139-120V

About the 139-120V

Model number 139-120V is one of the many models in the 139 Series of Motor Protection Relays that can be either vertically or horizontally mounted. All of the circuitry associated with this model is housed in a plastic case, the plastic case is a see-through high-impact dustproof cover that allows the user to view the control settings and various indicators easily. Along with the controls on the front panel of this model, there are switches located inside the relay. The switches inside the relay guarantee that the program can be adjusted to whatever requirements the user needs. 

An extra set of contacts, labeled as auxiliary relay contacts, are available on the 139-120V relay which can operate independently of the main relay contacts on this model. The auxiliary relays will operate on the same ratings as the standard relay contacts. The aforementioned internal switches are the switches that will be used to program the conditions which will activate the auxiliary relays. The typical program conditions for this relay are RTD overtemperature, undercurrent, immediate overload warning, and a ground fault alarm. 

Fourteen indicators make up the front panel of this relay. Each indicator has a different name and function. For example, indicator number ten is a ground fault light and will indicate when the earth leakage a.k.a ground fault surpasses the internally preset value of fifty percent. When the ground fault is being used with the 139-120V relay a separate current transformer is required to encircle the motor conductors when providing the sensing signals for this relay.