The Non-Magnetic Pickup Coil (Part Number: 644327401 / 644327-401), manufactured by Smith Meter (a division of TechnipFMC, USA), is a precision-engineered sensing component responsible for converting the mechanical rotation of a flow meter's rotor into a measurable electrical frequency.

Technological Advantage of the Non-Magnetic Design:
Standard reluctance pickup coils contain an internal permanent magnet. As ferromagnetic turbine blades pass the coil, the magnetic field is disturbed, generating a voltage pulse. However, the continuous attraction between the internal magnet and the passing blades creates "magnetic drag" (or cogging torque). While negligible at high velocities, this drag significantly impairs the rotor's ability to spin freely at low flow rates, negatively impacting the meter's linearity and accuracy at the bottom end of its measurement range.

To resolve this, Smith Meter developed the Non-Magnetic Pickup Coil (644327401):
- Zero Magnetic Drag: By omitting the permanent magnet from the coil core, the sensor exerts absolutely no magnetic pull on the turbine blades. The rotor spins freely with zero magnetic resistance, vastly improving the meter’s turndown ratio and ensuring exceptional measurement linearity even at the lowest flow rates.
- Inductive/Modulated Operating Principle: Typically used in conjunction with magnetized rotor buttons or integrated into a high-frequency modulated carrier (RF) preamplifier circuit, this coil senses the passage of the rotor without physical or magnetic interference.
- Superior Custody Transfer Performance: The elimination of drag ensures that the rotor speed remains perfectly proportional to fluid velocity (maintaining a highly stable K-Factor), meeting and exceeding strict API custody transfer measurement standards.

Heavy-Duty Industrial Construction:
Designed for harsh refinery and pipeline environments, the coil is housed in a rugged, threaded stainless steel body that resists chemical corrosion. The internal copper windings are completely encapsulated (potted) in industrial-grade epoxy, making the sensor highly resistant to moisture, thermal shock, and mechanical vibration. The threaded body screws directly into the flow meter pressure housing and locks into place with a jam nut. The two-wire lead integrates flawlessly with the Smith Meter PA-6 Preamplifier (Model 230663101), supporting Class I, Division 1 explosion-proof system requirements when installed in a proper junction box.

Typical Industrial Applications:
- Factory replacement and performance upgrade for Smith Meter Turbine Flow Meters (Sentry Series and Guardsman Series).
- High-accuracy Custody Transfer metering stations (LACT units, pipeline terminals, and marine offloading facilities) requiring extensive turndown ratios.
- Dual-channel (redundant) pulse sensing configurations for pulse fidelity checking (API Chapter 5.5 compliance) where adding a second magnetic coil would otherwise double the unwanted drag on the rotor.

• Manufacturer: Smith Meter (Smith Meter Inc. / TechnipFMC)
• Country of Origin: 100% United States of America (Made in USA)
• Component Designation: COIL-PICK-UP NON-MAGNETIC
• Part Number / SKU: 644327401 (644327-401)
• Sensor Type: Non-Magnetic Pickup Coil (Contains no internal permanent magnet, eliminating magnetic drag on the rotor)
• Function: Captures rotor motion and translates it into an electrical signal (requires compatible preamplifier)
• Compatible Preamplifier: Integrates directly with Smith Meter PA-6 Preamplifier Assembly (Part No. 230663101) or equivalent modulated carrier/RF preamps
• Compatible Meter Families: Smith Meter Turbine Flow Meters (Sentry Series, Guardsman Series) and D-Transmitters
• Electrical Connection: 2-wire flying leads (typically White and Black), insulated with high-temperature Teflon (PTFE)
• Housing Metallurgy: Machined Stainless Steel body for superior corrosion resistance
• Internal Protection: Fully epoxy-potted internal cavity to protect against moisture ingress, vibration, and thermal shock
• Hazardous Area Suitability: Suitable for installation in Class I, Division 1, Groups C & D environments when installed in the meter's certified explosion-proof junction head
• Mechanical Mounting: Standard UNF external threaded body equipped with a locking jam nut for precise depth adjustment into the meter housing
• Operating Temperature Range: Designed to withstand severe industrial ambient and fluid temperatures (typically -40°C to +85°C, or higher depending on meter specification)
• Product Condition: 100% Brand New, Genuine OEM Factory Part.