US3836820A

US3836820A - Manual motor starter combined with fused circuit protectors

Info

Publication number: US3836820A
Application number: US00336995A
Authority: US
Inventors: J Cataldo; Marco B Di; F Kussy
Original assignee: ITE Imperial Corp
Current assignee: ITE Imperial Corp
Priority date: 1973-03-01
Filing date: 1973-03-01
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17

Abstract

A manual motor starter having interchangeable heaters for its overload sensing means is combined with fusible motor shortcircuit protectors (MSCPs) to achieve electrical coordination in which the MSCPs provide protection against severe fault conditions and the overload sensing means of the manual motor starter provides protection against running overloads. The MSCPs act on a common trip bar mounted to operate a crank engageable with the common trip bar of the starter for automatic opening of the starter contacts in the event an MSCP blows. Each MSCP is electrically wired in series with one pole of the starter in a circuit position between the contacts and the heater of the overload sensing means, so that the protector is not bypassed if heater burnout produces a phase-to-phase short.

Description

United States Patent 9 1191 Di Marco et al.

1 51 Sept. 17, 1974 MANUAL MOTOR STARTER COMBINED WITH FUSED CIRCUIT PROTECTORS [75'] Inventors: Bernard Di Marco, Bellefontaine,

Ohio; Frank W. Kussy, l-laverford, Pa.; John B. Cataldo, Moorestown,

[73] Assignee: I-T-E Imperial Corporation, Spring House, Pa.

[22] Filed: Mar. 1, 1973 {21] Appl. No.2 336,995

52 us. 01. 317/1311, 200/50 A 51 110.0. ..H02h 7/08 58 Field of'Search....,... 200/50 A; 317/1 1140 A,

A [56] References Cited UNITED'STATES PATENTS 2,191,523 2/1940 Ellis 200/50 A 2,907,840 10/1959 Cole 200/50 A 2,919,328 12/1959 Kozacka 317/40 A 2,920,164 l/l960 Edsall 317/40 A 2,920,241 l/l960 Jacobs, Jr. et al... 317/40 A 2,965,809 12/1960 Edsall 317/13 R 3,518,597 3,581,032 5 1971 Christensen ..200/50A 6/1970 Platz et al. 337/46 Primary Examiner l. D. Miller Assistant ExaminerPatrick R. Salce Attorney, Agent, or FirmOstrolenk, Faber, Gerb &

' Soffen [5 7 ABSTRACT A manual motor starter having interchangeable heaters for its overload sensing means is combined with fusible motor short-circuit protectors (MSCPs) to achieve electrical coordination in which the MSCPs provide protection against severe fault conditions and the overload sensing means of the manual motor starter provides protection against'r'unning overloads.

The MSCPs act on a common trip bar mounted to operate a crank engageable with the common trip bar of the starter for automatic opening of the starter contacts in the event an MSCP blows. Each MSCP is electrically wired in series with one pole of the starter in a circuit position between the contacts and the heater of the overload sensing means, so that the protectoris not bypassed if heater burnout produces a phase-to-phase short.

, 9 Claims, 13 Drawing Figures PAIENIEDSEP 1 ram sum 1 0F 6 FII'l'alln HL U T PATENTEU SEPII mu I SHEU 2 'UF 6 PAIENIEBsEP x 71924 saw 3 or 6 MANUAL MOTOR STARTER COMBINED WITH FUSED CIRCUIT PROTECTORS This invention relates to electrical protective apparatus in general and more particularly relates to a manual motor starter combined with fusible motor short-circuit achieve to chieve both electrical and mechanical coordination.

Copending U.S. patent application [D-439(MCO)] Ser. No. 248,859, filed May I, 1972, by J. B. Cataldo and F. W. Kussy, for a Motor Protecting Means, assigned to the assignee of the instant invention, describes the cooperation of fusible motor short-circuit protectors with an electromagnetic contactortype motor starter. In such an arrangement, operation of a single MSCP is effective to operate a switch in the energizing circuit for the operating coil of the electromagnetic contactor causing the latter to open and deenergize the motor. i

