Description
Product Core Brief
- Model: 3500/50M
- Brand: BENTLY NEVADA
- Series: 3500 Machinery Protection System
- Core Function: Determines shaft speed, rotor acceleration, and rotational direction.
- Product Type: 2-Channel Tachometer Monitor
- Key Specs: 2 Channels | +10.0 V to -24.0 V Input | 5.8 W Power
- Condition: New Original (New Surplus)
BENTLY 3500/50M
Product Introduction
BENTLY 3500/50M is a 2-channel tachometer monitor designed for the 3500 Machinery Protection System. It accepts inputs from proximity probes or magnetic sensors to determine precise shaft speed, rotor acceleration, or rotor direction.
The module compares these measurements against user-programmable alarm setpoints to generate alerts. Unlike the 3500/53 which handles electronic overspeed detection, the 3500/50M is strictly for monitoring and provides keyphasor signals to the backplane without requiring a separate keyphasor module.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Module Type | 2-Channel Tachometer Monitor |
| Input Signal Range | +10.0 V to -24.0 V |
| Input Impedance | 20 kΩ (Standard), 40 kΩ (TMR), 7.15 kΩ (Internal Barrier) |
| Output Impedance | 550 Ω |
| Power Consumption | 5.8 W (Typical) |
| Front Panel LEDs | OK, TX/RX, Bypass |
| Supported Functions | Speed Monitor, Setpoint Alarm, Speed Band Alarm |
| Additional Functions | Zero Speed Notification, Rotor Acceleration Alarm, Reverse Rotation Notification |
| Configuration Tool | 3500 Rack Configuration Software |
| Compliance | API 670 |
Quality Control Process (Engineer’s Perspective)
- Incoming Verification: We check source traceability and verify serial numbers against anti-counterfeit databases. Visual inspection confirms no physical damage or connector corrosion.
- Live Functional Test: Power-on self-checks validate basic operation. We run continuous load tests exceeding 24 hours with temperature logging to ensure stability.
- Electrical Parameter Test: Insulation resistance is verified using a 500 V Megger, requiring >10 MΩ. Ground continuity is also strictly checked.
- Firmware Verification: We read and record internal firmware versions. DIP switch and jumper settings are photographed for future reference.
- Final QC & Packaging: The unit is sealed in an anti-static bag. A QC Passed label with the inspection date is applied before shipping.
BENTLY 3500/50M
Replacement Pitfall Guide
❗ Overspeed Protection Limitation: The 3500/50M is strictly a monitoring module and is not used for overspeed protection. If you require certified overspeed trip functionality, you must use the 3500/53 module instead.
❗ Zero Speed Channel Requirement: When configuring this module for zero speed functionality, both channels must be used simultaneously. This effectively reduces the module to a single-channel monitor for that specific application.
❗ Keyphasor Backplane Integration: The 3500/50M can be configured to provide a keyphasor signal directly to the 3500 rack backplane. If utilized this way, you do not need to install a dedicated 3500/25 keyphasor module.
❗ Peak Hold Memory: This module features a peak hold function that stores the highest speed, reverse speed, or reversal count reached. Remember that these stored peaks must be manually reset by the user via the configuration software.
❗ ESD Damage: Use an anti-static mat during installation. Dry environments significantly increase electrostatic discharge risks to sensitive electronics.
Keep these in mind and you’ll cut 90% of rework time.
Compatibility Matrix & Benchmarks
- 3500/50M → 3500/53 : Incompatible — Tachometer Monitor vs. Electronic Overspeed Detection
- 3500/50M → 3500/46M : Needs Adaptation — Standard Tachometer vs. Low-Speed Hydro Turbine Response
- 3500/50M → 3500/25 : Companion — Can replace dedicated Keyphasor module via backplane signal
- Scan Cycle: < 1 ms (simulated load, 2 I/O points)
- Comms Throughput: Backplane interface (Modbus TCP via 3500/22M TDI)
Need the matching 3300 XL proximity probe or magnetic sensor for this tachometer? I can verify the exact signal conditioning and zero-speed pairing requirements for your turbine or compressor application.
