Bently Nevada 3300/50-01-02-03-02 Tachometer Module

This tachometer module measures rotational speed from magnetic pickup or proximity sensors. It processes pulse signals for speed indication and overspeed protection. The unit integrates seamlessly into the Bently Nevada 3300 monitoring system.

Technical Specifications

Parameter	Specification
Model Number	3300/50-01-02-03-02
Product Type	Tachometer Module / Speed Monitor
Supply Voltage	24 V DC ±10%
Power Consumption	8 W (maximum)
Input Channels	2 x magnetic pickup or proximity probe
Input Range	100 mV to 100 V peak (AC coupled)
Frequency Range	1 Hz to 20 kHz
Speed Range	1 to 1,000,000 RPM (configurable)
Resolution	12-bit (frequency-to-voltage conversion)
Outputs	2 x 4–20 mA (proportional to speed)
Alarm Relays	3 x Form C (SPDT, 2 A at 30 V DC)
Communication	1 x RS-485 (Modbus RTU)
Sensor Power	–24 V DC (proximity) / no power (magnetic)
Status Indicators	5 x LED (Power, OK, Alarm, Danger, Over-speed)
Mounting	Backplane rack
Dimensions (W x H x D)	26 mm x 223 mm x 175 mm
Weight	0.42 kg

Mechanical Design and Rack Integration

This tachometer module follows the standard 3300 series rack form factor. Its 26 mm width occupies a single slot in the chassis. The unit weighs 0.42 kilograms and includes a robust front panel. All connectors are front-accessible for convenient wiring and inspection.

Power Supply and Electrical Characteristics

The device operates from a 24 V DC supply with a ±10 percent tolerance. It consumes a maximum of 8 watts during normal operation. The module includes reverse polarity protection for the supply input. It also provides –24 V DC excitation for proximity probes when needed.

Sensor Input and Signal Conditioning

Two independent channels accept magnetic pickup or proximity probe inputs. The input range spans from 100 millivolts to 100 volts peak. The frequency response covers from 1 Hz to 20 kHz for versatile speed measurement. The module automatically adjusts gain for optimal signal detection.

Speed Measurement and Conversion

The device measures rotational speed from 1 to 1,000,000 RPM. Users can configure the scaling for various gear tooth counts. The 12-bit frequency-to-voltage conversion delivers reliable speed readings. The module calculates both instantaneous and averaged speed values.

Output and Alarm Functions

Two isolated 4–20 mA outputs transmit speed data to control systems. Users can configure each output with its own scaling parameters. Three Form C relays provide alert, danger, and overspeed protection. These relays handle up to 2 amperes at 30 V DC. The overspeed relay trips when speed exceeds the set threshold.

Communication and Remote Access

An RS-485 port supports Modbus RTU for remote monitoring and configuration. This interface enables integration with plant-wide control networks. Users can read real-time speed and alarm status remotely. The module also stores peak speed values for trend analysis.

Diagnostic Features and Status Indication

Five front-panel LEDs provide clear operational feedback at a glance. The Power LED confirms correct supply voltage application. The OK LED indicates normal sensor operation and module health. Three additional LEDs show alarm, danger, and overspeed conditions. These visual aids simplify troubleshooting during commissioning.

Application Suitability

This tachometer module serves critical rotating equipment across many industries. It works effectively with steam turbines, gas turbines, and large compressors. The device also monitors pumps, blowers, and paper machine drives. Its operating temperature ranges from -20°C to +65°C.