Lately, more and more of our readers have been inquiring about RTDs, or resistance temperature detectors. A common type of RTD is the PT100. This type of device has begun appearing more frequently on bid specifications and product requirements, and as a result, our Submersible Service Hotline has seen a surge of requests for information. What is it? What does it do? Does Franklin Electric supply it? To get the word out most effectively, we are therefore giving this topic special attention in this issue of Franklin AID.
Simply put, the PT100 is a platinum wire precision resistor that is placed in a special stud bolt for the Franklin Electric motor. Separate control leads must then run to a surface control unit to monitor temperature. The PT100 can then be used to detect insufficient cooling to the motor and thus contribute to its protection. Note, however, that this sensor does not replace the required electrical overload protection that is specified in the motor installation manual. All three power supply legs of a three-phase submersible motor still require an ambient compensated overload with quick-trip characteristics (NEMA Class 10) or a Franklin Electric Subtrol-Plus premium motor protection system. Continue reading