Bently Nevada 3500/50M Tachometer Module

Overview

The Bently Nevada 3500/50M is a dual-channel tachometer module designed for precise shaft speed measurement in industrial machinery. It accepts signals from proximity probes or magnetic pickups to monitor shaft rotation, rotor acceleration, and rotation direction. The module triggers alarms when user-defined thresholds are exceeded, ensuring safe and reliable machine operation. Additionally, it can supply conditioned Keyphasor signals to the 3500 rack, eliminating the need for a separate Keyphasor module.

Key Features

Monitors shaft speed with configurable setpoint alarms for safety and reliability.
Provides reverse rotation and zero-speed notifications, improving machine protection.
Stores peak speed, reverse speed, or number of reverse rotations for diagnostic purposes.
Configurable using 3500 Rack Configuration software for custom monitoring setups.
Outputs include front panel LEDs, buffered transducer outputs, and 4–20 mA recorder signals.

Technical Specifications

Parameter	Specification
Model Number	3500/50M
Series	3500 Series Monitoring
Input Signal Range	+10 V to -24 V
Input Impedance	20 kΩ (Standard), 40 kΩ (TMR), 7.15 kΩ (Internal Barrier)
Power Consumption	5.8 W (typical)
Output Signals	Front panel LEDs, buffered transducer outputs, 4–20 mA recorder
Dimensions	241.3 mm x 24.4 mm x 241.8 mm (9.50 in x 0.96 in x 9.52 in)
Weight	0.82 kg (1.8 lb)
Operating Temperature	-40°C to +70°C
Speed Measurement Method	Proximity probes or magnetic pickups
Accuracy	<100 rpm: ±0.1 rpm; 100–10,000 rpm: ±1 rpm; >10,000 rpm: ±0.01%

Applications

Monitors shaft speed for turbines, compressors, and generators in industrial systems.
Supports 3500 Series vibration monitoring racks with integrated Keyphasor signal output.
Ideal for process industries requiring precise rotor acceleration and reverse rotation detection.