KSB RPH - Fluid Handled

6.2.2 Frequency of starts
DANGER
Excessive surface temperature of the motor
Explosion hazard!
Damage to the motor!
▷ In case of explosion-proof motors, observe the frequency of starts specified in
the manufacturer's product literature.
The frequency of starts is usually determined by the maximum temperature increase
of the motor. This largely depends on the power reserves of the motor in steady-
state operation and on the starting conditions (DOL, star-delta, moments of inertia,
etc). If the start-ups are evenly spaced over the period indicated, the following limits
serve as orientation for start-up with the discharge-side gate valve slightly open:
Table 15: Frequency of starts
Motor rating
[kW]
Maximum number of start-ups
[Start-ups/hour]
up to 12 15
up to 100 10
more than 100 5
CAUTION
Re-starting while motor is still running down
Damage to the pump (set)!
▷ Do not re-start the pump set before the pump rotor has come to a standstill.
6.2.3 Fluid handled
6.2.3.1 Flow rate
Unless specified otherwise in the characteristic curves or in the data sheets, the
following applies:
Q
max
9)
See characteristic curves.
Q
min
10)
= 0.3 × Q
opt
11)
The data refer to water and water-like fluids. Longer operating periods with these
fluids and at the flow rates indicated will not cause an additional increase in the
temperatures on the pump surface. However, if the physical properties of the fluids
handled differ from those of water, the calculation formula below must be used to
check if an additional heat build-up may lead to a dangerous temperature increase at
the pump surface. If necessary, the minimum flow must be increased.
×
×
×
Table 16: Key
Symbol Description Unit
c Specific heat capacity J/kg K
g Gravitational constant m/s²
9)
Maximum permissible flow rate
10)
Minimum permissible flow rate
11)
Best efficiency point
6 Commissioning/Start-up/Shutdown
RPH
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