SIEMENS
Engineering information
SINAMICS GM150, SINAMICS SM150
Cooling unit
9/8
Siemens D 12 · 2012
9
■
Overview
The cooling unit is used to dissipate the power loss from the con-
verter. It consists of an inner fresh water circuit and an outer raw
water circuit.
■
Mode of operation
The heated fresh water in the inner circuit of the converter
passes through two redundant, maintenance-free circulation
pumps into the water/water plate heat exchanger which is made
of high-grade steel and connected to the untreated water circuit
on the installation side. The fresh water is cooled by the un-
treated water of the outer circuit and flows back into the con-
verter.
The closed inner fresh water circuit is filled with deionized water
and vented by means of a compensating tank. This tank is
situated at the highest point of the cooling circuit.
■
Function
Raw water specifications
The raw water must be chemically neutral, clean and free of
solids. Other quality requirements to be met by the raw water are
listed in the following table.
In case of deviations it is recommended to carry out an analysis
of the water in order to ensure the heat exchanger's endurance
strength. In case of aggressive cooling water (including sea
water), plate-type heat exchangers made of titanium should be
used (options
W11
and
W12
).
Avoiding condensation
To avoid condensation at excessively low raw water tempera-
tures, a three-way valve for controlling the water temperature is
installed as standard.
Specifications for the cooling water in the fresh water circuit
Clean water (battery water) should be used to fill and top-up the
deionized water circuit
Monitoring units in the fresh water circuit
To guarantee the self-protection of the converter, the deionized
water is monitored by the converter:
•
Conductivity measurement:
The conductivity of the cooling water is constantly monitored
in order to ensure that the leakage currents in the converter
between different potentials and against ground remain small.
An ion exchanger (in the cooling unit) holds the conductivity
below the permitted maximum value of 1.0
µ
S/cm. If the
conductivity is too high, the ion exchanger filling must be
changed. After the first year, an ion exchanger filling must
be changed at least every two years as a rule.
•
Temperature monitoring
•
Flow monitoring
•
Leakage water monitoring
Other monitoring operations and the control of the electrical
equipment are performed in the cooling unit:
•
A compensating tank for the compensation of changes in the
volume of cooling water due to evaporation or temperature
changes
•
Indication of pressure in the converter inlet
The operating status is signaled to the converter.
Piping
The cooling unit consists of one transport unit and is supplied
without deionized water.
For SINAMICS GM150 in the IGBT version and
SINAMICS SM150 in the IGBT version, a pipe-connecting
element between the cooling unit and converter is included in
the scope of delivery. As standard, the water connections are
located on the side.
For SINAMICS GM150 in the IGCT version and
SINAMICS SM150 in the IGCT version, the piping between the
cooling unit and the basic unit is realized below the units
(refer
to example shown in following diagram)
. The necessary pipes
and connection pieces are included in the scope of delivery and
are supplied loose. Rigid pipes are used (stainless steel). The
converter is connected to the stainless steel pipe using a flexible
hose. The height of the vertical pipes can be adjusted.
Special installation conditions have not been taken into account
and, where applicable, a separate inquiry is necessary (e.g. where
the cooling unit is not mounted directly next to the basic unit).
The piping for the raw water supply on the plant side is not
included.
Piping for SINAMICS GM150 in the IGCT version and for
SINAMICS SM150 in IGCT version
Raw water
Grain size of any entrained parts
< 0.5 mm
pH value
6.5 ... 8.0
Carbonate hardness
< 0.9 mMol/l (5 °dH)
Total hardness
< 1.7 mMol/l (9.5 °dH)
Chlorides
60 mg/l
Sulfates
80 mg/l
Nitrates
10 mg/l
Iron (Fe)
0.2 mg/l
Ammoniac
10 mg/l
Dissolved substances
< 3.4 mMol/l (340 ppm)
Deionized water
In accordance with
DIN EN 60993 (IEC 60993)
Specific conductivity when filled in
≤
30
µ
S/cm
1)
Evaporation residue
< 20 mg/l
pH value
5 ... 9
Content of
• metals from the hydrogen sulfide group
(lead, antimony, tin, bismuth, arsenic,
copper, cadmium)
• metals from the ammonium sulfide
group (iron, cobalt, nickel, chrome,
manganese)
• sulfur and nitrogen chloride compounds
Not detectable
Content of oxidizable, organic sub-
stances
Max. a quantity equivalent
to the usage of 30 mg/l
potassium permanganate
KMnO4
Cooling unit
Converter
Piping
G_D012_EN_00045
1)
After the converter is filled and before the converter is switched on,
the conductivity value is reduced to the permitted operating value of
< 1.0
µ
S/cm by the ion exchanger which is integrated in the cooling unit.
© Siemens AG 2012