What Is a Solenoid Valve and How It Works in Pneumatics
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What Is a Solenoid Valve?
A solenoid valve is an electrically controlled valve used to start, stop, or direct airflow in a pneumatic system. It uses an electric coil to move an internal plunger, which opens or closes the airflow path.
These valves are commonly used in automation systems where airflow needs to be controlled without manual operation.
How a Solenoid Valve Works
A solenoid valve operates using a simple electrical process:
- Electrical current is applied to the coil
- The coil generates a magnetic field
- The magnetic field moves an internal plunger
- The plunger opens or closes the air passage
When power is removed, a spring returns the valve to its default position.
Electrical Coil Options (Voltage and Connection Types)
Solenoid valves are available with different coil configurations depending on the system’s electrical requirements and installation setup.
Common coil options include:
- DC12
- DC12W (wired)
- DC24
- DC24W (wired)
- AC110
- AC110W (wired)
- AC220
- AC220W (wired)
- AC DIN
- DC DIN
What These Coil Types Mean
DC vs AC Coils
- DC coils (12V, 24V) are typically used in control panels, PLC systems, and low-voltage automation
- AC coils (110V, 220V) are used in industrial environments with direct power supply
Wired Coil Versions
Wired versions (DC12W, DC24W, AC110W, AC220W) come with pre-attached lead wires.
This allows:
- Faster installation
- No need for separate connectors
- Simpler wiring in basic setups
DIN Connector Coils
DIN coils use a standardized plug-style connector.
They provide:
- Secure electrical connection
- Faster replacement during maintenance
- Consistent wiring across systems
Common Types of Solenoid Valves
2-Way Valves
- One inlet and one outlet
- Used for basic on and off control
3-Way Valves
- Adds an exhaust port
- Used for venting or single-acting cylinders
5-Way Valves
- Used with double-acting cylinders
- Controls extension and retraction
Where Solenoid Valves Are Used
- Automated machinery
- Pneumatic cylinders
- Conveyor systems
- Manufacturing equipment
- Control panels
How to Choose the Right Solenoid Valve
Selection depends on three main factors:
- Valve type (2-way, 3-way, 5-way)
- Voltage (DC or AC)
- Connection type (wired or DIN)
Matching all three ensures proper function and easier installation.
Final Thoughts
Solenoid valves control airflow using electrical signals, making them a core component in automated pneumatic systems. Correct valve type and coil selection are both required for reliable operation.