US3078392A - Automatic restarting arrangement for electrically driven irrigation pumps - Google Patents

Description

Feb.

V; P. BOLLESEN AUTOMATIC RESTARTING ARRANGEMENT FOR ELECTRICALLY DRIVEN IRRIGATION PUMPS Filed Aug. 10, 1959 INVENTOR.

ATTORNEY.

Fetenterl Eels. 19, 196

This invention relates generally to controls for electric motors and other electrical loads, and refers more particulerly to an automatic restarting arrange lent for controlling the operation of electrically driven irrigation pumps.

It is, h s for some time been, a conven tics in agricultural iri' ,tion to utilize elect cred porn 5 equipped v/l' opcr delivering water from a well or other s urce to a system of irrigation ditches or pipes. The ave.v lity of power through REA. facilities has facilitated and encouraged such systems. However, t. ere is at least one prob 1cm in such operations which, so for as I am. aware, hes not been satisfactorily solved.

The problem arises primarily from the fact that not infrequently there is a momentary interruption in the power supply line to the pump. One of the principal 25 causes of this phenomena is li htning. The momentary power interruption has the onset of deenergizing the starter solenoid, thus breaking the line to load contacts forming a part thereof. in conventional systems the starter remains open thereafter, even though power is restored to the line, until the starter is manually reset.

As will be evident, unless an operator is directly at hand the topping of the motor may not be d t cted for some time. This has two quite iscoura 1g consequcnces. The first is that no water is pumped during the interval from shut-off to discovery. The second is that once pumping is interrupted for any enprecicblc period it cannot be cilectively commenced ag until the siphon tubes have been reset, which may tune as long as twohours.

It is one of the principal ooiects of y lo e provide a compact end fool-proof erran matically restarting electrically powered nature describ ruptiou. it is c. suture of controlled solely by elect independent power sources su In other words, succe onol pracly paw- 4d starters for eet 032 my invention restarting system of the c r described restarting is controlled to s" time interval has elapsed following pow and breaking of the st impo nt in pun n3 systems, as tendency to reverse direction. 7 will rotate in the oppor' should restarting he ii to rest, severe and end the pump 1g equipnier special feature of my n provided for prcsclccting to accommodate the resterter to varying conditions.

A still further object of my inve'irestartin" arrangement of character descri c which is automatically restored to its normal operating condiwhercin the is to provide a tion following resumption of current flow to the pump motor.

Other further objects of the invention together with the features of novelty apwrtensnt thereto will appear in he course of the following description.

In the sccornpsn i'sg drawing the single FlGURE represents a diagrammatic showing of a typical system embodying the invention.

Referring to the drawing, reference numerals 16, ill and 12 represent the power supply lines which are connected with a suitable source of alternating current (not shown). The supply lines are connected through switches 13, and 35, respectively, with the load lines l6, l7 and The load lines lend to a thre phase electric motor M which has driving connection with u. conventional pump P fitted with the intake and discharge lines 1? and respectively. it will be understood that the intake line 15 of the pump communicates with a suitable source of Water, such as a Well or the like (not shown) and that the discharge line feeds through the irrigation system (also not shown).

The switches 2.3, 14 and 15 form a part of the solenoid operated starter for the rue-tor M, being under the control ol a solenoid 2i. this connection it should be observed that the system is shown as in a condition prior to starting of the pump motor. The switches l3, l4 and 15 are biased in conventional fashion toward the open position illustrated, but will close upon encrgizetion of the solenoid 2t.

Currcnt is supplied to a. solenoid 21 through a circuit which includes supply line conductor 22, main power switch 23, conductor 24-, moment't y push switch 25, conouctors Z7 and solenoid El and conductor 29, the latter of which connects with line 11. To prepare the starter for normal operation switch 23 is manually closed. To start the motor, the momentary switch is then "cpressed, which causes current to flow through solenoid 211. Under the influence of the solenoid switches is, i l and 5 will close, thus closing the line circuit to the motor. The solenoid also acts upon a normally open locking switch 36 which has the effect of locking the solenoid. into energized circuit including conductor switch (now closed}, conductors 3i. and the locl ing switch 3%, conductor solenoid. El and conductor 'lhus the push switch rnoy now released without disrupting the supply of current to the motor.

