Why we use bypass contactor in soft starter?
Why we use bypass contactor in soft starter?
Soft starters protect AC electric motors at startup by reducing inrush currents and limiting torque. After the motor is up to speed, the soft starter transitions control over to a bypass contactor. The bypass contactor acts as “cruise control” because it allows the motor to continuously run at full speed.
How does a soft start contactor work?
Essentially, a soft starter works by controlling the amount of voltage running through the motors circuits. It does this by limiting torque in the motor. This in turn allows the soft starter to reduce the voltage and allows it to gradually stop reducing the voltage to allow for a smooth progression of current.
How do you connect a soft start?
The soft starter is installed between the mains and cable to the motor. If a mains or isolation contactor is used it is best controlled by the soft starter “Line relay”. 3Wire / 6wire: The standard connection of an electronic soft starter is 3 wire. An alternative connection is 6 wire or inside delta connection.
Do you need a contactor with a soft starter?
You don’t need the contactor for either control. You do need a disconnect thought for each. I agree with you regarding dropping out the power as this could lead to problems with braking or ramping to stop. You want the soft start to control what the motor does.
What is a bypass contactor in soft starter?
Bypass contactors bridge out a soft starter’s SCRs when the motor is running at full speed. This eliminates heat dissipation from the SCRs during run state. Some soft starters include built-in bypass contactors, others require an external bypass contactor.
Do I need a soft starter?
Soft starters are often the more economical choice for applications that require speed and torque control only during motor startup. Additionally, they are often the ideal solution for applications where space is a concern, as they usually take up less space than variable frequency drives.
Can you bypass a soft starter?
With an internal bypass soft starter, you only need power and control wiring. You do not need to purchase any additional devices. Internal bypass on a soft starter is perfect for conveyors, fans, pumps and other applications where the current and speed does not change while at speed.
Can you bypass a contactor?
Bypass contactors bridge out a soft starter’s SCRs when the motor is running at full speed. This eliminates heat dissipation from the SCRs during run state. Bypass contactors: Allow soft starters to be installed in sealed enclosures.
What is the advantage of soft starter?
A soft starter ensures smooth and uniform starting by torque control for gradual acceleration of the drive system which goes on to help in preventing jerks (in the case of phase 3 control starters). This extends the life of mechanical components and reduces their maintenance requirements.
What is a bypass contactor?
