Product Description

The 3500/53 (133388-01) is a high-speed Overspeed Detection Module engineered to provide mission-critical protection for rotating machinery. Built to comply with rigorous API 670 and API 612 standards, this module monitors tachometer inputs and executes emergency shutdown logic within milliseconds of detecting an overspeed condition. Unlike standard tachometer modules, the 3500/53 (133388-01) is specifically designed as a redundant system, typically used in a two-out-of-three (2oo3) voting configuration to ensure the highest level of reliability and prevent nuisance trips.

The module continuously tracks rotational speed via proximity probes or magnetic pickups. It provides local relay outputs for direct hardware interlocking and analog recorder outputs for integration with distributed control systems (DCS). Its robust architecture and rapid response time make it the industry standard for protecting steam turbines, gas turbines, and large centrifugal compressors from catastrophic overspeed damage.

Technical Specifications

• Module Type: Overspeed Detection Module

• Part Number: 133388-01

• Series: Bently Nevada 3500

• Input Signal Range: +10 V to -24 V

• Input Impedance: 20 kΩ

• Transducer Power Supply: -24 V DC, 40 mA maximum

• Power Consumption: 8 Watts (Typical)

• Analog Output: 4–20 mA (Proportional to full-scale RPM)

• Analog Resolution: 0.3662 µA per bit

• Analog Accuracy: ±0.25% (Room temp); ±0.7% (Full operating range)

• Relay Type: Single-Pole Double-Throw (SPDT)

• Relay Contact Ratings: 5 A @ 24 V DC / 120 V AC

• Maximum Relay Voltage: 30 V DC / 250 V AC

• Relay Life: 100,000 cycles at rated load

• Operating Temperature: -30 °C to +65 °C (-22 °F to +150 °F)