Pizzato FK 301 Position Switch with Plunger, Snap Action

Compact technopolymer plunger switch with a 1NO+1NC snap-action block

The FK 301 is a compact Pizzato Elettrica position switch with a plunger head. Its technopolymer housing has one threaded PG 11 conduit entry as shown on the product page, and the contact block is the snap-action 1NO+1NC type 3 (B3), which changes over quickly regardless of how slowly the plunger is pressed. That makes it an easy match to slow-moving machine parts where creeping contact would otherwise cause arcing.

The FK series has only three contact blocks (3, 33 and 34) but 47 actuators, so the choice at order time is mainly about the head. IP67 and IP69K protection are listed on the product page.

Technical specifications

Snap action versus slow action

Contact block 3 is a snap-action 1NO+1NC. Blocks 33 and 34 in the same series are slow-action, 1NO+1NC and 2NC respectively. The snap-action block suits low actuation speeds and frequent signalling; the slow-action blocks with positive opening are preferred when the NC contact is used in a safety circuit. The catalogue’s wording is that safety circuits must be wired to the NC contacts of switches marked with the positive-opening symbol, so confirm the marking before using FK 301 for safety.

The chapter shows the selection grid for heads: plungers, short plungers with external gasket, rollers, adjustable levers, rods, a rope head for signalling, and reset versions with the W3 designation.

Ordering notes

The code structure FK 302-W3XGM2K24R23T6 shows how a base code is extended with a reset device, gold contacts, an entry thread (M2, M1, PG 13.5 or PG 11), a cable gland such as K24 for 5 to 10 mm cable or an M12 plastic connector, a temperature option and a roller material. FK 301 itself is the plain version without these options.

Please confirm head type, contact block and entry thread before ordering. Pizzato notes that not every combination of options is available.

Features and construction

The housing is glass-fibre reinforced technopolymer, a material that does not corrode and tolerates washdown, which is why the product page quotes both IP67 under EN 60529 and IP69K under ISO 20653 when a suitable cable gland is fitted. The manufacturer also publishes an EU declaration of conformity under the Low Voltage Directive and a UKCA declaration, and the printed approvals include IMQ, UL, CCC and EAC. The 20 million operating cycle rating and the 3600 cycles per hour frequency help when sizing the switch for frequent signalling, such as a part counter or an end-of-stroke sensor on a pneumatic slide.

• Plunger head: the switch is actuated by a straight push along the plunger axis, so the cam or the machine part should approach in line with it.
• Snap-action block 3: contacts change over at a fixed point of travel, independent of actuating speed.
• Item documents available from the maker include a data sheet, a 2D drawing and a 3D model for the machine designer.

Typical applications

A plunger position switch of this kind is used to confirm that a guard, slide, pallet, door or carriage has reached a defined position. Typical places are packaging lines, conveyors and transfer machines, machine tools, lifting platforms and food or beverage areas where washdown is common. The signal is normally wired to a PLC input or to a contactor. When the contact is part of a safety function, the circuit should use a positive-opening device and not a general-purpose snap-action block.

Installation and wiring notes

• Mount the switch on a rigid surface and align the plunger so it is not hit from the side; a lateral load shortens plunger and seal life.
• Do not set the stroke so that the plunger bottoms out. Leave overtravel for the actuating cam, and secure the switch with the fixing screws at the torque given in the catalogue.
• Use a cable gland suited to the cable diameter and to the conduit thread; the IP rating depends on the gland and on its correct fitting.
• Keep the load within the AC-15 and DC-13 values in the table above, and add a suitable fuse in series, as stated in the catalogue.
• Where the switch is exposed to dust or sand common in Gulf plants, wipe the plunger area periodically and check that it returns freely.

Choosing between FK variants

The FK 301 uses the plunger head with block 3. If the moving part approaches at an angle, a roller or lever head from the same series will usually be better than a plunger. If a slow-action contact with positive opening is needed, the other blocks of the series are the starting point. Because a different head or block changes the order code, confirm the machine movement, available travel and wiring before comparing codes.

Information needed for a quotation

• Full Pizzato type code, including head and contact block
• Conduit thread or connector type and cable gland requirement
• Operating voltage, current and type of load
• Ambient temperature and washdown or dust exposure
• Quantity and delivery location

Documents and quotation

The manufacturer document (Pizzato General Catalogue Detection 2025-2026, FK series position switches, pages 91-100 (manufacturer, unaltered)) is attached to this page as a PDF. Send the complete type code or part number you need through the quotation form and we will reply with availability and delivery terms; please confirm the head, contact block and entry thread against the plant specification before ordering. More in Automation Accessories.