WorldWide Drilling Resource

69 WorldWide Drilling Resource ® SEPTEMBER 2013 External Faults by Bill Corey Pentair Water Training Institute External Faults require an input to the drive so they can send a message to turn the pump off. When you look at input choices, they are: Unused, External Setpoint, External Fault, or Run Enable. External means something outside the drive is making a decision as to whether or not the drive runs. If I were concerned about the pipe breaking and flooding my basement, I might feel in- clined to purchase a moisture sensor and place it on the floor of the base- ment near the drain. Then, should a pipe break and water start to move toward the drain, it will touch the moisture detec- tor, the points on the bottom would make a connection and send a signal to the input of the drive. Once the signal reach- es the drive, it will turn the drive off be- cause the signal is on a circuit that says “External Fault” when it is energized. The same would be true if I were pumping out of a cistern and I had a float connected to the input of the drive that was saying the water level is too low, turn the drive off. The drive would then turn the pump off and trip on “External Faul t” which requires a reset. So some- one will have to go to the dr ive and p u s h t h e Fa u l t Reset button. The moisture detector we use wi l l reset itself, but some- one s t i l l has t o reset the drive. The float in the cis- t e r n w i l l r e s e t itself, but some- one will still have to reset the drive. External Fault can be a redun- dant system also. For example, if I were worried the pump would not shut off if the pres- su r e wen t t oo high, I might want to put a pressure switch in the l ine that would close i f t h e p r e s s u r e got to say 80 psi. Remember, when something closes, it completes the circuit, and being set in External Fault, the drive would turn the pump off. External Fault can be anything out- side the drive which completes a circuit by closing points, causing the drive to fault. It can be very useful in saving the motor of the pump and keeping a sys- tem running when it might otherwise need replacing. Some drives have two inputs and one output, giving you a lot of flexibility. Next month, we’ll talk more about what you can do with an input. Bill Bill Corey may be contacted via e-mail at admin@ worldwidedrillingresource.com Contact us! 850-547-0102