PR9268/301-100 Electrodynamic Velocity Sensor | Emerson EPRO

Configured for seismic vibration acquisition in rotating machinery, the Emerson EPRO PR9268/301-100 (PR9268/301-100) Electrodynamic Velocity Sensor provides direct electrical execution of velocity-based vibration monitoring.

Hardware Specifications

Mechanical Monitoring and TSI Characteristics

The PR9268/301-100 operates on an electrodynamic principle, where an internal mass-spring system converts seismic mechanical motion into a proportional voltage output. Accurate rotor dynamics analysis requires the sensor to be mounted within its calibrated orientation—specifically, horizontal with a tolerance of +/- 10 deg for this variant. Operators must verify proper cabling to the monitoring system, as high-frequency coil induction is susceptible to electromagnetic interference. To maintain signal integrity, ensure the sensor body is mechanically coupled to the machine casing to minimize high-frequency attenuation, and perform periodic impedance checks to confirm the coil circuit continuity remains within specified limits.

Frequently Asked Questions

Q: Does the sensor require an external power supply to function?

A: No. The PR9268/301-100 is a passive electrodynamic device that generates its own output signal based on seismic movement. It does not require supply voltage, but must be connected to a compatible signal conditioner with the correct input impedance.

Q: What is the significance of the natural frequency rating?

A: The natural frequency of 4.5 Hz +/- 0.75 Hz defines the lower limit of the sensor's linear measurement range. Operation below this natural frequency will result in phase shift and non-linear amplitude response, making it unsuitable for low-frequency structural vibration analysis.

Field Installation Guidelines

1. Secure the sensor to a flat, machined surface on the bearing housing or casing using a heavy-duty mounting stud to ensure rigid high-frequency transmission.
2. Verify the mounting orientation is horizontal; exceeding the +/- 10 deg tolerance will introduce gravitational bias to the internal spring, altering the natural frequency and damping characteristics.
3. Terminate signal leads at the signal conditioner input using shielded twisted-pair cabling; connect the shield to a common instrument ground to minimize 50/60 Hz line noise.
4. Confirm the cable length does not introduce excessive capacitive loading, which can attenuate the high-frequency response (up to 1000 Hz).
5. Conduct a physical tap test during commissioning to verify a positive output signal, confirming polarity and circuit integrity before the machinery is brought to full operating speed.