Lenze DSD - 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 " Basic calculations ". ( 68)
• 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 ) ⋅ ( + =