DESC:FIELD OF THE INVENTION

The present disclosure relates to submersible pumps. More particularly, the present disclosure relates to an improved submersible pump set comprising a motor unit including an in-built starter unit. The improved submersible pump set includes, for example, a single-phase submersible pump set for utilization of underground water in agriculture and commercial applications.

BACKGROUND OF THE INVENTION

A submersible pump is a versatile tool for the supply of underground water. A submersible pump set is different from an ordinary surface pump in that a submersible pump is fully submerged in water throughout its operation. These motors are generally constructed so that a rotor shaft at the top of the motor assembly provides motive power to a centrifugal pump mounted directly above the motor. In its operative environment, the composite pump and motor assembly lies beneath the surface of the liquid in a well.

Submersible pump sets are driven by induction motor technology either single phase or three phase. Single phase induction requires a starter panel which is mounted outside, and motor terminals are connected to the output terminals of the panel.

A motor starter panel or device generally comprises the following components:

1. Contactors – It is an electromechanical switching device. It is used to switch the motor ON-OFF whenever power supply connected to its auxiliary terminals.

2. Capacitor – Starter panels include electrolytic capacitors which are used as starting and running capacitors. A starting capacitor is used to improve the starting torque whereas a running capacitor is used to increase the motor power factor.

3. Overload Relay – An overload relay is used to protect the motor from any abnormal condition like overload. Overload relay consists of thermal bimetallic strip which cuts off the motor from supply whenever the motor gets heated.

In a conventional submersible pump setup, a control device including an external starter panel or device is usually manufactured separately and installed outside being connected to a submersible pump. The starter device is used to control the submersible pump which is required to be purchased and installed at the time of installation which requires time, labor and cost. The external starter panels or devices are also prone to failures for example, sparking in electromechanical switches fitted inside the panel (like contactors, Push buttons, etc.). The external starter panels usually also require regular maintenance, increasing the maintenance cost.

The present disclosure is intended to provide an improved submersible pump set with an in-built electronic starter unit eliminating the need for an external starter panel or device. The inclusion of an inbuilt starter unit provides the convenience of having the pump and starter integrated into a single unit simplifying installation and operation.

OBJECTS OF THE INVENTION

A primary object of the present disclosure is to eliminate the use of an external starter panel or device required for starting a submersible pump set.

Another object of the present disclosure is to an inbuilt starter unit reducing the cost which is necessary in case of using external starter panel or device and to provide a cost-effective and efficient improved submersible pump set.

Another object of the present disclosure is to provide an inbuilt starter unit having electronic circuit-based panel which removes the instances of failures which is usually faced by external starter panel or device due to for example, sparking in electromechanical switches fitted inside the panel (such as contactors, push buttons, etc.).

Another object of the present disclosure is to provide an improved submersible pump set which control the starting-up more stably and efficiently than a starter device or panel in the conventional art, and improve the life of the submersible pump set, the motor and the mechanical parts therein, as well as reduce instances of power loss and maintenance cost.

Another object of the present disclosure is to provide an inbuilt starter unit having electronic circuit-based panel which eliminates the need of additional space and cost required for a starter device or panel and its mounting structure and thus avoiding installation cost, labor cost and installation time.

Another object of the present disclosure is to avoid instances of motor failure because of selection of wrong components like capacitor, panel switchgear such as overload relay or wrong sized panel selection.

Yet another object of the present disclosure is to make motor rewindable so that it can be reused even after winding failure by simply rewinding.

A further object of the present disclosure is to provide an improved submersible pump set which simplifies the installation and operation thereof.

SUMMARY OF THE INVENTION

In order to achieve the above objects and advantages, the present disclosure relates to an improved submersible pump set comprising a motor unit including a starter unit integrally in-built and configured to be connected to an external power source and the motor respectively, for power supply from the external power source to the motor. Thus, the present disclosure relates to an improved submersible pump set comprising a motor unit including an in-built electronic starter unit required for starting the motor, for example a single-phase submersible motor. The starter unit includes the newly designed electronic circuit configured to be integrally fitted inside the submersible oil filled single phase motor.

The starter unit including the complete electronic circuit is circular in shape and configured to be in-built and/or fitted inside the submersible motor. The shape of starter unit is not limited to circular shape only and may vary as per the requirements and use, for example the starter unit may have a square shape or any other alternative geometrical shape.