The circuitry as thus far described is conventional in its general arrangecut and manner oi operation It will be eviocnt that should any powc terruption take place in the supply lines, even of a momentary na- 21 will be deco-em ed, thus permitting s me their normal open be closed without it is the purpose of my automatic starting arto eilcct clos w of the solenoid switches withretor the event the outcry nature.

provide a. ste wincling conling the sence o an cpower ijerrupti For the purposes or which has a ll.

my rnve down transformer l 5J1. nectcd in Series between lines and ll includes line solenoid switch 33, load line 17 or de t that at such cnductor Z22, switch .4513 conductor Ell, oriductor 27, winding 3-2, conductor solenoid switch It will be evis as the sole. is energized, or tne transformer.

former is cona so, c

The

the contact assumes the position shown in broken lines, thus closing a circuit from th rectifier through conduct-or 36, contact 35, conductor 3?, a capacitor 38 and conductor 39. So long as current flows through the motor M and thus through the winding of transformer T, contact 35 Will remain in the broken line position and the capacitor will be charged by current supplied from the rectifier.

It will be further observed that contact 35 is arranged to open and close a circuit which includes the capacitor 33, conductor 37, contact 35, conductor '42), relay coil 41 of the control relay and conductor 39 A variable resistance 42 is connected across the capacitor and in parallel therewith. The coil 41 of the control relay acts upon the normally open contact 43 which controls a bypass line 44 across the momentary manual push switch 25. For the purposes of this application I refer to the circuit including by-pass line 44 and contact 43 as the solenoid control circuit.

Assuming now that a momentary power interruption takes place, the following sequence of events occurs. Starter solenoid 21 is deenergized, thus causing starter switches 13, 14, and 38 to open. Transformer T is deenergized also and consequently flow of rectified current from the rectifier ceases. Thereupon the capacitor commences to discharge through relay coil 34.

The relationship and characteristics of the operating relay 34 and control relay 41 are important to an understanding of the invention. The characteristics of relay 34 must be such that its contact 35 will return to the solid line position at a time when the voltage impressed by the capacitor 38 is still high enough to cause the relay coil 41 to close its contact 43. In other words, the relay contact 35 must be set to open at a high enough voltage that the residual voltage in the capacitor, following opening of the contact 35, will still be enough to bring about closing of relay contact 43 by its coil 41.

The time interval between the start of decay in the capacitor and the opening of relay contact 35 is controlled by means of the variable resistance 42. As will be evident, the lower the resistance in resistance 42 the more rapidly the voltage supplied by the capacitor will be reduced. To increase the time interval between start of decay and the opening of the contact 35 it is necessary only to increase the resistance in the variable resistance. In practice a range of time delay of from fifteen seconds to three minutes has proved satisfactory. The setting of a proper time delay will depend largely on the characteristics of the pump, the load imposed thereon and the length of time required for the motor to achieve a quiescent condition.

After the preset time interval has passed, as explained above, contact 35 moves to the solid line position and the discharge of the capacitor is directed to the control relay coil 41 causing its contact 43 to close. if the power interruption has been only momentary (less than the time delay for which the unit has been set) the closing of contact 43 again energizes starter solenoid 21. This in turn causes closing of the solenoid switches 13, 14, 15 and with the result that power is again supplied from the supply lines to the motor. The winding of transformer T is at the same time energized, with the result that contact is returned to its capacitor charging position represented by the broken lines. Contact 43 will, of course, open again and the entire system is reset for operation as previously described.

The provision of the variable time delay makes it possible, when a number of pumps are on the same supply line, to stagger the restarting times for the individual pumps, thus to prevent the application of too great a load at one time on the line.

Once the motor is started the only way it can be 4 stopped, other than by power interruption, is by means i the manual main power sw' ch 23.

From the foregoing it will be seen that this invention is one Well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the arrangement.

It will be understood that certain features and subcombinations are of utility and may be employed without eference to other features and subcornbinations. This is contemplated by and is within the scope of the claims.

Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. In an electrical system which includes a source of alternating current connected through a magnetic starter to a load, the starter having a starter solenoid and switches responsive thereto, an arrangement for automatically reconnecting the starter solenoid with the source for a predetermined interval and at a positively determined time delay following an interruption of the alternating current resulting in opening of said switches, said arrangement comprising, in combination, a solenoid control circuit including said starter solenoid and said source, a control relay, said relay having a normally open contact in said control circuit between said source and the starter solenoid, said contact operable upon closing of same to electrically connect said starter solenoid with said alternating current source, a capacitor, power conversion means connected with said system through said starter and providing a second source of power at times when said switches are closed, an operating relay connected with said second source and energized by same and having a two-position operating contact, said operating relay so constructed that the operating contact assumes a fir position until the voltage impressed on said operating relay drops below a preselected value, at which time said operating contact automatically shifts to its second position, circuit means governed by said operating contact and constructed to connect said capacitor with said second source when said operating contact is in said first position and with said control relay when said operating contact is in said second position, said preselected voltage value being high enough that the voltage from the capaci tor is sufi'icient to energize said control relay to the extent necessary to cause closing of its associated contact, and known resistance means connected in parallel with the capacitor whereby to obtain a positively controlled rate of decay in said capacitor.

