Description
Providing high-accuracy phase reference and rotational speed measurements for machinery protection, the Bently Nevada 3500/25-01-01-CN is a half-height, dual-channel module designed for the 3500 Machinery Protection System. This specific model features a single half-height 2-channel Keyphasor card paired with an I/O module configured for internal terminations. The hardware processes input signals from proximity probes or magnetic pickups, converting them into digital phase reference pulses used by other monitoring modules in the rack. Approved under country-specific standards (CN designation), this industrial-grade module ensures reliable operation within critical diagnostic architectures.
Features
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Two-Channel Processing: Dual independent channels process phase reference signals simultaneously.
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Internal Terminations: Integrated wiring terminals streamline panel installation, eliminating the requirement for external termination blocks.
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Flexible Sensor Compatibility: Accepts inputs directly from passive magnetic pickups, multi-event wheels, and proximity transducer systems.
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Rack Integration: Fits into half-height slots of standard 3500 series chassis, maximizing slot density.
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CN Approvals: Certified under regional country-specific electrical and safety standards.
Applications
- Rotational speed tracking on heavy utility steam and gas turbines.
- Phase-angle determination for multi-stage centrifugal compressors.
- Vibration analysis and balancing of high-speed industrial fans and blowers.
- Hydroelectric generator shaft alignment and orbit plotting.
Ordering Information
| Option Code |
Configuration Detail |
| 3500/25 |
Enhanced Keyphasor Module |
| -01 |
Single half-height 2-channel Keyphasor card (order for 2 channels) |
| -01 |
I/O Module with Internal Terminations |
| -CN |
Country Specific Approvals (China / Regional Standards) |
Technical Specifications
| Parameter |
Value / Requirement |
| Manufacturer |
Bently Nevada |
| Series |
3500 Machinery Protection System |
| Input Channels |
2 differential or single-ended channels |
| Input Signal Range |
+0.8 V to -26.0 V (Non-contact sensors) or 8 V peak-to-peak (Magnetic pickups) |
| Input Impedance |
10 kohm minimum |
| Power Consumption |
3.2 Watts typical |
| Signal-to-Noise Ratio |
Minimum 20 dB dynamic range |
| Operating Temperature Range |
-30 degC to +65 degC (-22 degF to +149 degF) |
| Country of Origin |
United States (Made in U.S.A.) |
| Shipping Weight (Calculated) |
2.0 kg (including module, internal terminations I/O card, and protective packaging) |
Connections and Interfaces
| Terminal / Pin No. |
Signal Assignment |
Description |
| 1 |
KPH 1 + |
Keyphasor Channel 1 Non-Inverting Signal Input |
| 2 |
KPH 1 - |
Keyphasor Channel 1 Inverting / Common Return |
| 3 |
KPH 1 OUT |
Transducer Power (-24 VDC Supply for Proximitor) |
| 4 |
KPH 2 + |
Keyphasor Channel 2 Non-Inverting Signal Input |
| 5 |
KPH 2 - |
Keyphasor Channel 2 Inverting / Common Return |
| 6 |
KPH 2 OUT |
Transducer Power (-24 VDC Supply for Proximitor) |
| 7 |
SHIELD |
Dedicated cable shield ground point (tied to chassis ground) |
Empirical Engineering Insights
Alternative Models & Compatibility
The "Enhanced" 3500/25 module directly replaces legacy non-enhanced 3500/25 modules. However, firmware compatibility must be verified prior to hot-swapping: your 3500 Rack Configuration Software must be upgraded to version 3.3 or higher to configure the advanced dynamic hysteresis options. Do not attempt to run a non-enhanced card and an enhanced card as a redundant pair in the same slot space; both cards must share the same hardware revision level to guarantee system synchronization.
Application Pitfalls & Engineering Notes
When configuring magnetic pickups, field engineers should note that the output signal drops significantly at low RPM. If the machine operates below 100 RPM, standard passive magnetic pickups may not generate sufficient amplitude to cross the threshold, leading to "Keyphasor Fault" indications. In these scenarios, use active proximity sensors which maintain constant voltage outputs down to zero speed.
Commissioning & Wiring Tips
To prevent electromagnetic interference (EMI) from neighboring power cables and variable frequency drives (VFDs), ensure Keyphasor wiring is routed via dedicated, shielded twisted-pair (STP) lines. The shield should only be grounded at the 3500 chassis ground terminal on the I/O card; the sensor-end shield must be left floating and insulated to eliminate parasitic ground loops.
Installation Guidelines
CRITICAL WARNING
Prior to removing or installing any 3500/25 module, ensure the rack is placed in a bypassed or safe state. Improper hot-swapping in active protection racks can trigger false machinery trip signals. Verify field wiring insulation to prevent accidental shorting of the -24 VDC transducer power lines to the chassis ground.
1
Inspect the module backplane and gold connector pins for debris or misalignment before insertion.
2
Align the half-height module card with the upper or lower guide rails in the selected slot location.
3
Slide the module gently but firmly straight back into the rack until the ejector tabs lock cleanly.
4
Secure the front-panel mounting screws to ensure proper chassis grounding and thermal contact.
5
Upload and verify configuration parameters via the Bently Nevada 3500 Rack Configuration software.