Hard start kit for multiple replacement applications

[0001] This application claims benefit of priority to U.S. Provisional Application Ser. No. 61/281,141 filed Nov. 13, 2009.

[0002] The invention herein relates to a hard start capacitor replacement unit that is adaptable in the field for replacing any one of a plurality of multiple hard start modules.

[0003] Single phase induction motors of the type commonly used with air conditioner and cooling equipment compressors generally require some type of auxiliary start capacitor for starting the motor. If the motor is a permanent split capacitor motor, i.e. one that has a run capacitor permanently connected across the run and start windings the motor, the start capacitor is connected in parallel with the run capacitor. The start capacitor, also sometimes referred to as a “hard start capacitor,” is connected for a short period of time to start the motor, and the start capacitor is disconnected from the motor near or at the time the motor achieves its run speed. This time is generally on the order of 50-100 milliseconds. Therefore, the start capacitor is wired in series with contacts for disconnecting it. The contacts can be a part of a potential or control relay, or an electronic relay.

[0004] If the start capacitor or the relay controlling it fails, the motor will not start. It is then necessary to replace the start capacitor and control relay, and this generally must be accomplished at the site of the motor. For air conditioners and other cooling equipment, this site could be a home, an office, a warehouse or factory, store, or any other building. This complicates the task of replacing the start capacitor and its connecting relay, in that a wide variety of brands and sizes of air conditioning and cooling units are in use, and these units use start capacitors having a variety of capacitances. Therefore, unless a repairman has a replacement hard start kit available with the correctly sized start capacitor, the repairman cannot complete repair without returning to a shop or parts distributor that has an inventory of hard start capacitor replacement parts.

[0005] Having to return to a shop or parts distributor in order to obtain the necessary materials to complete a repair is inefficient and time consuming and also delays the time that the customer's cooling system can be returned to operation.

[0006] Therefore, it would be advantageous if a repairman could carry one hard start replacement unit that is adaptable to many air conditioning units, cooling units, or other equipment utilizing single phase motors requiring a start capacitor, so that the repairman could adapt the hard start replacement unit to the requirements at hand and complete the repair in a timely manner.

[0007] It is a principal object of the invention herein to provide a hard start capacitor replacement unit adaptable to more than one motor.

[0008] It is an additional object of the invention herein to provide a hard start capacitor replacement unit with selectable capacitance.

[0009] It is also an object of the invention to provide a hand start capacitor replacement unit with circuit interruption protection.

[0010] It is a further object of the invention herein to provide a hard start capacitor replacement unit that can be configured at a repair site to provide a desired selected capacitance.

[0011] It is also an object of the invention herein to provide a hard start capacitor replacement unit with at least four selectable capacitances.

[0012] It is another object of the invention herein to provide a hard start capacitor replacement unit with selectable capacitance that mounts in substantially the same space as an original start capacitor unit.

[0013] In carrying out the invention herein a hard start capacitor replacement unit is provided having a cylindrical container with a cover. A plurality of capacitors are provided within the container, each of said capacitors having a capacitance value. The cover mounts a common terminal electrically connected to common plates of each of said plurality of capacitors. The cover also mounts a plurality of capacitance value terminals spaced apart from the common terminal and from each other, with each capacitance value terminal respectively connected to a capacitor of a corresponding capacitance value. A relay has a contact and means for opening and closing said contact in response to voltage across start and run windings of a single phase electric motor. Wire means are provided for connecting one side of the contact of the relay to one of the start and run terminals of the electric motor. Wire means are also provided for connecting the other side of the contact of the relay to a cover terminal and for connecting another cover terminal to the other of the start and run terminals of the electric motor, at least one of the wire connections being to the common terminal on the cover and the other wire connection being to a capacitance value terminal, such that at least one capacitor is connected between the relay and the motor. The capacitance value terminal is selected to connect a capacitor of the desired capacitance value. Jumper wires are connected between capacitance value terminals on the cover to connect additional capacitors, in order to select a total desired capacitance value.

[0014] In other aspects of the invention, the capacitors are wound as individual sections of one cylindrical capacitive element. The capacitors may be metallized polymer capacitors. The film may be polypropylene with a zinc coating.

[0015] In another aspect of the invention, there are four capacitors within the cylindrical capacitor container. The values of the capacitors may be about 48 microfarads, about 48 microfarads, about 88 microfarads and about 112 microfarads, each having a corresponding capacitance value cover terminal.

[0016] In additional aspects of the invention herein, the cover has four capacative value terminals and a common terminal. The common terminal is centered on the cover. The cover terminals are separated by insulating barriers. Jumper wires are provided to selectably connect capacitance value terminals.

[0017] In yet another aspect of the invention, the cover includes circuit interruption protection.

[0018] In a further aspect of the invention, the relay is an electronic relay. The relay may also be a control or potential relay. The relay is sized to be accommodated above the capacitor container within the projected cylindrical envelope thereof. A cylindrical cap is received on the capacitor container and extends therefrom to surround the relay and cover terminals. The cap is frictionally retained on the capacitor container and may be removed to make connections to selected capacitance value cover terminals.

