Description
Product Core Brief
- Model: 133442‑01
- Brand: BENTLY
- Series: 3500 Machinery Protection System (3500/50 Tachometer Module rear‑plane assembly)
- Core Function: This is the rear‑plane I/O circuit board for the 3500/50 tachometer module. It interfaces shaft speed sensor inputs, routes signals to the front‑plane processing board, and communicates measurement data across the 3500 rack backplane. It monitors shaft RPM, rotor acceleration, and rotation direction for rotating‑machinery condition monitoring.
- Product Type: Tachometer Rear‑Plane I/O Board
- Key Specs: 2 input channels | Full‑height slot | Works with proximity probes and magnetic pickups; mates with front panel 288062‑02
Note: OEM discontinued; available as new surplus and field‑tested used stock.
BENTLY 133442‑01
Key Technical Specifications
- Input Channels: 2 independent tachometer input channels
- Supported Sensors: 3300‑series eddy‑current proximity probes, magnetic pickups
- Input Frequency Range: 3.3 Hz to 20 kHz
- RPM Measurement Range: 0‑99999 RPM
- Backplane Power Draw: 230 mA @ +24 VDC
- Form Factor: Full‑height rear‑plane board for 3500‑series rack; must pair with matching 3500/50 front‑panel assembly
- Measurement Functions: Shaft speed, rotor acceleration, reverse rotation detection, zero‑speed alarm
- Buffered Keyphasor output to rack backplane for other monitor modules
- Operating Temperature: 0 °C to +65 °C
- Weight: 0.39 kg
- Dimensions: 241 mm × 114 mm × 25 mm
- Humidity: 5‑95 % non‑condensing
- Compliance: API 670 for machinery‑monitoring applications
Product Introduction
This rear‑plane circuit board forms the signal‑input half of the 3500/50 tachometer module. It receives raw pulse signals from field‑mounted speed sensors, provides signal conditioning, and passes conditioned signals to the mating front‑plane processing board. The front‑plane executes speed‑related calculations and alarm logic, while this rear‑plane handles all field‑wiring termination and physical signal interfacing.
The combined 3500/50 assembly can distribute buffered keyphasor timing signals across the rack backplane, removing the requirement for a separate dedicated keyphasor module in many installations. It is widely deployed on turbines, compressors, pumps, and gearboxes for non‑safety‑critical speed monitoring. It is not designed for overspeed trip safety voting functions.
BENTLY 133442‑01
QA & Testing SOP
- Incoming Inspection: Match part number and serial number against OEM documentation. Inspect edge connectors, field‑signal terminals, and PCB traces for wear, burn marks, or counterfeit marking defects. Confirm physical compatibility with 288062‑02 front‑panel assembly. Log serial numbers for traceability.
- Live Testing: Mate with matching genuine 3500/50 front‑panel, seat inside valid 3500 rack, apply rated backplane power. Establish comms handshake with rack configuration software. Inject variable‑frequency pulse inputs to each channel, validate RPM readings, acceleration and reverse‑rotation detection over continuous 24‑hour load test.
- Electrical Testing: Use Fluke 115 and insulation tester. Verify insulation resistance >10 MΩ between signal circuits and chassis ground. Confirm chassis‑to‑rack‑earth continuity.
- Firmware/Config Backup: Record exact firmware revision from the paired front‑panel assembly. Capture screenshots of channel parameters, alarm setpoints before reset. Photograph board connector layout for reference records.
- Final QC & Packaging: Place unit inside anti‑static shielding bag. Apply printed QC pass tag with test‑date stamp. Pack with shock‑absorbent foam for transit.
Installation Pitfalls & Guide
❗ Mating‑Board Mismatch: 133442‑01 rear‑plane must pair with its matching 3500/50 front‑panel (288062‑02). Mismatched front‑rear combinations produce no valid measurements or intermittent channel failures. Photograph existing assembly before removal.❗ Firmware Rev Mismatch: Mismatched rack firmware and tachometer‑module firmware creates incorrect RPM readings or missing keyphasor timing signals. Confirm firmware compatibility before commissioning.❗ Slot Location Error: This hardware requires a full‑height rack slot. Partial seating breaks backplane communication. Photograph old hardware layout prior to removal.❗ Wiring Incompatibilities: Proximity‑probe and magnetic‑pickup field wiring require different termination practices. Cross‑reference OEM datasheet before landing field wiring; mis‑termination yields zero speed pulses.❗ Power Draw Changes: Adding this full‑height assembly increases total rack backplane load. Calculate aggregate slot‑by‑slot current consumption to avoid overloading rack power supplies.❗ ESD Dangers: Unprotected handling can destroy high‑speed pulse‑conditioning circuits. Field cases show ESD‑damaged spare units valued over $2000 before power‑on. Always use grounded ESD wrist straps.
4‑step replacement guide1. Pre‑install: De‑energize rack power, don ESD wrist strap. Validate rear‑plane to front‑panel compatibility and rack‑firmware revision. Document speed‑channel configuration and field‑wiring assignments.2. Removal: Release front‑panel latch, extract the complete 3500/50 assembly, separate front‑panel and faulty 133442‑01 rear‑plane.3. Install: Attach the replacement 133442‑01 rear‑plane to the existing front‑panel assembly. Insert the complete combined unit firmly into full‑height rack slot until latch fully engages. Reconnect field wiring per datasheet pinout.4. Power‑on Test: Restore rack power, confirm backplane communication. Inject simulated shaft‑speed pulses, validate RPM, acceleration and reverse‑rotation detection. Verify buffered keyphasor signal output across rack backplane.
FAQ
Q: Does this unit support hot‑swap operation?A: No. It draws power directly from the main system backplane. Live removal creates voltage transients that can corrupt adjacent monitoring cards or damage backplane traces. Full rack power shutdown is mandatory.
Q: Can I use 133442‑01 for safety‑critical overspeed trip protection?A: No. This is part of the standard 3500/50 tachometer for condition‑monitoring only. For overspeed trip‑voting applications use the dedicated 3500/53 module (133396‑01).
Q: What happens when stored configuration is lost after power‑cycle?A: All speed‑channel setpoints live in volatile memory on the front‑panel board. Power loss erases custom parameters. Reload rack configuration after power restoration.
Q: Is brand‑new factory stock available?A: Original OEM manufacturing has ceased. Available stock comes from new‑surplus or field‑tested used inventory. Lead‑times shift with lot availability.
Q: What warranty applies to surplus stock?A: Third‑party inventory carries limited‑time functional warranty covering hardware defects. It excludes damage caused by site‑side over‑voltage events, mis‑wiring, or incorrect configuration. OEM factory warranty is no longer offered.
Q: Can I swap only the rear‑plane board without replacing the front‑panel?A: Mechanically yes, but you must verify part‑number compatibility between front‑panel and rear‑plane. Always perform full‑channel functional validation after replacement.
Q: Can 3500/53 module parts serve as drop‑in replacements?A: Physical form factor matches, but signal‑processing hardware and safety‑trip logic differ. Direct substitution is not allowed.
