Flow Velocity "V" Past The Motor - KSB S 100D Booklet

Flow Velocity v Past the UMA Submersible Motor
Depending on the general installation arrangement (i.e. depending, for example, on the ratio of outside motor diameter to inside
well or shroud diameter, etc.) a distinction must be made between the following cases ...
a) v = 0 m/s ... this applies, for example, when the pump set is installed in a deep well below the well screen / filter, in a pump
sump, tank or other reservoir, etc.
Caution: At v = 0 m/s, UMA 250D motors can only be operated at reduced rated power.
b) v ≥ 0.2 m/s ... this describes with adequate accuracy the case when the pump set is, for example, installed in a deep well above
the well screen / filter, etc. In borderline cases (for ex. if the inside well diameter is very large compared with the outside motor
diameter) the diagram below can be used to double-check the data.
c) v ≥ 0.5 m/s ... In this case it must always be checked, using the diagram below, whether the installation dimensions (i.e. the ratio
of outside motor diameter to inside well diameter) are adequate to ensure a minimum flow velocity past the motor of v ≥ 0.5 m/s. If
not, use a special cooling shroud.
How to read the diagram:
The requirement for a "flow velocity past the motor of v ≥ 0.2 or 0.5 m/s" is met, if the point of intersection of the capacity Q and
the inside well or shroud diameter DN is located on or to the right of the curve applicable to the submersible motor used.
1400
1200
∅
[mm]
1000
800
DN 100V > 0.1
600
400
200
0
0 100
Example:
Given: UPA 300 - 65/4 + UMA 250D 160/21 and v ≥ 0.2 m/s.
3
Found: For Q = 250 m
This means that the requirement for v ≥ 0.2 m/s is met, if the pump set is, for example, installed in a well or cooling shroud of
DN ≤ 700 mm or ≤ 28 inches.
108
Max. permissible well diameter for compliance with
required flow velocity past the motor
200 300
/h (≈ Q ) the following applies: ⇒ DN ≤ 700 mm.
opt
50 Hz
400 500 600
Submersible borehole pumps
V >= 0.2 m/s
V >= 0.5 m/s
UMA 300D
UMA 250D
UMA 200D
UMA 150D
DN 100
700 800 900
Q [m#/h]