SG3-AA125-A2 Three phases Input 80-280VAC Output 48-480VAC 125A Zero C

Details of SG3-AA125-A2 Three phases Input 80-280VAC Output 48-480VAC Current 125A Zero C

SG3-AA125-A2 Three phases Input 80-280VAC Output 48-480VAC Current 125A Zero C Solid State Relay (SSR) is a three-phase electronic device that controls AC circuits without the mechanical contacts of conventional relays. Let's look at each detail.

Operation Principle of Three Phase SSR

A three-phase SSR operates using electronic circuits such as thyristors or Triacs to switch electrical circuits on and off.

• When AC power is applied to the Input: The internal control circuit activates the thyristor/Triac. This control signal may be around 90~280V AC (depending on the model).
• The load Output side works (AC as well): Power will pass through three phases to the load, such as motors, heaters, industrial furnaces. The output circuit uses synchronized AC switching (zero crossing) to reduce noise and voltage spikes. There is no mechanical contact movement: hence there are no click-click sounds like conventional relays, and there is no wear.

Features of Three Phase SSR

• Input AC Voltage Type 90~280V (generally)
• Output AC Voltage Type 24~480V or higher (depending on the model)
• Current Capacity from 10A to 100A or higher
• No moving parts, no wear, long service life
• Silent circuit switching, no operational noise
• Durable in environment, no sparks, not sensitive to dust or moisture
• Installation: Usually mounted with a heat sink for cooling.

Applications

• A three-phase SSR is often used in applications requiring stability and speed control of electrical loads such as:
• Three-phase heating systems (Three-phase heater systems)
• Industrial ovens, plastic injection machines, forming presses
• Control of three-phase motors (without the need for speed control)
• Automated machinery
• In production lines requiring fast and accurate load switching
• Temperature control devices
• Using SSR to control power input to a heater through temperature controllers (PID Controller).

Advantages:

• No mechanical contacts → Long service life
• No noise → Suitable for quiet applications
• Fast and accurate electrical switching
• Durable against vibrations

Cautions:

• Must choose an appropriate heat sink → Prevent overheating accumulation.
• Be cautious of minor leakage current when in the off state.
• Inappropriate for loads with very high surge voltages (unless additional protection circuits are provided).

Tech Data SG3-AA125-A2 Three phases Input 80-280VAC Output 48-480VAC Current 125A Zero C