Pump and level control
Manual and Automatic Star–Delta Starting with Float Switch – 1
What is manual-automatic star-delta pump starting with float switches?
In this control circuit a large pump motor starts with star-delta in both manual and automatic mode. In automatic the float switches start and stop the pump; in manual the operator uses start-stop buttons. In both modes the starting current is reduced by star-delta starting.
Where is it used?
It is used for deep well pumps, large irrigation systems, municipal water tanks and large building water systems. It is the choice where starting large pumps direct-on-line would strain the supply.
Power circuit and control circuit
The power circuit has the main, star and delta contactors and an overload relay. In the control circuit a timer relay, an auxiliary contactor, a selector switch, buttons and float switches work together. It is an advanced pump panel that combines star-delta starting and level control in one circuit.
What to watch out for
The float switches' level range is kept wide; large pumps starting and stopping too often wear out both the motor and the contactors. The timer is set by how long the pump takes to reach speed.
Parts used
- Contactor coil
- K3, K1, K2, KA
- Float switch
- USF1, ASF2
Run it in the simulator.
This circuit is ready in the CoilPath library. Open it, press the buttons and follow the current. It also comes with a wiring view and a panel layout.
Related circuits
- Manual and Automatic Star–Delta Starting with Float Switch – 2
- Liquid Level Relay – NO Contact Circuit Application
- Liquid Level Relay – NC Contact Circuit Application
- Liquid Level Relay – Two-Tank Water Transfer System
- Manual and Automatic Pump Operation in a Two-Tank Water Transfer System with Liquid Level Relay
- Manual and Automatic Pump Operation Using a Liquid Level Relay (NO Contact) and Float Switch