Description
Meta Description
Get the technical breakdown of the Bently Nevada 3500/25-02-01-CN Enhanced Keyphasor module. Read about the 4-channel configuration and internal terminations.
Main Body
When monitoring multi-shaft turbomachinery trains, losing your phase reference cards can completely compromise your machinery diagnostics. The Bently Nevada 3500/25-02-01-CN is an Enhanced Keyphasor Module designed for the 3500 Machinery Protection System. This specific model configuration receives raw pulse signals from proximity probes or magnetic pickups, processing them to calculate shaft rotational speed and critical phase angle data.
Technical Specifications Snapshot
| Parameter | Value |
| Model Number | 3500/25-02-01-CN |
| Module Type | Enhanced Keyphasor Module |
| Channel Count (02) | Two half-height cards (Configured for up to 4 channels total) |
| I/O Type (01) | I/O Module with Internal Terminations (125808-01 rear card) |
| Agency Approvals (CN) | ATEX/IECEx and local NEPSI certifications for hazardous areas |
| Input Signal Range | +0.8 V to -21.0 V DC (Standard non-isolated transducers) |
| Frequency Range | 1 to 1,200,000 cpm (0.017 Hz to 20 kHz) |
| Power Consumption | 3.2 W typical |
| Condition | New Original or Refurbished (tested) |
By selecting the -02 option, this package provides two half-height, 2-channel cards, permitting up to four independent Keyphasor channels within a single rack slot. The -01 option pairs these cards with the 125808-01 rear I/O module, which features integrated, removable screw terminals for direct field connection.
Do you have isolated magnetic pickups that share signals directly with legacy Distributed Control Systems (DCS)? This configuration is not recommended for setups requiring parallel, isolated signal splitting. The non-isolated -01 internal termination I/O module can experience electrical interference or impedance loading if the raw signal is jumped to external control systems. For those scenarios, the isolated I/O variants (-04 or -05) are required.
Well, technically, the module is rated for speed tracking up to 20 kHz, but highly accurate phase measurements rely heavily on setting correct trigger threshold voltages. If the target notch on your turbine shaft has worn down, you must adjust the hysteresis values in your 3500 Rack Configuration software to prevent erratic tracking. Keeping a spare 3500/25-02-01-CN module on your shelf is an excellent insurance policy against long factory lead times during unplanned shutdowns.
