Working of Solenoid Valve: India Pneumatic Guide
The working of solenoid valve comes down to a simple electromechanical act: a coil energised by 24 V DC pulls a plunger that shifts the spool or poppet, opening or closing an air path. Carroland Pneumatics builds ISO 15218 miniature and industrial solenoid valves for packaging lines in Ahmedabad, tyre plants in Chennai, and electronics fabs across India. This guide covers the principle, the common configurations, and how to specify one for Indian supply voltage and dust conditions.
Core Components of a Solenoid Valve
A solenoid operated valve has four parts: the coil, the armature (plunger), the spring, and the valve body. When current flows, the magnetic field lifts the armature against the spring. De-energise and the spring returns the armature, which reseats the seal. Response time sits between 5 ms and 30 ms depending on coil power and spool mass.
Normally Closed vs Normally Open
A normally closed solenoid valve blocks flow until energised, which is the safe default for most Indian machines. A normally open valve flows until energised, used where air must stay on during a power cut. Choose normally closed for clamping and safety circuits.
| Configuration | Ports | Common task |
|---|---|---|
| 2/2 | 2 | Simple on-off air supply |
| 3/2 | 3 | Single acting cylinder control |
| 5/2 | 5 | Double acting cylinder direction |
How a Solenoid Valve Works in a Pneumatic Circuit
In a pneumatic valve circuit, the solenoid acts as the electric-to-air interface. A PLC output drives the coil; the valve then routes 1 to 10 bar air to the actuator. For a double acting cylinder, a 5/2 solenoid shifts air to extend or retract the rod. Add a soft-start valve and a filter-regulator upstream to protect the coil from moisture.
Specifying Solenoid Valves for India
Indian panels run 24 V DC control with IP65 enclosures. Specify Class F coils rated to 55 deg C ambient for unconditioned factories. Manual override is useful during commissioning. For food and pharma, choose stainless bodies; for general automation, anodised aluminium is enough.
BIS and Supply Notes
Solenoid valves fall under the broader pneumatic component scope that BIS monitors for the Indian market. Carroland ships with documentation and INR pricing for PLI-linked buyers. See our BIS-compliance components page for the current list.
Frequently Asked Questions
What is the working of solenoid valve in plain terms?
Energise the coil, the plunger lifts, the air path opens. Cut power, the spring pushes the plunger back, and the path closes.
When should I pick a normally closed solenoid valve?
Pick normally closed for clamping, lifting, and any circuit where a power loss must stop motion. It fails safe by blocking air.
Which voltage suits Indian control panels?
24 V DC is the standard for Indian machine builders. It keeps the coil current low and the wiring safe inside the panel.
How do I protect the coil from Indian humidity?
Use an IP65 rated coil, mount the valve away from direct wash-down, and fit a filter-regulator to keep the air dry. Dry air is the main defense against coil failure.