Bently Nevada 74712-06-05-04-00 Velocity Transducer

Bently Nevada 74712-06-05-04-00 High-temperature Two-wire Transducer

Product Introduction

The Bently Nevada 74712-06-05-04-00 belongs to the Seismoprobe family of velocity transducers, utilizing moving-coil technology for absolute vibration measurement. Specifically, this two-wire transducer measures bearing housing, casing, or structural vibration relative to free space. Its high-temperature rating makes it suitable for steam turbines, gas turbines, and other equipment operating in extreme thermal environments. Furthermore, the model 74712-06-05-04-00 provides a voltage output directly proportional to the transducer's vibration velocity. Consequently, this transducer offers a reliable solution for machinery protection and monitoring applications where elevated temperatures are present.

Technical Specifications

The 74712-06-05-04-00 High-temperature Transducer delivers precision velocity measurements with a comprehensive set of electrical and mechanical features.

Sensitivity and Output

The transducer provides a sensitivity of 20 mV/mm/s (500 mV/in/s) with an accuracy of ±5% when properly terminated and oriented at the calibration angle. Specifically, the output is taken across pins A and B with a calibration load of 10 kΩ. The polarity of the output signal is defined as follows: pin A goes positive with respect to pin B when the transducer case velocity moves towards the connector. Additionally, the sensitivity temperature coefficient is 0.2%/°C, ensuring stable performance across the operating temperature range.

Dynamic Range and Velocity

The dynamic operating range reaches a maximum displacement of 2.54 mm (0.100 inch) peak to peak. Meanwhile, the velocity range extends to 25 mm/s (1 in/s) at +22°C of casing vibration at 100 Hz with a 10 kΩ load. Furthermore, the amplitude linearity holds within ±5% from 0.01 to 5.0 in/s (0.254 to 127 mm/s) at 100 Hz (6000 CPM), providing accurate measurements across a broad operating spectrum.

Electrical Characteristics

The coil resistance measures 1.25 kΩ ±5%, and the locked coil inductance is typically 125 mH. Moreover, this moving-coil design does not require external power, making it convenient for portable measurement applications. However, note that Bently Nevada's Velomitor family with solid-state technology may provide improved performance and ruggedness for most casing velocity measurement applications.

Mechanical Specifications

Mounting Configuration

Option 06 designates the transducer mounting angle and minimum operating frequency as 0° ±100, 10 Hz (600 CPM). The mounting base option is 05, which means no base is provided; instead, the unit uses a 1/2-20 UNF-3A stud. For proper installation, apply a mounting torque of 5.6 N•m (50 in•lb) for the 1/2-20 stud. For 8-32 threaded studs, the torque specification is 1.41 N•m (12.5 in•lb).

Connector and Dimensions

Option 04 specifies a side-mount connector configuration. The transducer height is 82 mm (3.2 inches), with a typical height of 102 mm (4.0 inches) depending on the connector option. The diameter measures 41 mm (1.6 inches) typically. These compact dimensions facilitate installation in confined machinery spaces.

Environmental Specifications

Temperature Range

The 74712-06-05-04-00 operates in temperatures from -29°C to +204°C (-20°F to +400°F). Furthermore, the storage temperature range matches the operating range, providing flexibility for inventory management. This extended temperature capability distinguishes this transducer from standard models.

Humidity and Altitude

The transducer performs reliably in relative humidity up to 95% non-condensing. For units ordered with integral cable, it can withstand 100% humidity when non-submerged. Moreover, the maximum use altitude is 2000 meters (6,561 feet) above sea level.

Shock and Transverse Sensitivity

The transducer withstands 50 g peak maximum acceleration along the non-sensitive axis, providing robustness against incidental mechanical shocks. The transverse sensitivity is ±10% maximum of the sensitive axis sensitivity at 100 Hz and 1.0 in/s (2.54 cm/s). Therefore, this minimizes measurement errors from cross-axis vibration.

Agency Approvals and Certifications

Option 00 designates no agency approvals for this model. Therefore, the 74712-06-05-04-00 is not certified for installation in hazardous area applications. For environments requiring explosion-proof equipment, consider models with approval option 01 or other certified variants within the 74712 series.

Installation and Wiring Guidelines

Proper installation of the 74712-06-05-04-00 ensures optimal measurement accuracy and reliability.

Cable Length Considerations

The lead wire length should not exceed 305 meters (1,000 feet) between the transducer and the 3300 or 3500 monitor. For longer distances, consult the manual regarding frequency roll-off effects. Therefore, careful planning of cable routing is essential for maintaining signal integrity.

Mounting Procedure

First, clean the mounting surface thoroughly to ensure proper contact. Next, thread the 1/2-20 UNF-3A stud into the mounting hole using the recommended torque of 5.6 N•m (50 in•lb). Meanwhile, avoid overtightening as this may damage the threads or affect measurement accuracy. Additionally, orient the transducer so that the connector is positioned for convenient cable access.

Wiring Connections

Connect the output leads to pins A and B as specified in your monitoring system documentation. For optimum performance, use a 10 kΩ termination load across pins A and B. The polarity is defined as pin A positive with respect to pin B when the transducer case velocity is towards the connector.

Packaging List

Each order of the Bently Nevada 74712-06-05-04-00 includes the following items:

• One Bently Nevada 74712-06-05-04-00 High-temperature Two-wire Transducer

• One 1/2-20 UNF-3A mounting stud pre-installed

• Side-mount connector assembly

• Product installation and wiring guide

All items ship in protective packaging to prevent damage during transportation.

Shipping Information

We ship all orders via FedEx, UPS, or DHL. Additionally, each package includes tracking information for convenient shipment monitoring. Standard delivery typically takes 3 to 5 business days depending on the destination.

Frequently Asked Questions

1. What is the primary application for the 74712-06-05-04-00 transducer?

This transducer is specifically designed for measuring absolute casing vibration on rotating machinery operating at elevated temperatures. For instance, it is commonly used on steam turbines, gas turbines, and other equipment where temperatures reach up to +204°C (+400°F).

2. What is the difference between moving-coil and solid-state velocity transducers?

Moving-coil transducers like the 74712-06-05-04-00 are less sensitive to impact or impulsive excitation and do not require external power. However, Bently Nevada's Velomitor family with solid-state technology typically provides improved performance and ruggedness for most casing velocity measurement applications.

3. What is the maximum cable length for this transducer?

The maximum lead wire length between the transducer and the 3300 or 3500 monitor is 305 meters (1,000 feet). For longer distances, consult the manual as frequency roll-off effects may occur.

4. Why does this model have no agency approvals?

Option 00 designates no approvals, making the 74712-06-05-04-00 suitable for non-hazardous area installations only. For hazardous area applications, select models with approval option 01 or other certified variants.

5. What is the mounting torque specification for this transducer?

For the 1/2-20 UNF-3A stud, apply a torque of 5.6 N•m (50 in•lb). For 8-32 threaded studs, use 1.41 N•m (12.5 in•lb). Following these specifications prevents damage and ensures reliable mounting.