7applications – Lenze DSD User Manual
Page 174
7
Applications
7.18
Pump
174
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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Required torque of the pump
From the data entered and the load characteristic selected the DSD calculates the required torque.
[7-168] Load characteristics of the pump
Calculation of the torque for a quadratic load characteristic (M ≈ n²):
[7-169] Equation 3: Torque for a quadratic load characteristic
Calculation of the torque for a constant load characteristic (M ≈ constant):
[7-170] Equation 4: Torque for a constant load characteristic
Tip!
• Further equations to complete the calculations required for an application can be
found in the chapter "
".
• The host computer "Energy efficiency fan/pump" serves to compare the energy de-
mand in an inverter-controlled and mechanically controlled system.
Constant characteristic (M ≈ constant)
Square-law characteristic (M ≈ n²)
Rated point of the pump
M
n
0
1
2
M
App
M
N
n
N
η
Pmp
-------------
2
J
add
α
⋅
+
⋅
=
M
App
M
N
J
add
α )
⋅
(
+
=