As an example, a single-phase motor consists of starting and running winding. Three terminals of starting and running winding are connected to input terminals of the electronic circuitry of a starter unit. The electronic circuit of the starter unit works on the principle of timer. When the input signal / input supply is turned on, the control circuit timer gets started for 5 seconds and both windings are connected across input supply. Such a connectivity and process results in causing the motor to start rotating and the pump starts delivering the water. After 5 seconds the starting winding of the control unit is configured to get automatically disconnected from supply and thereafter the motor starts running completely on main winding i.e. running winding.

The control circuit of the starter unit consists of a special type of PCB mounted capacitors. Such capacitors are used to provide necessary starting torque to the motor during starting.

The complete electronic circuit of the starter unit is epoxy resin filled to compensate the heat generated inside the switching element. Additionally, the complete circuit of the starter unit is surrounded by oil which provides cooling to electronic circuit as well as limit the motor temperature rise.

The motor of the present invention is of the "oil-filled" type, i.e., a motor where the interior portion of the motor containing the stator and rotor are filled with a dielectric liquid material such as mineral oil. In such an oil-filled motor, the liquid well fluid in which the motor is submerged should be inhibited from entering the interior of the housing which houses the rotor and stator and, correspondingly, the oil in the casing should be inhibited from migrating outside the housing.

Accordingly, the present disclosure relates to a submersible motor unit comprising: a stator installed within a housing; a rotor arranged in a rotatable manner while being fixed to a rotor shaft at the center of the stator and the motor; an in-built starter unit arranged around the rotor shaft to energize the motor. The rotor shaft includes an upper end and a lower end supported by an upper bearing and a lower bearing respectively. The stator extends around and coaxial with the rotor being arranged within the housing having a tubular shape wherein a first end cap connected with a lower end of the tubular housing and a second end cap connected with an upper end of the tubular housing.

The starter unit including an electronic circuit being completely filled with epoxy in a circular cylindrical shape having a throughout hole in the center for receiving the rotor shaft. Three terminals of the winding i.e. starting and running winding terminals of the stator connected to the output terminal of the starter unit. The starter unit includes a PCB comprising: a MOSFET, a timer IC, one or more capacitor and resister, a snubber circuit, a MOV and a capacitor bank. The starter unit being integrally in-built connected to an external power source and the motor respectively, for power supply from the external power source to the motor.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

The foregoing and other objects, features, and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawing, wherein:

Fig. 1 illustrates a cross-sectional view of a motor of the submersible pump-set of the present disclosure;

Fig. 2 illustrates a printed circuit board (PCB) layout of a circular shaped timer based electronic circuit of a starter unit according to the present disclosure;

Fig. 3 illustrates the assembled PCB according to the present disclosure;

Fig. 4 illustrates a PCB mounted capacitor bank according to the present disclosure;

Fig. 5 illustrates the starter unit being epoxy resin molded according to the present disclosure;

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the presently disclosed disclosure will now be described in detail with reference to the drawings wherein like reference numerals designate identical or corresponding elements. In the drawings and in the description, the term "proximal", "bottom", "down" or "lower" refers to a location on the device that is closest to a user holding the device and/or any part thereof. Conversely, the term "distal", "top", "up" or "upper" refers to a location on the device that is farthest from the user holding the device and/or any part thereof.

As used herein, the terms first, second, third, etc. are understood to describe different structures/elements so as to distinguish one from another. However, the terms are not structurally limiting unless the context indicates otherwise.

Moreover, the Figures may show simplified or partial views, and the dimensions of elements in the Figures may be exaggerated or otherwise not in proportion for clarity. In addition, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a terminal includes reference to one or more terminals. In addition, where reference is made to a list of elements (e.g., elements a, b, c), such reference is intended to include any one of the listed elements by itself, any combination of less than all of the listed elements, and/or a combination of all of the listed elements.

Referring to Fig. 1, which illustrates a cross-sectional view of a motor 10 comprising a stator 12 installed within a housing 14, a rotor 16 arranged in a rotatable manner while being fixed to a rotor shaft 18 at the center of the stator 12 and the motor 10. The rotor shaft 18 includes an upper end and a lower end. The ends of rotor shaft 18 are supported by an upper bearing 20a and a lower bearing 20b. The stator 12 extends around and is coaxial with the rotor 16 being arranged within the housing 14. The housing 14 is tubular in shape. The housing 14 could be made of many different materials, for example the housing 14 could be made of non-magnetic stainless steel.

