Condition Monitoring of High-Voltage Motors

Ensuring Safety with Temperature Transmitters containing High Electrical Isolation

Having an active predictive maintenance campaign in place for large rotating equipment can be a key strategy for maximizing process uptime. With the advent of Industry 4.0, condition monitoring programs that employ the collection and analysis of temperature and vibration data have become more and more widespread across a number of industries.
Some of this rotating equipment, such as motors and generators, find themselves operating in particularly high-voltage environments. Not only does this strengthen the case for condition monitoring, in that the failure of these systems could present an unsafe scenario, but it also creates the need for the monitoring itself to be performed safely.
This can prove especially difficult with temperature, as embedded sensors within the rotating equipment can find themselves in direct contact with high-voltage elements, creating a potentially dangerous situation.

The Challenge:
A company in the Chemical Processing Industry brought a problem to Knick’s attention, in an effort to find a solution for their network of plants. What they found was that after years of operation, insulation defects in their slot mounted temperature sensors installed in high-voltage motors were exposing downstream systems and personnel to dangerous voltage levels. This created the potential for a serious hazard that needed to be eliminated.

The Solution:
The P44000 series was developed by Knick to accurately measure temperature from Pt100 RTDs in high-voltage environments, up to 11kV. The P44000 converts the RTD signal to a standard 4-20mA output that can be easily read by the majority of control systems. This measurement and conversion is performed across a high galvanic isolation barrier, where the input, output and power supply channels are safely protected against a potential transfer of dangerous voltage.