Bently Nevada 330750-20 High Temperature Velomitor System

Description

Option 20 (2 meters integrated hardline cable length) specifies this High Temperature Velomitor System configuration — 330750-20. This industrial piezoelectric velocity sensor segregates the sensing element from the signal conditioning electronics, enabling reliable machinery casing vibration monitoring in extreme thermal environments. With this design, the sensing head can be mounted on surfaces reaching temperatures up to 400 degC (752 degF).

By using a permanently connected integrated hardline cable, the 330750-20 eliminates intermediate connectors, which are a major source of signal loss and mechanical transducer failures in hot zones. The 2-meter cable allows the signal conditioning electronics to be positioned in a cooler location with operating temperatures from -55 degC to 121 degC (-67 degF to 250 degF) to preserve long-term reliability. This system captures high-quality casing velocity measurements comparable to standard velocity sensors but at significantly higher operating temperatures.

Features

• Option 20 Cable Length: Includes a 2-meter integrated hardline cable connecting the sensing head directly to the conditioning electronics.
• Extreme Temperature Support: Sensing head and hardline cable withstand operating surface temperatures up to 400 degC (752 degF).
• Segregated Transducer Design: Places delicate signal conditioning electronics in a separate housing to run in a cooler zone.
• Connectorless Sensor Interface: Permanent hardline cable attachment prevents connector fatigue and failure in extreme heat.
• Nominal Velocity Output: Standard 5.7 mV/mm/s (145 mV/in/s) sensitivity for direct integration with Bently Nevada machinery protection monitors.
• Hermetically Sealed Head: 300-series stainless steel case protects against moisture and severe industrial environments.

Applications

• Gas and steam turbine casing vibration monitoring
• High-temperature exhaust duct and piping analysis
• Exhaust gas expander casing measurements
• Boiler feed pumps and extreme-temperature rotating machinery protection

Ordering Information

Technical Specifications

Connections and Interfaces

Installation Guidelines

• Cable Bend Radius: Maintain a minimum bend radius of 51 mm (2.0 in) for the integrated hardline cable to prevent internal conductor damage.
• Environmental Protection: Position the signal conditioning electronics inside a weatherproof enclosure with wiring protected in conduit for outdoor installations.
• Mounting Surface: Secure the sensing head to a flat, smooth, clean surface with correct torque to facilitate high-frequency vibration transfer.
• Thermal Considerations: Verify that the signal conditioning electronics housing does not exceed its maximum operating limit of 121 degC.

Compliance and Certifications

• ATEX Directive 2014/34/EU
• EMC Directive 2014/30/EU
• RoHS Directive 2011/65/EU
• Hazardous Area Approvals (with safe barrier): Class I, Division 1, Groups A, B, C, D (T4/T1); Class I, Zone 0, Ex ia IIC T4/T1 Ga; Class I, Division 2, Groups A, B, C, D; Class I, Zone 2, Ex ec IIC T4/T1 Gc