Equipotential Bonding - Siemens SINAMICS S120 Equipment Manual

Cooling circuit and coolant properties
8.1 Cooling circuits
Recommendation for dimensioning the cooling circuit:
The differential pressure between the supply and return lines should be selected such that
the following applies:
∑
dPi
The individual pressure drops Pi represent the pressure drops of components (heat
exchanger, piping, 70 kPa for the SINAMICS units connected in parallel, valves, dirt traps,
pipe bends, etc.).
The greatest care must be taken when routing pipes. The pipes must never come into
contact with electrically live components; an insulation clearance of >13 mm must always be
left between pipes and live parts! The pipes must be securely mounted and checked for
leaks.
8.1.5

Equipotential bonding

All components in the cooling system (SINAMICS units, heat exchanger, piping system,
pump, pressure compensator, etc.) must be connected to an equipotential bonding system.
A copper bar or stranded copper with the appropriate conductor cross-sections must be used
for this purpose to eliminate electrochemical processes.
If the installation comprises several control cabinets, these must be bolted together in a
solid, conductive connection (e.g. bolt cabinet cross-beams together directly at several
points to make conductive connection). This eliminates potential differences and thus the risk
of electrochemical corrosion. A PE bar must be installed in every cabinet (including the
recooling system) and the individual bars then interconnected.
8-12
∑
< < +
dP dPi 0.3 bar
Syst
SINAMICS S120 Equipment Manual, Edition 12/2007, 6SL3097-2AM00-0BP4
Chassis Power Units Liquid Cooled