Hey BD and any other electricions

I asked a question last fall about the KVahr and power factor with my irrigation pump, and you suggested capacitors for power factor correction. I now have a one which will be put in soon.

Now the reason I may be interested in soft start / stop is completly another story.

Wednesday night I decided to fire up the irrigation system to get ready for the spring. This pump is oversized for what I am currently using it for and to compensate I was dumping a 4" pipe back into the reservoir. This worked fine, but last fall I ran a large enough area that I was able to close the 4" dump valve and close the isolation valve by half at the pump head and still maintain about 60 psi in the system.

Late last fall I was using the pump system to fill another reservoir. At this time I closed a 4 acre section of the irrigation off. After I filled the reservoir I recaped the supply line. I did not however reopen the 4 acres. I then forgot about everthing until the other night.

I shut off another two 1-1/2" lateral lines which broke while working with the excavator this winter. Now insead of running 25 lateral lines I think I am going to run 23, (but I am really only running 16.)

I push the green button in the pumphouse and walked outside to watch the presure gage on the filter outlet. It takes a while to build pressure as the supply line was drained. Slowly the pressure builds, 20, 30, 40, 50, 60 oh no that field isn't running, 70 ... I run in and hit the off. 80psi should be fine for the system but...

The anti flow back valve slamed shut. With so few sprinklers to disipate the water and presure the system kicked. I was lucky to be inside the pumphouse. The spike in presure sheared the 8" sched 80 pvc clear through at the Victolic grove connection to the filter. I never liked thouse Victolic connections.

For 5 seconds ( it seemed like a lot longer)the pumphouse and the surrounding 30 foot dia. was hosed down with the supply line under its own pressure. It was kind of scarry.

Anyway, I mannaged to get a new piece of sched. 80 to the machine shop and got a grove cut in. I'll put it back together Monday, hopefully nothing else broke like the 10" supply line.

Now you know why I'm thinking about soft start/stop. Sorry about the long story, Grant

I'll keep searching, never know what will come up. Grant

I'll keep searching, never know what will come up. Grant

Most of what I work on now are Schnieder 's. These VFD's are fairly intellegent and uses AC induction motors as "stepper motors". Desired rpm, actual rpm, current and torque required to maintain rpm along with position is all calculated on the fly. The machine will slow and stall rather than break a tool if something jams. Yet at all times know the positions to .1mm on the linear travel motions. Or .0004 thousands of an inch. A "M" set is done 1st without anything attached to the motor shaft. The VFD rocks the motor forwards and backwards a few times then knows exactly down to a fraction of a degree where that shaft is. An encoder is attached to the drive and sends pulses back through Profie Buss into a fiber optic convertor for the Scada system. The Scada fiber optics is daisy chained through 14 of the main drive amps (VFD). And out to the main PLC panel in the control trailer. There is a link over to the data gathering trailer too for when the UDM is slaved to the inspection tool. A 3rd locator system called a resolver takes direct measurements off the tool and machine mechanisms. This data is also fed back through the same way as the encoders. There are days installing a VFD on a pump, a simple plc and the two pressure and flow transmiters would be a relief.