About the 239-RTD
During the operation of this model when being used in the Motor Protection Relay series, which was manufactured by General Electric Three types of RTDs that can be used with the 239-RTD model are one-hundred-ohm nickel, one-hundred-and-twenty-ohm nickel, and ten-ohm copper. Proper programming is required so that when the RTD has been installed the input of the corresponding RTD is correct. When being used outside of the factory the RTD for this relay is one-hundred-ohm platinum.
The 239 is a relay that senses signals provided by the motor bearings and/or the RTDs that are placed in the stator slots. An internally connected ground safety is available on the 239-RTD model in terminal thirteen. If using the ten-ohm copper RTD with this relay please take care that the lead resistance is at the lowest range possible.
The working temperature range of this model is about negative forty to two hundred degrees Celsius, which equates to negative forty to four hundred degrees Fahrenheit. There is also an alarm/trip temperature range of around zero to two hundred degrees Celsius. The dead band for this relay is two degrees Celsius (four degrees Fahrenheit). The accuracy of the 239-RTD is either positive or negative two degrees Celsius.
The Pt or Ni RTD has a lead resistance of 25 Ω ohm max. The Cu RTD has a lead resistance of 3 Ω ohm max with three-wire lead resistance compensation.
More information about the operation, installation and other features of the 239-RTD can be found in the 239 Motor Protection Relay Instruction Manual. The order code that helps determine the model type and some of its functions can be found in the first chapter of the manual on page seven.
