Parker NX Series, Техническое руководство, Страница: 81 / 116

81 - PVD 3663_GB_NX_March 2017.Docx
3.6.5. Motor cooling circuit drop pressure
The tab below describes the drop pressure at the water flow rate from the motor data:
Motor type Drop pressure @ nominal water flow
NX860W 0.3 bar @ 5 l/min
Note : all motors drop pressure are checked before shipping.
3.6.6. Chiller selection
This section describes how to choose the chiller. The chiller is able to evacuate the
heat from the motor losses with the water circulation.
The motor losses (= power to evacuate by the chiller) depend on the efficiency and
motor power:
.Pn 1
ρ
1
Pc






 
With Pc : Power to evacuate by the chiller (kW)
Pn : Nominal motor power (kW)

: motor efficiency at nominal power (%)
Refer to the respective motor data sheet for nominal power, efficiency and water flow.
Chiller pump must provide water flow through motor and pipe pressure drop.
Inlet temperature must be inferior to
25°C .
Example
Motor : NX860W
For a torque of 80 N.m @ 2500 rpm, the efficiency is 92%.
Water flow = 5 l/min
Pn = 80 x 2500 x

/30
Pn = 20.9 kW
.20.9 1
0.92
1
Pc






 
= 1.8 kW
So, the chiller must evacuate 1.8 kW and has a water flow of 5 l/min for this point of
running.