What is a reduced voltage soft starter?

What does a reduced voltage soft starter do?

Reduced voltage soft starters (RVSS) are also known as soft starters.

A soft starter is a solid-state system or device that protects AC electric motors from damage caused by sudden influxes of power by limiting the large initial inrush of current associated with motor startup. RVSSs provide a gentle ramp up to full speed and are used only at startup (and stop, if equipped). Ramping up the initial voltage to the motor produces this gradual start. RVSSs reduce the voltage drop normally associated with motor starting.

How does a reduced voltage soft starter work?

Electrical soft starters temporarily reduce voltage or current input by reducing torque. Some soft starters may use solid-state devices to help control the flow of the current. They can control one to three phases, with three-phase control usually producing better results.

Most soft starters use a series of thyristors or silicon controlled rectifiers (SCRs) to reduce the voltage. In the normal OFF state, the SCRs restrict current, but in the normal ON state, the SCRs allow current. The SCRs are engaged during ramp up, and bypass contactors are pulled in after maximum speed is achieved. This helps to significantly reduce motor heating.

Why use a reduced voltage soft starter?

• Reduces voltage drop and peak currents associated with motor starting
• Mitigates mechanical stress on your system 
• Economical choice for applications that require speed and torque control only during startup/ramp down
• Eliminates ‘water hammer’ pressure surges on pump systems

Key features of our Ampgard RVSS