[0019] The foregoing and other objects and features of the invention herein will, in part, appear in the following detailed description of the invention and claims, taken together with the drawings.

[0029] The same reference numerals refer to the same elements throughout the various Figures.

[0030] With reference to FIG. 1, a hard start capacitor replacement unit 10 is shown, including a cylindrical capacitor container 12 and a cylindrical cap 14 fitted onto the container 12 and extending therefrom. With reference to FIG. 2, the cap 14 may be removed from the container 12, to expose the cover 16 of the container, an electronic relay 18, and wire means 20 providing desired electrical connections for the hard start capacitor replacement unit 10 to a motor 60.

[0031] The container 12 is preferably 2½ inches in diameter with a length of 5¾ inches and has a plurality of capacitors therein. In the embodiment shown and with reference to FIG. 3, four capacitors 22, 24, 26 and 28 are provided within the container 12. Also in the embodiment shown, the capacitors 22, 24, 26 and 28 are wound in a cylindrical capacitive element 30 having a common element terminal 32 at the bottom thereof and four capacitor terminals 23, 25, 27 and 29 at the top thereof.

[0032] The capacitors of capacitive element 30 are preferably metallized film capacitors concentrically wound together as the cylindrical capacitance element 30. The film is preferably polypropylene metallized with zinc and may be about 3.8 microns in thickness. This is an advantageous film for several reasons. First, start capacitors generally require a higher capacitance value than run capacitors, i.e., run capacitors generally have typical capacitance values in the range of about 15 to about 65 microfarads, whereas start capacitors may have typical capacitance values up to about 300 microfarads. Such high start capacitance values have generally been achieved with electrolytic capacitors because 300-microfarad capacitors with typical film thicknesses would be bulky and require a large container that may not fit into the space provided in an air conditioning unit or the like. However, with recognition that a start capacitor is utilized for about one second or less as the motor starts, it does not have to be rated at high voltage over a long period of time. Therefore, a thin film may be used and the required capacitance is attained in a reasonably sized capacitive element. A further advantage is that the resultant metallized film capacitive element has stable capacitance values over a relatively wide ambient temperature range, and also has a long service life.

[0033] The container is preferably filled with a dielectric fluid 34 and the cover 16 is provided with circuit interruption protection in the event the capacitive element fails, such as shown in FIG. 3 and described in U.S. Pat. No. 7,203,053. These are also advantages in fabricating the capacitors 22, 24, 26 and 28 for the hard start capacitor replacement unit 10 from metallized film.

[0034] Although it is preferable to provide the capacitors in a cylindrical capacitive element 30 wound of metallized film, the capacitors 22, 24, 26, 28 may be individual wound capacitors having respective ends electrically connected to form a common terminal. The capacitive element 30 may be provided with more or less than four capacitors if desired. The capacitors may also be provided as two or more capacitive elements each having multiple capacitors.

[0035] It is also contemplated to make a hard start capacitor replacement unit with a single multiple value electrolytic capacitor or multiple electrolytic capacitors that may be connected to provide selectable total capacitance values. However, according to present electrolytic capacitor technology, the container for such a capacitor or capacitors would necessarily be larger than the container for a metallized film capacitive element and the capacitance value would not be as stable over ambient temperature ranges.

[0036] In the hard stand capacitor replacement unit 10 shown and described herein, capacitor 22 has terminal 23 and preferably has a capacitance of 48 microfarads. Capacitor 24 has terminal 25, and also has a capacitance value of 48 microfarads. Capacitor 26 has capacitor terminal 27, and has a value of 88 microfarads, and capacitor 28 has capacitor terminal 29 and has a value of 112 microfarads.

[0037] As perhaps as best seen in FIGS. 5-8, the cover 16 mounts a common cover terminal 40 in the center thereof, and mounts capacitance value terminals 42, 44, 46 and 48 spaced apart from the common cover terminal 40 and from each other. The common cover terminal 40 is connected to common element terminal 32 of the capacitive element 30 and thereby to each of the capacitors 22, 24, 26 and 28. The capacitance value cover terminal 42 is connected with the terminal 23 of capacitor 22 and the capacitance cover terminal 44 is connected with the capacitor terminal 25 of capacitor 24. The capacitance cover terminal 46 is connected with the capacitor terminal 27 of capacitor 26 and capacitance value cover terminal 48 is connected with the capacitor terminal 29 of the capacitor 28. Therefore, the capacitance values of the capacitors 22, 24, 26, 28 are respectively available for wire connections at the corresponding capacitance value cover terminals 42, 44, 46, 48 on the cover 16 of container 12.

[0038] A cover insulation barrier 50 is also mounted to the cover 16 to better isolate the cover terminals. The cover insulation barrier 50 has a cylindrical portion 52 surrounding the common cover terminal 40 and has radial extending fins 54-58 that separate the other capacitance value cover terminals. An extra fin is shown, which would insulate another one or two cover terminals if an additional one or two capacitors were provided.

