SHINKAWA VM-5C Shaft Eccentricity Monitor

The SHINKAWA VM-5C SST-2194-001-P001G is a specialized shaft eccentricity monitor designed for the VM-5 series machinery protection system. This module measures rotor bow and shaft runout during turbine startup and coast-down, providing critical data for safe equipment operation and prevention of rub damage during thermal transient conditions.

Technical Specifications

The module delivers high measurement accuracy with ±0.5% FS at 25°C, maintaining reliable performance across the 0°C to 65°C operating range. The measurement range of 0-500 μm peak-to-peak accommodates typical turbine eccentricity requirements, with configurable alarm setpoints for alert and danger conditions. Dual analog outputs provide 4-20 mA and 1-5 V DC signals proportional to measured eccentricity.

• Input Sensor: FK series eddy current probe

• Measurement Range: 0-500 μm peak-to-peak

• Measurement Accuracy: ±0.5% FS (25°C)

• Analog Outputs: 1-5 V DC (100 Ω), 4-20 mA DC (500 Ω max load)

• Alarm Outputs: 4 configurable relay contacts (danger/alert)

• Self-Diagnostics: Module fault, sensor break, power supply monitoring

• Communication Protocol: Modbus RTU

• Isolation: 2500 Vrms input-to-output isolation

Alarm and Protection Functions

The VM-5C provides independent programmable alert and danger alarm setpoints, allowing operators to establish appropriate thresholds based on manufacturer specifications or operational experience. Configurable time delays prevent nuisance tripping during transient conditions, while latching and non-latching options accommodate different alarm response philosophies.

Startup Monitoring Application

Shaft eccentricity monitoring is critical during turbine startup when the rotor may experience uneven thermal expansion. High eccentricity indicates potential rub conditions that could cause significant damage if the turbine is accelerated to operating speed. The VM-5C provides continuous monitoring during this critical period, enabling operators to verify safe conditions before proceeding with startup sequencing.