SUMP PUMP CONTROL SYSTEM

• US 3,800,205 A
• Filed: 05/15/1973
• Issued: 03/26/1974
• Est. Priority Date: 05/15/1973
• Status: Expired due to Term

• Current Assignee: David R. Zalar
• Original Assignee: David R. Zalar
• Inventors: Zalar, David R.
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US05/360,525
• Time in Patent Office: 315 Days
• Field of Search: 318/482 417/36,45 103/25 307/118
• US Class Current: 318/482
• CPC Class Codes: G05D 9/12 characterised by the use of electric means
• CPC Class Codes: H02P 25/04 Single phase motors, e.g. capacitor motors

Abstract

A solid state control system for starting a sump pump motor when the water rises up to high level probes and for stopping the sump pump motor when the water level drops below low level probes. The system is supplied with power from an A.C. line. A.C. is applied to the probes to avoid polarization and half-wave rectified current is taken from the probes circuits to operate a transistor and an SCR in series connection, the SCR being supplied with rectified, smoothed and regulated D.C. to enable use thereof as a latch to keep the motor running while the water level falls from the high level probes below the low level probes. For isolation, a reed relay is used to fire a triac in the motor circuit when the SCR conducts.

Claims

1. A sump pump motor control system comprising:

an A.C. soUrce;

an A.C. switching device operable to control application of A.C. from said source to the motor to start the pump;

low level probes and high level probes in the sump for sensing low and high levels of water, respectively;

a low level circuit connecting A.C. from said source to said low level probes to provide current flow when the water rises to said low level probes while preventing unwanted polarization effects thereto;

A high level circuit connecting A.C. from said source to said high level probes to provide current flow when the water rises to said high level probes while preventing unwanted polarization effects thereat;

means connected to said A.C. source for providing a D.C. supply;

a triggering device for said A.C. switching device for triggering it into pump motor energizing state;

a controllable turn-on turn-off device;

a controlled unidirectional device controllable to latch into conducting condition until the power applied thereto is interrupted;

means connecting said controllable turn-on turn-off device and said controlled unidirectional device in series circuit to control application of power from said D.C. supply to said triggering device;

means for applying direct current from said low level circuit to said controllable turn-on turn-off device to bias it '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' whenever the water rises to the low level probes thereby to enable said series circuit for control by saud controlled unidirectional device when the water thereafter rises to the high level probes;

means for applying direct current from said high level circuit to said controlled unidirectional device to render it conducting when the water rises to the high level probes provided said controllable turn-on turn-off device has been biased on, thereby to energize said triggering device and start the pump;

said controlled unidirectional device remaining conducting when the water drops below the high level probes to maintain pumping; and

said controllable turn-on turn-off device being biased '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' when the water drops below the low level probes thereby to stop the pump.

2. The invention defined in claim 1, wherein:

said controllable turn-on turn-off device comprises a transistor; and

said means for applying direct current from said low level circuit to said controllable turn-on turn-off device comprises a unidirectional RC circuit having a resistor, a rectifying diode and a charging capacitor in series connection whereby the positive half-cycles of the A.C. source charge said capacitor, and means connecting the voltage of said capacitor to the base of said transistor.

3. The invention defined in claim 2, wherein said low level circuit comprises:

a unidirectionally conducting diode in reverse-parallel connection across said rectifying diode and said charging capacitor for passing the negative half-cycle of the A.C. source to the low level probes.

4. The invention defined in claim 1, wherein:

said controlled unidirectional device comprises an SCR; and

said means for applying direct current from said high level circuit to said controlled unidirectional device comprises a unidirectionally conducting circuit having a rectifying diode and means connecting it to the gate of said SCR to conduct the positive half-cycles of the A.C. source thereto.

5. The invention defined in claim 4, wherein said high level circuit comprises:

a unidirectionally conducting diode in reverse-parallel connection with said rectifying diode for passing the negative half-cycles of the A.C. source to the high level probes.

6. The invention defined in claim 1, wherein said triggering device comprises:

a reed relay having an energizing coil in said series circuit and having a contact for controlling said A.C. switching device thereby to isolate the control circuit from the power circuit.

7. The invention defined in claim 6, wherein said A.C. switching device comprises:

a triac hAving main conduction terminals in the motor circuit and having a gate controlled by said reed relay contact.