Motor Cooling Circuit Drop Pressure; Chiller Selection - Parker NK Series Technical Manual

3.5.4.

Motor cooling circuit drop pressure

The tab below describes the drop pressure at the water flow rate from the motor data:
Motor type
All NK...W
Note : all motors drop pressure are checked before shipping.
3.5.5.

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:
 
1
     
Pc 1 .Pn
ρ
 
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 : NK860W
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
 
1
 
 
= 1.8 kW
Pc 1 .20.9
 
0.92
So, the chiller must evacuate 1.8 kW and has a water flow of 5 l/min for this point of
running.
Drop pressure
0.5 bar
62 - PVD 3664_GB_NK-November 2016.Docx