[0039] With reference to FIG. 4, a schematic of the operation of the start capacitor replacement unit 10 is shown. The electronic relay 18 has external terminals that accept wire termination clips, so that wire connections can be made between the common cover terminal 40, and the capacitance value cover terminals 42, 44, 46 and 48, as well as with the start and run terminals 62 and 64 of a motor 60. External terminals T-1 and T-2 of electronic relay 18 are internally connected with contacts 70 and 72 that may be closed by a contact bar 74, all schematically shown. The electronic relay 18 also has external terminal T-5, and the electronic relay 18 has circuitry indicated at 76 that monitors the voltage and the dv/dt between terminals T-2 and T-5 and controls the opening and closing of the contacts 70 and 72 in response thereto. Terminals T-2 and T-5 are connected to the start and run terminals 62 and 64 of compressor motor 60 by wires 20, so that the electronic relay is monitoring the voltage across the start and run windings. Terminal T-5 may also be connected between the start and run windings of motor 60. When the contacts 70 and 72 are closed, the electronic relay 18 connects the selected ones of the capacitors 22, 24, 26 and 28 across the terminals 62 and 64 in parallel with the run capacitor 66 to assist in starting the motor. A bleeder resister 78 discharges the capacitor(s) when contacts 70, 72 are open. A suitable electronic relay is available from Zhejiang Hongli Electric Co., Part No. HLR3800-6AM1D.

[0040] With reference to FIG. 9, the hard start capacitor replacement unit 10 may also be used with a control or potential relay 90 as shown in the schematic. The relay contacts 92 and 94 are closed by contact bar 74 to connect selected ones of capacitors 22, 24, 26, 28 across run terminals 62, 64 of motor 60, and contacts 92, 94 are opened by coil 96 when the motor 60 starts. Bleeder resister 98 is provided to bleed off the capacitor charge when the contacts 92, 94 are open.

[0041] It will also be appreciated that although the capacitors of the hard start unit 10 are shown connected across motor terminals 62, 64, the purpose of this connection is to connect the capacitors in parallel with the motor run capacitor of the motor, and any connection that accomplishes this is suitable.

[0042] In FIG. 4, the capacitors 22, 24, 26 and 28 are connected as also shown in FIG. 8, in which a first wire 80 connects T-1 of the electronic relay with the cover capacitance value terminal 48, which selects 112 microfarads of capacitance value. Jumper wire 82 between capacitance value terminals 48 and 46 connects an additional 88 microfarads of capacitance value into the circuit. Wire 88 connects the common terminal 40 to terminal T-5 of the electronic relay 18. Jumper wire 84 connecting capacitance value cover terminal 46 and capacitance value cover terminal 44 connects a further 48 microfarads into the circuit. Thus, in the configuration shown in FIGS. 4 and 6, a total capacitance of 248 microfarads is provided to start the motor 60 when the contacts of the electronic relay 18 are closed.

[0043] It will be appreciated that a variety of capacitance values may be selected by connecting various ones of the capacitance cover terminals to each other. Some preferred connections are shown in FIGS. 5-8. FIG. 5 shows connection of capacitor 28 by wire 80 at cover terminal 48 providing 112 microfarads, which is suitable for use where capacitance values in the range 108-130 microfarads are desired for the motor start. FIG. 6 shows connection of capacitors 26 and 28 by jumper wire 82 at cover terminals 46 and 48 providing 200 microfarads of capacitance value, which is suitable for desired capacitance values in the range of 189-227 microfarads. FIG. 7 shows all of the capacitors 22, 24, 26, 28 connected into the circuit at cover terminals 42, 44, 46 and 48 by jumper wires 82, 84 and 86 to provide a total 296 microfarads, which is suitable for use in applications requiring capacitance values in the range of 270-324 microfarads. FIG. 8 shows connection of capacitors 28, 26 and 24 by jumper wires 82 and 84 providing 248 microfarads, for use with applications requiring capacitance values of 233-280 microfarads.

[0044] If desired, the total capacitance values connected into the circuit can be further refined with possible capacitance values of 48 microfarads, 88 microfarads, 96 microfarads, 136 microfarads, 160 microfarads, 184 microfarads and 208 microfarads, being available in addition to the 112 microfarads, 200 microfarads, 240 microfarads and 296 microfarads configurations shown above.

[0045] Once the desired capacitance value is selected by placing appropriate jumper wires on the cover terminals, the cap 14 may be fitted over the container 12, to surround the cover terminals and electronic relay 18. The hard start capacitor replacement unit 10 has a suitable size and shape to be accommodated in the space provided for the original start capacitor, so the hard start replacement unit 10 is readily accepted for mounting in existing equipment.

[0046] As a result of the foregoing, a repairman can carry the hard start capacitor replacement unit 10 to repair site with confidence that a failed start capacitor unit can be replaced without need to return to a shop or parts distributor in order to complete the repair.

[0047] Accordingly, a hard start capacitor replacement unit has been described which fulfills the objects of the invention herein. It will be appreciated that various changes may be made by those skilled in the art without departing from the spirit and scope of the invention, which is limited only by the following claims.