The AirTAC Airtac 3V Solenoid Valves 3V308NOBT is a genuine 3-port 2-position (3/2) solenoid valve with 1/4 in ports. It either feeds its outlet or vents it to exhaust, which is what makes it the valve for single-acting cylinders, on/off air blow, clamping, vacuum switching and pilot duty.
The 3V308NOBT is AirTAC's normally open 3/2 valve in the largest, highest-flow 3V body, built in an NPT1/4 configuration for imperial pipework. With power on, the outlet stays connected to supply; de-energise it and the spring return vents the line to exhaust. That makes it the natural choice for fail-vent duties, where a control fault or power cut must let a clamped part or a cylinder release rather than hold. It is direct-acting with a single solenoid and a coaxial poppet, so there is no pilot pressure needed to shift it and sealing stays tight across the full 0-0.8 MPa span, down to -102.2 kPa for vacuum service. Flow is the headliner: Cv 0.62, roughly three times the Cv 0.19 of a 3V208. The 24 V DC coil draws 6.5 W and terminates in a DIN plug socket on the coil body, keeping panel wiring standard.
| Model | Airtac 3V Solenoid Valves 3V308NOBT |
|---|---|
| Series | 3V3 |
| Valve type | 3/2-way (3-port, 2-position) |
| Function | Direct-acting, single solenoid, spring return |
| Initial state | Normally open |
| Port size | 1/4 in |
| Thread | NPT |
| Coil voltage | DC24V |
|---|---|
| Electrical entry | DIN plug (DIN socket type) |
| Coil power | 6.5 W |
| Operating pressure | 0-0.8 MPa (0-114 psi) |
| Vacuum service | Rated -102.2 kPa to 0.1 MPa |
| Flow coefficient | Cv 0.62 |
| Temperature | -20 to 70 C |
| Construction | Coaxial shut-off (poppet), direct-acting, spring return |
| Protection | IP65 (DIN 40050) |
| Medium | Air, filtered by a 40 µm or finer element. Lubrication not required. |
Figures follow the official AirTAC 3V3 catalogue. Confirm coil voltage and thread (PT / NPT / G) against the product label before wiring.
| 3V3 | Body — sets the flow, the coil power and whether vacuum is rated. |
|---|---|
| 1/4 in | Port size. M5, 06 = 1/8 in, 08 = 1/4 in, 10 = 3/8 in. |
| NO | Normally open: air passes until the coil is energised. |
| DC24V | Coil voltage. A = AC220V, B = DC24V, C = AC110V, E = AC24V, F = DC12V. |
| — | Electrical entry: I = flying lead, otherwise a DIN plug. |
| NPT | Port thread. PT ships from stock; G and NPT are available to order. |
A 3/2 valve has three ports — supply, outlet and exhaust — and two states. It either feeds the outlet or vents it to exhaust, and that is the whole job.
That makes it the right valve for a single-acting (spring-return) cylinder, on/off air blow, a clamp, switching a vacuum generator or suction cup, and piloting a larger valve.
It cannot run a double-acting cylinder. A double-acting cylinder needs air alternately on two sides, which takes a 5-port valve — the AirTAC 4V series.
A larger spring-return pusher cylinder advances pallets into a carton wrap station. NO logic vents the line and retracts the pusher whenever the DC24V output drops, so a jam or power loss leaves the conveyor path clear.
High-volume air clears chips from a fixture between cycles. The Cv 0.62 bore supports the wide blast nozzle, and the normally open function purges for as long as 24 V power stays on - a fault simply stops the blast.
Big vacuum cups hold blank boards on the bed. The valve, rated -102.2 kPa to 0.1 MPa, sits in the vacuum line and, being normally open, it holds continuity until energised - wire it so the break command energises the coil and the spring return vents the cup to release the board.
Pick the 3V308NOBT when your panel runs 24 V DC, the machine uses NPT fittings and you need a normally open function with real flow headroom. If NO is the wrong fail state, choose the NC version of the same body instead. Step down to a 3V2 (Cv 0.18-0.19, 1/8in or 1/4in, also vacuum-rated) when 0.62 is more coefficient than the job needs, to the 3V2M (Cv 0.1) when a compact multi-station manifold beats raw flow, or to the 3V1 (3.0 W on DC24V) for the smallest low-power circuits. Confirm five points before ordering: port size and thread (this code is NPT; PT is the family default and G/BSPP is a catalogue option), NC or NO, coil voltage, electrical entry (DIN plug here, flying lead with the I suffix), and whether vacuum duty applies. If the target is a double-acting cylinder, move to the AirTAC 4V 5-port series instead.
Confirm before you order
It is a 3/2-way, direct-acting, single-solenoid, spring-return valve in normally open form. Port NPT1/4. Flow coefficient Cv 0.62, the highest in the AirTAC 3V range. Operating pressure 0-0.8 MPa, with vacuum service rated -102.2 kPa to 0.1 MPa. Temperature range -20 to 70 C. Coil power 6.5 W on DC24V (AC versions of the body are 10 VA). Protection class IP65 (DIN 40050). Air should be filtered to 40 um or finer; lubrication is not required. A manual override is fitted for commissioning.
It feeds or vents one line, so it suits single-acting (spring-return) cylinders, blow-off, clamping, vacuum switching and piloting a larger valve. It cannot drive a double-acting cylinder - that takes a 5-port valve such as the AirTAC 4V series. On the thread: the T in this order code selects the NPT option for imperial fittings, while PT tapered is the standard thread of the 3V3 family and G/BSPP parallel is also a catalogue choice to order. Choose NO over NC when the circuit must pass air or keep the vacuum path open while de-energised, and vent or seal only when the 24 V coil is energised.
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