Bently Nevada 190501 Velomitor CT Velocity Transducer

Overview

The Bently Nevada 190501 Velomitor CT Velocity Transducer is a low-frequency version of the standard Velomitor piezo-velocity sensor, designed specifically to measure casing vibration velocity on cooling tower fans and air-cooled heat exchanger (fin-fan) assemblies. These large, slow fans typically turn at 100 to 300 rpm, and the Bently Nevada 190501 is rated for fans operating at or above 90 rpm, a speed range where ordinary velocity sensors lose sensitivity. The transducer captures vibration at the fan running speed as well as the higher frequencies generated by the fan motor and the speed reducer, so a single sensor covers the whole drive train.

Seven Star LLC supplies the Bently Nevada 190501 on request to refineries, gas plants, power stations and district cooling operators in the Sultanate of Oman and the wider GCC, with engineering support in Muscat. The Bently Nevada 190501 datasheet (document 141636) is attached to this page, and our instrumentation team can help select the correct mounting stud, connection option, hazardous area approval and interconnect cable for each fan.

Measurement Principle

Inside the Bently Nevada 190501 a piezoelectric sensing element produces a charge proportional to casing acceleration, and built-in electronics integrate that signal into a voltage proportional to vibration velocity. The output sensitivity is 3.94 mV/mm/s (100 mV/in/s) ±5%, with a frequency response of 1.5 Hz to 1.0 kHz (90 to 60,000 cpm) within ±3.0 dB and 3.0 Hz to 900 Hz within ±1.0 dB. That low corner frequency is what separates the CT model from a general-purpose velocity sensor: a fan turning at 120 rpm produces a 1X vibration component at only 2 Hz, which the Bently Nevada 190501 can still resolve with a typical broadband noise floor of 0.229 mm/s (0.009 in/s) peak between 1.5 Hz and 1 kHz.

The velocity operating range is 63.5 mm/s (2.5 in/s) peak with amplitude linearity of ±2% across that range, transverse response below 5% of the axial sensitivity and a mounted resonant frequency of at least 9 kHz when stud mounted. Because the sensor is solid-state, there is no moving coil or spring to wear out, and it can be mounted in any orientation. In practice, this gives cooling tower operators an early indication of blade unbalance, looseness, misalignment, gearbox wear and motor bearing problems before they develop into a blade failure or a fan that throws a blade through the fill or the fan stack.

Engineering Design of the Bently Nevada 190501

The Bently Nevada 190501 is housed in a 316L stainless steel case with a top-exit 2-pin MIL-C-5015 connector, also in 316L stainless steel. It stands 82 mm (3.2 in) high on a 33 mm (1.3 in) diameter mounting surface, has a 31.8 mm (1.25 in) hex for installation and weighs less than 297 g (10.5 oz). The recommended mounting torque is 4.5 N·m ±0.6 N·m (40 in·lbf ±5 in·lbf), and the case top has a 1/2-inch NPT thread for the optional 128608-02 conduit adapter so that the cable can run inside flexible conduit or Teflon-coated stainless steel armor in the wet, corrosive environment of a cooling tower.

Electrically, the Bently Nevada 190501 runs on 10 to 24 V dc, its internal electronics are isolated from the case, and the output bias is 10.1 V dc ±1.0 V dc on Pin A referenced to Pin B. The output impedance is typically below 400 Ω, and the datasheet allows 305 m (1,000 ft) of 02173006 cable with no degradation of signal. Operating temperature is −40 °C to +85 °C, shock survivability is 5,000 g peak, and the sensor tolerates 100% condensing humidity when not submerged. The order code 190501-AA-BB-CC selects mounting hardware (from no stud through standard, adhesive, plate and quick disconnect studs), connection type (MIL-C-5015 interface or a unit with an included 32 ft cable) and agency approvals.

Key Features

The Bently Nevada 190501 is built around the needs of slow-speed fan monitoring. Its main capabilities include:

• Low-frequency velocity response from 1.5 Hz (±3 dB), suited to cooling tower and air-cooled heat exchanger fans running at 90 rpm and above.
• Sensitivity of 3.94 mV/mm/s (100 mV/in/s) ±5% with a velocity range of 63.5 mm/s (2.5 in/s) peak and ±2% linearity.
• Low typical noise floor of 0.229 mm/s (0.009 in/s) peak between 1.5 Hz and 1 kHz, so small changes at 1X running speed remain visible.
• 316L stainless steel case and 2-pin MIL-C-5015 connector for wet, humid and corrosive fan deck environments.
• Internal electronics isolated from the case, which helps avoid ground loops on long cable runs to the monitoring system.
• Cable runs of up to 305 m (1,000 ft) to the monitor with no degradation of signal.
• Wide choice of mounting studs, adhesive bases and a quick disconnect option that lets the sensor be removed without turning the cable.
• Hazardous area approval options including ATEX/IECEx Ex ia IIC T3 Ga and Class I, Division 1 intrinsically safe ratings.

Industrial Applications

Air-cooled heat exchangers are everywhere in Gulf process plants because water is scarce and ambient temperatures are high, and every fin-fan bay is a candidate for the Bently Nevada 190501. Typical installations in Oman include air coolers on crude units and gas compression trains, wet and hybrid cooling towers at power and desalination plants in Sohar and Barka, district cooling plants in Muscat, and cooling towers at petrochemical and fertilizer sites in Sur, Duqm and Salalah. Mounted on the speed reducer or on a bracket near the fan, the Bently Nevada 190501 gives a continuous velocity signal that can trip the fan motor on high vibration and warn the maintenance team of unbalance from blade fouling or a loose hub.

The transducer can feed a machinery protection rack such as the Bently Nevada 3500 system, a standalone monitor or a 2-wire transmitter for DCS input. For general-purpose velocity points on pumps and motors, compare the Bently Nevada 330500 Velomitor piezo-velocity sensor and the earlier Bently Nevada 9200 seismic velocity transducer; where the plant needs a 4–20 mA signal, the Bently Nevada 990 2-wire vibration transmitter is another option in our catalog. Seven Star LLC helps reliability engineers in the GCC choose between these sensors, plan spare parts and size cables for each Bently Nevada 190501 point.

Technical Specifications

Key parameters of the Bently Nevada 190501, taken from manufacturer datasheet 141636 Rev. AF (specified at +20 to +30 °C and 100 Hz unless noted):

Request a Quote for Bently Nevada 190501

To request a quotation for the Bently Nevada 190501, check current availability and lead time or download the manufacturer datasheet from the document tab on this page, send the full order code or the fan details, mounting stud thread, cable length and hazardous area classification to the Seven Star LLC instrumentation team. We supply the Bently Nevada 190501 and its studs, conduit adapters and interconnect cables to customers in Oman and the GCC.

Related Bently Nevada sensor from Seven Star LLC: Bently Nevada 330400 accelerometer.