PR9268/20 | Epro | Electrodynamic Velocity Sensor Probe

Configured for seismic vibration acquisition in rotating machinery, the Epro PR9268/20 (PR9268/20) Electrodynamic Velocity Sensor Probe provides direct electrical execution of velocity-based vibration monitoring.

Hardware Specifications

Mechanical Monitoring and TSI Characteristics

The PR9268/20 employs a magnetic induction principle to generate an analog velocity signal, necessitating precise mounting to ensure the internal mass-spring system maintains its 4.5 Hz natural frequency. Deviations from the specified vertical or horizontal orientation will introduce gravitational bias and degrade measurement linearity. When integrated into TSI racks, signal integrity is managed through careful impedance matching with the signal conditioner to account for the 1875 Ohm coil resistance. To ensure rotor dynamics fidelity, operators must verify that the machine casing vibration does not exceed the 10 g continuous acceleration limit, and employ cross-talk suppression by isolating the sensor from adjacent high-energy magnetic fields or other inductive transducers.

Frequently Asked Questions

Q: Does this sensor require an external DC power supply?

A: No. The PR9268/20 is a passive electrodynamic transducer that generates an analog signal via electromagnetic induction. It requires no excitation voltage; however, the connected monitoring system input must have high impedance (nominally 100 kOhm) to maintain the specified sensitivity.

Q: How should the transducer be tested during commissioning?

A: A physical bump test or low-frequency shaker table verification is required to confirm the output signal matches the 28.5 mV/mm/s sensitivity. Ensure the signal polarity is consistent with the TSI channel configuration to prevent phase inversion during vibration processing.

Field Installation Guidelines

1. Mount the sensor housing firmly to the bearing housing or machinery casing using the specified stud or bracket; ensure the mating surface is clean and flat to guarantee high-frequency coupling.
2. Verify the orientation of the transducer aligns with the intended measurement axis; incorrect orientation will shift the natural frequency and distort amplitude readings.
3. Terminate the cable using a shielded connection, ensuring the cable shield is grounded at the signal conditioner input only to prevent ground loop noise.
4. Route the sensor cable away from high-power AC motor leads or VFD cabling to minimize electromagnetic interference (EMI).
5. Ensure the ingress protection (IP55/IP65) is maintained by properly securing the connector or cable gland; avoid exposing the PTFE cable insulation to aggressive solvents or excessive mechanical abrasion.