Danfoss BOCK HRX CO2 T H Translation Of The Original Instructions page 9

3 | Areas of application
Minimal rotational speed n
Maximal rotational speed n
Rotational speed range
Start-up time
Switch-off time
© Danfoss | Climate Solutions | 2023.06
- Operation up to 75 Hz for the HRX40 and 65 Hz for the HRX60 and
400V is possible in "field weakening". This starts where the fre-
quency converter output voltage cannot be increased further, but
the frequency continues to rise. The frequency converter must be
dimensioned for the max. operating current at 400V - 75 Hz (HRX40)
resp. 65 Hz (HRX60), see Technical Data page 22.
- A minimum running time of 2 minutes steady-state condition
(continuous operation) must be achieved.
- Minimum downtime in frequency-controlled operation 1 minute.
- If the frequency converter already has a motor heating option,
it must be used. If this option is not available, but the frequency
converter has the option to define vertices of the U/f characteri-
stic, these must be set as follows:
• Select the first vertex and set it to 18 V and 0 Hz. Select this vertex
as a fixed frequency and activate it. (This creates a DC current of
approximately 18 V on the motor winding and creates a current
flow through which the stator and the oil heat up).
• Note: The motor PTCs must be monitored in order to interrupt
the process if the motor winding heats up too much!
• It takes 15 to 30 minutes to heat up the oil without the motor
winding becoming too hot.
= 12,5 Hz
min
= HRX40=75 Hz, HRX60=65 Hz
max
12,5 Hz - 75 Hz HRX40
0 - 12,5 Hz
12,5 Hz- 65 Hz HRX60
< 1 s
instantaneously
4 s
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