A first end cap 22a is connected with a lower end of the tubular housing 14. Similarly, a second end cap 22b is connected with an upper end of the tubular housing 14. The first end cap 22a and the second end cap 22b are circular in shape and disposed in a coaxial relationship with each other. The first end cap 22a and the second end cap 22b includes opening in center to receive the ends of the rotor shaft 18. Fluid tight connections are made between the first end cap 22a and second end cap 22b and tubular housing 14. The first end cap 22a defines a chamber 24 wherein a diaphragm 36 is connected with said first end cap 22a and arranged within said chamber 24. The diaphragm 36 is cup shaped. The upper end of rotor shaft 18 i.e. a drive shaft 32 passes through said second end cap 22b and is exposed which may be connected to an impeller unit (not shown). The impeller unit may be detachably connected to the pump 10 body through the drive shaft 32. The rotor 16 and the drive shaft 32 are rotatable relative to the stator 12 to drive a pump unit (not shown) in the pump and motor assembly when the electric motor 10 is energized.

In order to energize the motor 10, a starter unit 26 is arranged around the rotor shaft 18 in between the stator 12 and the second end cap 22b within the tubular housing 14. The starter unit 26 includes an input 30a and an output terminal 30b as shown in Fig. 5. A power supply (not shown) is connected to the input terminal 30a of the starter unit 26 to start, commutate and control the speed and torque of the motor 10 during operation of the submersible pump-set. The starter unit 26 including an electronic circuit is completely filled with epoxy in a circular cylindrical shape as shown in Fig. 5. The starter unit 26 having the cylindrical shape is provided with a throughout hole 28 in the center for receiving the rotor shaft 18.

The stator 12, not being limited to, is wound with enameled winding wire. In one example, entire stator 12 is filled with oil to avoid heat generation. The oil provides support for the tubular housing 14 so that it does not deflect or collapse under the influence of fluid pressure once the motor 10 is submerged within water. In addition, it is important to maintain the winding of the stator 12 and the rotor 16 against the entry of the liquid. For this reason, an oil filling is provided for the sealed space in which the winding is located. The oil picks up heat from the rotor windings and from the housing walls adjacent the stator windings and transfers the heat to the liquid flowing through the pump 10 via the pump body. The circulating oil also act as a lubricant for the components of the pump 10. The rotor 16 may be made of aluminum die casting which is used to improve the starting torque of the motor 10. The three terminals of the winding (i.e. starting and running winding terminals) of the stator 12 are connected to the output terminal 30b of the starter unit 26.

During operation of the motor 10 in the pump and motor assembly (not shown), a pump unit in the pump and motor assembly is configured to pump water upward from a water source for example a well through a conduit or pipe (not shown).

Referring to Fig. 2, a printed circuit board (PCB) 38 layout of a circular shaped timer based electronic circuit of the starter unit 26 including a control circuit is illustrated. The various components of the starter unit 26 are connected on said PCB 38 as shown Fig. 3. PCB 38 having the cylindrical shape is provided with a throughout hole 28 in the center in order to allow the rotor shaft 18 to pass therethrough. The starter unit 26 including the PCB 38 comprising the following components:

(i) MOSFET: MOSFET is a solid-state device which is used to cut off the starting winding of the motor 10 after specified time duration. MOSFET operates at high efficiency and at lower voltages. It has high speed of response.
(ii) Timer IC: The Operation of the electronics circuit of the starter unit 26 is based on timer. Timer IC is used to generate the gate pulses when the power is turned on. The timer IC provides a signal to MOSFET which turns on the MOSFET. As a result, starting winding of the motor 10 gets connected across the supply through capacitor bank.
(iii) Capacitor and Resister: Capacitor and register combination is used to define the duration of the gate pulse. The duration of gate pulse is calculated by using the formula below.
? = RC = 1 / 2 x p x fc
(iv) Snubber Circuit: It is used to protect the switching element that is MOSFET from getting damaged because of motor back EMF or reverse voltage generated across motor terminal.
(v) MOV: It is also known as metal oxide. Various types of metal oxide may be used to protect the control circuit from high voltage input surge and spikes.
(vi) Capacitor Bank: The control circuit of the starter unit 26 also consists of special PCB mounted capacitor bank(s) in order to provide necessary starting torque to the pump set. Such capacitor banks are shown in Fig. 4 which are connected being mounted on one side of the PCB. The capacitor 34 stores electrical energy which is utilized during starting of the motor 10. The capacitor 34 may produce a phase shift to give additional torque.

