration (mg/l).
100
De s ignation
Delta connection: 200/220/230 V - 50/60 Hz
Electric cable size.
- pH, in which
s
Instruction book
Settings of overload relay and fuses.
9096 3321 00