Switching volume & starts per hour Too small an effective sump volume means too many motor starts. This tool determines the required switching volume from the permissible number of starts of the motor.
Input (Technical book, chap. 4.1.6)
l/s
1/h
l/s
Result
Required effective volume VN
– m³
Starts per hour at the entered inflow: – 1/h
–
VN = Q · 3600 / (4 · Z) = 0,9 · Q / Z (Q in l/s → V in m³)Zist = 3600 / ( VN/Qzu + VN/(Q − Qzu) )The highest number of starts occurs at Q_in = Q/2 – V_N is sized for this case.
| Reference | Technical book, chap. 4.1.6 · Starts per hour and motor protection |
|---|---|
| Example | Chap. 4.4.12 · Pumping station with redundancy |
| Note | Valid for one pump. The permissible number of starts is specified by the manufacturer and depends on motor size and starting method. |