PCB 38 may include one or more of the above-mentioned components. The electronic circuit of the starter unit 26 works on the principle of timer. When the input signal / input supply is turned on, the control circuit timer gets started for five seconds and both windings of the stator 12 are connected across input supply. As a result of this the motor 10 starts rotating, and the pump starts delivering the water. After five seconds, the starting winding gets automatically disconnected from supply and the motor thereafter starts running completely on main winding i.e. running winding.

In view of the foregoing description, it is apparent that the present disclosure provides a new and improved submersible motor unit 10 for use in driving a pump with the pump and motor unit 10 submerged in liquid for example, water.

From the foregoing description, it will be appreciated that the improved submersible pump-set for underwater use for supply of water of the present disclosure represents a significant improvement over the prior art. While preferred embodiment(s) of the improved submersible pump-set and the process for manufacturing the same has been disclosed, it should be further appreciated that modifications may be made without departing from the scope of the present invention. In addition, while various features and components have been disclosed in an exemplary fashion, various other features and components may be employed. It is intended by the foregoing to cover these and any other departures from these disclosed embodiments which fall within the true spirit of this invention.

Thus, it is intended that the scope of the present invention herein disclosed should not be limited by disclosed embodiments described above but should be determined only by a fair reading of the appended claims.

List of reference numerals:

10 motor
12 stator
14 housing
16 rotor
18 rotor shaft
20a upper bearing
20b lower bearing
22a first end cap
22b second end cap
24 chamber
26 starter unit
28 hole
30a input terminal
30b output terminal
32 drive shaft
34 capacitor
36 diaphragm
38 PCB
,CLAIMS:WE CLAIM:

1. A submersible motor (10) unit comprising:
a stator (12) installed within a housing (14);
a rotor (16) arranged in a rotatable manner while being fixed to a rotor shaft (18) at the center of the stator (12) and the motor (10);
an in-built starter unit (26) arranged around the rotor shaft (18) to energize the motor (10).

2. The submersible motor (10) unit as claimed in claim 1, wherein the rotor shaft (18) includes an upper end and a lower end supported by an upper bearing (20a) and a lower bearing (20b) respectively.

3. The submersible motor (10) unit as claimed in claim 1, wherein the stator (12) extends around and coaxial with the rotor (16) being arranged within the housing (14) having a tubular shape.

4. The submersible motor (10) unit as claimed in any of the preceding claims, wherein a first end cap (22a) connected with a lower end of the tubular housing (14) and a second end cap (22b) connected with an upper end of the tubular housing (14).

5. The submersible motor (10) unit as claimed in claim 4, wherein the first end cap (22a) and the second end cap (22b) includes opening in center to receive the ends of the rotor shaft (18).

6. The submersible motor (10) unit as claimed in claim 4, wherein the first end cap (22a) defines a chamber (24) wherein a diaphragm (36) connected with said first end cap (22a) and arranged within said chamber (24).

7. The submersible motor (10) unit as claimed in claim 1, wherein the starter unit (26) includes an input (30a) and an output terminal (30b).

8. The submersible motor (10) unit as claimed in claim 1, wherein the starter unit (26) including an electronic circuit being completely filled with epoxy in a circular cylindrical shape having a throughout hole (28) in the center for receiving the rotor shaft (18).

9. The submersible motor (10) unit as claimed in any of the preceding claims, wherein three terminals of the winding i.e. starting and running winding terminals of the stator (12) connected to the output terminal (30b) of the starter unit (26).

10. The submersible motor (10) unit as claimed in any of the preceding claims, wherein the starter unit (26) includes a PCB (38) comprising: a MOSFET, a timer IC, one or more capacitor and resister, a snubber circuit, a MOV and a capacitor bank.

11. The submersible motor (10) unit as claimed in claim 1, wherein the starter unit (26) being integrally in-built connected to an external power source and the motor (10) respectively, for power supply from the external power source to the motor (10).