2. The arrangement as in claim 1 wherein said resistance means comprises a variable resistance operahle to provide for varying the rate of decay of the capacitor thus to change the time interval between failure of power at the second source and the shifting of the operating contact from its first to its second position.

References Cited in the file of this patent UNITED STATES PATENTS 2,059,836 Anderson Nov. 3, 1936 2,068,600 Frese Jan. 19, 1937 2,280,898 Dyer Apr. 28, 1942 2,342,821 Reagan Feb. 29, 1944 2,482,524 Vrooman Sept. 20, 1949 2,721,300 Myles Oct. 18, 1955 2,864,049 Sheets Dec. 9, 1958 OTHER REFERENCES The Electric Journal, vol. 34, No. 5, May 1937, Capacity-Stored Energy for Circuit-Breaker Tripping, pages 193, 194.

Claims (1)

1. IN AN ELECTRICAL SYSTEM WHICH INCLUDES A SOURCE OF ALTERNATING CURRENT CONNECTED THROUGH A MAGNETIC STARTER TO A LOAD, THE STARTER HAVING A STARTER SOLENOID AND SWITCHES RESPONSIVE THERETO, AN ARRANGEMENT FOR AUTOMATICALLY RECONNECTING THE STARTER SOLENOID WITH THE SOURCE FOR A PREDETERMINED INTERVAL AND AT A POSITIVELY DETERMINED TIME DELAY FOLLOWING AN INTERRUPTION OF THE ALTERNATING CURRENT RESULTING IN OPENING OF SAID SWITCHES, SAID ARRANGEMENT COMPRISING, IN COMBINATION, A SOLENOID CONTROL CIRCUIT INCLUDING SAID STARTER SOLENOID AND SAID SOURCE, A CONTROL RELAY, SAID RELAY HAVING A NORMALLY OPEN CONTACT IN SAID CONTROL CIRCUIT BETWEEN SAID SOURCE AND THE STARTER SOLENOID, SAID CONTACT OPERABLE UPON CLOSING OF SAME TO ELECTRICALLY CONNECT SAID STARTER SOLENOID WITH SAID ALTERNATING CURRENT SOURCE, A CAPACITOR, POWER CONVERSION MEANS CONNECTED WITH SAID SYSTEM THROUGH SAID STARTER AND PROVIDING A SECOND SOURCE OF POWER AT TIMES WHEN SID SWITCHES ARE CLOSED, AN OPERATING RELAY CONNECTED WITH SAID SECOND SOURCE AND ENERGIZED BY SAME AND HAVING A TWO-POSITION OPERATING CONTACT, SAID OPERATING RELAY SO CONSTRUCTED THAT THE OPERATING CONTACT ASSUMES A FIRST POSITION UNTIL THE VOLTAGE IMPRESSED ON SAID OPERATING RELAY DROPS BELOW A PRESELECTED VALUE, AT WHICH TIME SAID OPERATING CONTACT AUTOMATICALLY SHIFTS TO ITS SECOND POSITION, CIRCUIT MEANS GOVERNED BY SAID OPERATING CONTACT AND CONSTRUCTED TO CONNECT SAID CAPACITOR WITH SAID SECOND SOURCE WHEN SAID OPERATING CONTACT IS IN SAID FIRST POSITION AND WITH SAID CONTROL RELAY WHEN SAID OPERATING CONTACT IS IN SAID SECOND POSITION, SAID PRESELECTED VOLTAGE VALUE BEING HIGH ENOUGH THAT THE VOLTAGE FROM THE CAPACITOR IS SUFFICIENT TO ENERGIZE SAID CONTROL RELAY TO THE EXTENT NECESSARY TO CAUSE CLOSING OF ITS ASSOCIATED CONTACT, AND KNOWN RESISTANCE MEANS CONNECTED IN PARALLEL WITH THE CAPACITOR WHEREBY TO OBTAIN A POSITIVELY CONTROLLED RATE OF DECAY IN SAID CAPACITOR.

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