Switchboards suitable for starting small submerged pumps or submersible pumps, or for pressure boosting systems with surface pumps.
Each switchboard has power on, thermal relay tripped and motor running indicator lights, a manual or automatic circuit-breaker, and a master switch with door interlock system.
A terminal board allows connection to the users and to external control devices such as pressure switches, float switches, etc.
They can be completed with various options such as:
- Level relays for unipolar probes
- Alarm output relays
- Pump alternating relays
- Analogue voltmeters of suitable scale
- Voltmeter switch on 3 phases
- Phase sequence and missing phase control
- Min and max voltage control
- Start/stop button
- Mushroom emergency button
- Operating hour counter
Direct on line starting
Direct on line starting is perhaps the most simple, traditional method: the motor is connected directly to the mains power supply and is thus started at full voltage.
It is often abbreviated to DOL starting.
DOL starting is the simplest, most economical way of starting electric pumps or motors and is traditionally the most widely used method. The current induced in the rotor is high. This causes a current surge in the system which may be from 5 to 8 times the rated current.
They are suitable for starting small submerged pumps or submersible pumps, or for pressure boosting systems with surface pumps.
With the DIRECTO switchboard, units are connected directly to the mains power supply, which implies:
- Start-up at full voltage and constant frequency
- High starting torque
- On average, very short acceleration times