FSG PW 70d A/IP 65 Precision Rotary Resistance

FSG PW 70d A/IP 65 Precision Rotary Resistance Potentiometer

The FSG PW 70d A/IP 65 (Präzisionsdrehwiderstand / Precision Rotary Potentiometer) is an angular displacement feedback sensor engineered by FSG Fernsteuergeräte. Built specifically for demanding maritime, offshore, and heavy industrial drive environments, the PW 70d delivers high-accuracy linear resistance feedback across single-turn angular sweeps.

Enclosed in a rugged Type “A” die-cast housing sealed to IP65 (IEC/EN 60529), this rotary resistance unit resists continuous vibration, hydraulic fluid mist, engine room temperature fluctuations, and salt-laden atmospheres. Equipped with precision precious-metal wipers and a high-stability wirewound track, the PW 70d provides jitter-free position telemetry for closed-loop steering gear, azimuth thruster angle monitoring, variable-pitch propeller control, deck winch tensioning arms, and dancer-roller tension compensators.

Model Details

• Manufacturer: FSG Fernsteuergeräte Mess- und Regeltechnik GmbH (Germany)
• Series: PW 70 / PW 70d Series (Precision Wirewound Rotary Potentiometer)
• Housing Type: Type A Marine Heavy Flange Housing (Cast Iron / Aluminium Alloy)
• Protection Rating: IP65 (Dust-tight, water-jet protected)
• Shaft Specification: Ø 6.0 mm with flat/screwdriver slot, ground stainless steel
• Mechanical Protection: Integrated internal slip-clutch mechanism (protects winding against accidental over-rotation past internal end-stops)

Technical Details

Equipment Compatibility

• Propulsion & Steering Systems:
  • Rolls-Royce Marine / Ulstein Azimuth Thrusters & Steering Units (e.g., Aquamaster series)
  • Brunvoll & Schottel Steerable Propulsion Thrusters and Transverse Tunnel Thrusters
  • Tenfjord / Frydenbø Rotary Vane Hydraulic Steering Gears (Rudder angle feedback)
• Deck Machinery & Cranes:
  • MacGregor, Liebherr, and TTS Marine Deck Cranes (Boom angle, luffing gear, and slew position)
  • Anchor windlass, mooring winch spooling guides, and auto-tensioning dancer arms
• Control Room & Bridge Systems:
  • FSG Transmitters, G-Series gearboxes, and MU-series potentiometric-to-current converters (0/4–20 mA transmitters)
  • Engine room telegraph levers, helm wheel set-point units, and bridge console feedback indicators

Applications

• Rudder Angle Transmitter (RAT): Provides continuous, dynamic rudder blade positioning back to wheelhouse indicators, autopilots, and Voyage Data Recorders (VDR).
• Thruster Azimuth & Pitch Control: Direct-drive feedback tracking the 360° steering angle or the hydraulic variable-pitch propeller (CPP) blade angle.
• Valve Actuator Position Telemetry: Measures opening percentage on ballast, bilge, and cargo manifold hydraulic quarter-turn rotary actuators.
• Dancer-Arm & Tension Control: Monitors tensioner roller angles in continuous spooling systems, towing winches, and cable-laying gear.
• Heavy Machinery Boom/Jib Feedback: Angular monitoring on offshore work vessels, jack-up rigs, and knuckle-boom subsea cranes.

Frequently Asked Questions

What makes the PW 70d model different from the standard PW 70?

The “d” suffix signifies a double-wiper or multi-tap precision winding variant designed for specialized industrial bridge/differential circuits or redundant angular position feedback. It provides enhanced electrical stability and customized active angles compared to standard single-track models.

Can the FSG PW 70d A/IP 65 be used as a direct replacement for an IP40 version?

Yes, provided mechanical flange dimensions and electrical resistance ratings match. The IP65 version features upgraded shaft sealing and an O-ring sealed housing cover, making it a superior, ruggedized upgrade over standard IP40 units for high-moisture or washdown marine areas.

How do I check if my existing unit’s slipping clutch has slipped out of calibration?

Measure the output resistance at the physical neutral position (e.g., 0° rudder angle). If the center resistance has drifted while the mechanical linkage hasn’t moved, the slip clutch likely engaged during an over-travel event. Re-zero the potentiometer by adjusting the housing flange or the flexible coupling using a precision multimeter across Terminals 1, 2, and 3.

Is the electrical angle on the PW 70d 360 degrees?

Not necessarily. While the mechanical rotation can be continuous (360°), the active electrical winding angle is customized during manufacture (e.g., 40°, 60°, 172.5°, 340°, or 350°). Check the label on your existing FSG housing or contact technical support with your 1708Z… or 1700Z… serial number to confirm exact active angle values.

What is the typical service life of the wirewound resistance track under heavy continuous vibration?

Under standard operating conditions with wiper currents kept below 1 mA and a properly aligned flexible coupling, the FSG PW 70 series delivers an endurance rating exceeding 1 to 2 million complete sweep cycles before requiring track inspection or wiper refurbishment.