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

Details of SG3-AA125-A2(W) Three phases Input 80-280VAC Output 48-480VAC Current 125A Zer

SG3-AA125-A2(W) Three phases Input 80-280VAC Output 48-480VAC Current 125A Zer Solid State Relay (SSR) is a three-phase device that uses AC voltage for both input and output to control alternating current circuits without the need for mechanical contacts of conventional relays. Let's look at each detail.

Working Principle of Three-Phase SSR

A three-phase SSR operates using electronic circuits such as thyristors (Thyristor) or Triac 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 Output load 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 current switching (zero crossing) to reduce interference and voltage spikes. There is no mechanical contact movement: hence there are no click-click sounds like conventional relays, and there is no mechanical wear.

Features of Three-Phase SSR

• Input AC Voltage Type 90~280V (typically)
• Output AC Voltage Type 24~480V or higher (depending on the model)
• Current Capacity from 10A to 100A or more
• No moving parts, no wear and tear, 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 applications requiring quiet operation
• Fast and accurate electrical switching
• Durable against vibrations

Cautions:

• Proper heat sink selection is necessary → Prevent overheating.
• Avoid leakage current issues when in the off state.
• Inappropriate for loads with very high surge voltages (unless additional protection circuits are added).

Tech Data SG3-AA125-A2(W) Three phases Input 80-280VAC Output 48-480VAC Current 125A Zer