Start Calculation

The most economical way to start a pump is to start it Direct On-line (D.O.L). The starting current however, is high. It can be as high as 6 or more times that of the nominal current. There are some situations where it is desirable to lower the starting current, e.g. a weak power supply.

There are 3 common starting methods which reduces the starting current:
star/delta start
auto transformer
solid state soft starter

There are generally no problems when starting a centrifugal pump direct on-line, but it is always good engineering practice to make a start calculation. Axial flow (propeller-) pumps may experience starting problems when they are started against filled systems. {Start calculations with SPAS}