Description

The Bently Nevada* Stator Insulation Monitoring System uses state of the art technologies to measure the leakage current of motors sized up to 7.5 kV and 1000 Amps. The measurements are made while the motor is online and the system processes the measured data in real time to determine the condition of the stator insulation in the motor. The system consists of a 9-channel 3500/82 monitor that accepts inputs from the 350820 High Sensitivity Current Transformer (HSCT), 350822 High Voltage Sensors (HVS), and 4-20 mA process signals corresponding to motor temperature measurements. The 3500/82 processed data and results can be displayed on the 3500/94 Display. The user can configure the 3500/82 using the 3500 Rack Configuration Software to perform the following functions:

Display instantaneous stator leakage current on each phase of the motor.

Display compensated dissipation factor and change in dissipation factor from a given reference point.

Display motor stator temperature and average temperature.

Display line voltage and frequency data values.

Retrieve historic data stored on board the monitor for data analysis.

Set alarm levels for annunciation.

Configure the temperature range and time period for learn and extend modes for temperature learning, and view the current learning state.

View the number of temperature samples, vs. operating temperatures, that builds the learning curve used for temperature compensation.

Note: The 3500/82 monitor should not be used for machine protection.

The 3500/82 can accept 3 HSCT, 3 HVS, and 3 4-20mA process inputs from stator RTD temperature measurements. Since the interface modules are capable of driving long field cables, the monitor can be situated in a control or instrumentation room up to 330 meters (1,000 feet) away from the motor or the interface modules.

The 3500/82 is featured with measurement trending by comparing the current measurements to any historical data taken in the last 10 years (if the historical data is available). The time window for comparison is user configurable.

The 3500/82 monitor has eight buffered outputs for diagnostic purposes, 3 each HVS and HSCT values for each of those corresponding inputs, an average temperature from the temperature inputs, and a synchronization phase pulse reference signal.