About the 139-NSF-V-TC
Denoted by the TC characters at the end of the 139-NSF-V-TC relay number the output on this model is a thermal capacity meter. This output type helps determine when the relay is close to tripping due to the various operating conditions when the full load of the relay is either being used in a conveyor or grinding system. This meter type will indicate the approximate memory that has been charged as it corresponds to the heat buildup of the motor. There is a specific feature that will indicate that the relay is about to trip, this indicator is the meter approaching one hundred percent capacity. If a trip does take place the thermal capacity meter will indicate how much charge is left within the memory, and the amount of charge left will indicate an estimate of the lockout time remaining on the relay.
Relay 139-NSF-V-TC can be used in a variety of applications which includes the protection of the mechanics and personal safety of the pumps of the undercurrent features which can detect a closed discharge valve or potential loss of suction.
There are several relay testing types available on this model which includes start timer, unbalance, ground fault, and commissioning relay tests. Of course, there are different ways to test each of these features on the 139-NSF-V-TC model. To test the ground fault a single phase must be connected through the window of the current transformer and then slowly increase the current of the test set until the relay trips; please note that the ground fault light will be on when tripped. The current should be equal to the setting value of +0, -25% which will cause the ground fault to trip. If the alarm is enabled the auxiliary relay will activate at a current half of the chosen value.