Configured for low-frequency casing vibration velocity measurements on cooling towers and air-cooled heat-exchanger fan assemblies, the Bently Nevada 190501-02-99-00 (190501 Velocity Transducer) provides direct physical/electrical execution of dynamic vibration monitoring. This piezo-velocity sensor translates mechanical casing acceleration into a proportional analog velocity output signal for structural and machine casing analysis.

Part Number Configuration Details

The part number 190501-02-99-00 represents a specific hardware configuration defined by the following options:

• 190501: Base model designation for the Velomitor CT (Cooling Tower) Velocity Transducer.
• -02: Mounting Hardware Option, specifying a 3/8-in 24 to 1/2-in 20 mounting stud.
• -99: Connection Option, designating a unit supplied with an integrated 32-foot (approx. 9.75 meters) cable.
• -00: Agency Approval Option, indicating no hazardous area agency approvals are certified for this specific build.

Hardware Specifications

Rotor Dynamics & Low-Frequency TSI Integration

Operating in cooling tower and heat-exchanger fan environments, the 190501-02-99-00 is engineered to capture low-speed rotor dynamics and casing vibrations. In Turbomachinery Instrumentation (TSI) setups, low-frequency fan rotation (typically 100 to 300 RPM) creates measurement challenges for standard piezo-velocity sensors due to rolling-element noise and poor low-end signal-to-noise ratios.

To overcome this, the Velomitor CT utilizes specialized internal integration electronics that filter high-frequency noise while preserving phase and amplitude integrity down to 1.5 Hz (90 RPM). When integrating this transducer into a continuous machinery protection system like the Bently Nevada 3500/42M monitor, correct configuration of the channel sensor type is mandatory. The monitor must be programmed to match the 3.94 mV/mm/s scale factor to ensure accurate velocity tracking and to prevent false NOT OK or system fault status alerts caused by bias voltage drift.

Shipping Package Contents

• 1 x Bently Nevada 190501-02-99-00 Velomitor CT Velocity Transducer
• 1 x Integrated 32-foot (approx. 9.75 meters) connection cable
• 1 x Mounting stud (3/8-in 24 to 1/2-in 20 thread size)

Installation and Cable Routing Guidelines

• Mounting Surface Preparation

  The sensor mounting surface must be flat, smooth, and clean to ensure solid mechanical coupling. Prepare a machined surface with a diameter of at least 30 mm to accommodate the sensor base.

• Thread Torque Specification

  Mount the transducer to the prepared surface using the provided 3/8-in 24 to 1/2-in 20 mounting stud. Tighten the sensor body to the recommended installation torque of 13.5 N m (10 ft lb) to prevent signal loss from mechanical looseness.

• Cable Routing and Protection

  Because this unit features an integrated 32-foot cable, ensure the cable is secured with conduit or cable trays over its entire run. Avoid routing the transducer cable parallel to high-voltage AC lines to prevent electromagnetic coupling and noise.

• Shield Grounding Method

  The integrated cable shield must be terminated at the monitor end (TSI common ground) only. Do not ground the shield at the transducer end; this prevents ground loops that introduce electrical interference into the vibration signal.

Frequently Asked Questions

• What is the minimum operating speed of machinery that this transducer can monitor?

  The sensor is designed to measure vibration on cooling towers and fan assemblies operating at or above 90 RPM (1.5 Hz frequency).

• Can the integrated 32-foot cable on this unit be cut to a shorter length?

  Yes, the cable can be shortened. This is a constant-current, low-impedance velocity transducer, so shortening the cable does not affect the calibration scale factor.

• Is this velocity sensor suitable for permanent submersion in water?

  No. While the 316L stainless steel housing resists 100% condensing humidity, the sensor is not rated for continuous underwater submersion.

• Does this specific model (190501-02-99-00) carry ATEX explosion-proof certifications?

  No. The "-00" suffix in the ordering code specifies the "No Approvals" option, meaning this unit is not certified for hazardous or explosive areas.

• How is the transducer powered in a standard industrial setup?

  The transducer is loop-powered by the machinery protection monitor, which supplies a constant current of 2 to 10 mA down the signal lines.

• What happens to the vibration readings if the mounting torque is too low?

  Low mounting torque creates high-frequency resonance at the mounting interface, which can cause reading distortion and attenuate the true low-frequency vibration signals.

• Can this sensor be mounted horizontally on the machine casing?

  Yes, the piezo-velocity element inside the transducer is omnidirectional and operates accurately in both vertical and horizontal mounting orientations.

• How does temperature fluctuation affect the transducer's sensitivity?

  The sensitivity varies typically between -8% and +5% across its entire rated operating temperature range of -40 to +85 deg C.