Danfoss VACON NX Commissioning And Maintenance Manual page 36

3 6 VACON
Figure 5.3-5 Example 2b
The secondary circuit maximum temperature should always be 5C lower than the primary circuit
temperature to ensure a good thermal load transfer between the two circuits. In example 2b this
means that the secondary circuit should be between +5...+25C during operation. The 3-way valve in
the secondary circuit will then keep the primary circuit temperature at 30C regardless of the main
drive load.
Exampl e 3, high secondar y cir cuit temper atur e
If the customer has an existing cooling system that delivers liquid at a temperature of 40C then the
primary circuit temperature has to be 5C warmer to maintain a sufficient heat transfer between the
primary and secondary circuit. This means that the primary circuit temperature cannot be colder
than 45C. This results in a significant reduction of the main drive load. In this case the only way of
increasing the load of the main drive is to lower the temperature in the secondary circuit by
installing additional coolers or a new cooling system with a lower water temperature. Next the dew
point must be checked.
Secondary circuit maximum temperature = 40C
Primary circuit maximum temperature = 40C (40C+5C)
Ambient temperature = 30C
Maximum relative humidity = 95%
Because the ambient temperature is beneath the primary circuit temperature there is no risk of
condensation in the main drive.
5
Maximum ambient temperature +40°C
Maximum ambient relative humidity 50%
VACON LIQUID COOLED NX DRIVE
Primary circuit minimum +30°C (28°C+2°C)
Local contacts: http:/ / dr ives.danfoss.com/ danfoss- dr ives/ local - contacts/
COMMI SSI ONI NG
HXL120
Secondary circuit
maximum +25°C
(30°C-5°C)