For many motor starter applications, it is desirable to utilize a manual motor starter rather than the relatively expensive electromagnetic type starter. In accordance with the instant invention, a manual motor starter is electrically and mechanically coordinated with motor short-circuit protecting means. In particular, a multipole manual motor starter and an individual MSCP for each pole of the starter are placed within an enclosure having an openable cover. Each MSCP is wired in series circuit between the contacts of a single starter pole and the interchangeable heater for this pole, with the contacts being at the line end of the starter and the heater being at the load end. With this wiring arrangement, in the event a heater burns out and a phase-tophase short results, this short-circuit current will pass through the MSCP causing blowing thereof and thereby prevent total destruction of the apparatus. A common trip bar is provided for actuation by pins ejected from the MSCPs upon blowing thereof. This common trip bar is operatively connected by a crank to operate the latch release means ofthe starter contact operating mechanism whenever a single MSCP blows. The movable contact carrier of the starter is positioned to cooperate with a pair of levers to provide cover and switch interlocks. The cover interlock normally prevents opening of the enclosure cover when the starter is closed. This interlock is deflected to an inoperative position by the contact carrier when the starter is opened. Defeater means operable from outside the enclosure are provided to permit opening ofthe enclosure cover when the switch is closed. The switch interlock prevents closing of the starter unless the cover is closed. With the cover open, the switch interlock blocks closing movement of the contact carrier, and closing of the enclosure cover deflects the switch interlock so that it is no longer in blocking relationship with respect to the contact carrier.

Accordingly, a primary object of the instant inventionis to provide a novel construction for electrical protective apparatus adapted for motor starting.

Another object is to provide a novel combination of a manual motor starter and motor short-circuit protectors.

Still another object is to provide a combination of this type in which the MSCPs are connected in series with each pole of the manual motor starter at a circuit position between the contacts and overload sensing means heater in each pole.

A further'object is to provide a combination of this type in which blowing of a single MSCP results in mechanical movement for the latch release of the manual starter.

A still further object is to provide a combination of this type mounted within an enclosure and provided with cover and switch interlock means.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIG. 1 is a plan view of electrical protective apparatus constructed in accordance with teachings of the instant invention and including a manual motor starter in combination with fusible motor short-circuit protectors.

FIG. 2 is an end view looking in the direction of arrows 2-2 of FIG. 1.

FIG. 3 is an enlarged plan view of the electrical elements of FIG. 1 with the contact cover of the manual starter removed.

FIG. 4 is an end view looking inthe direction of ar rows 4-4 of FIG. 3, with the enclosure door partially open.

FIG. 5 is a fragmentary portion of the end view of FIG. 4 with the enclosure door in its closed position.

FIG. 6 is an enlarged plan view showing the defeater member actuated so as to release the cover interlock.

FIG. 7 is an exploded perspective showing the relation between the interlock members mounted within the enclosure and those mounted to the cover.

FIG. 8 is a side elevation of the manual motor starter looking in the direction of arrows 8-8 of FIG. 3.

FIG. 9 is a plan view showing the interaction between the common trip bar operated by the motor shortcircuit protectors and the common trip bar of the manual motor starter.

FIG. 10 is a front elevation of the motor starter trip bar.

FIG. 11 is an end view looking in the direction of arrows 11-11 of FIG. 10.

FIG. 12 is a cross-section of the motor starter load terminal taken through line 12-12 of FIG. 3, looking in the direction of arrows 12-12.

FIG. 13 is a cross-section showing the motor starter connecting point which receives leads extending from the short-circuit protector means.

FIG. 14 is an end view looking in the direction of arrows 14-14 of FIG. 13, showing the motor starter terminal connecting the load end of an MSCP to the motor starter.

Now referring to the Figures. Combination motor starter 20 of FIG. 1 includes pan-like enclosure 21 having openable cover 22 connected along one side of enclosure 21 by hinge 23. Screw 24 is used to maintain cover 22 closed against accidental opening thereof. Disposed within enclosure21 and secured to back wall 26 thereof are manual motor starter 25 and insulating slab 27. The latter supports three line end terminals 28 and three load end terminals 29. Each terminal 28 mounts an individual fuse clip 32, and each of the terminals 29 mounts an individual fuse clip 33. Each pair of

clips

32, 33 removably mounts an individual one of the three MSCPs 30.

Manual motor starter 25 is, with slight modification, the same as the device described in US. Pat. No.

3,518,597, issued June 30, 1970, E. T. Platz et al., for a Manual Motor Starter. As will hereinafter be seen, each MSCP 30 is connected electrically to an individual pole of starter 25. Each protector 30 is a fusible device .of the type described in detail in US patent application [CS-253] Ser. No. 98,423, filed Dec. 15, 1970. The procedure for selecting MSCPs 30 and the heaters 31 (FIG. 8) of motor starter 25 to achieve proper electrical coordination is set forth in detail in the aforesaid application Ser. No. 248,859.

Briefly, manual motor starter 25 includes springpowered mechanism 35 for operating movable contact carrier 36 up and down with respect to FIG. 8, so as to simultaneously close and open, respectively, all poles of starter 25. The bridging contacts 37 in all three poles of starter 25 are mounted to upward extensions of contact carrier 36 and are located toward the line end of starter 25. Interchangeable heater 31 is located near the load end of starter 25 and forms part of an overload trip means including U-shaped bimetal 38 which, upon being heated, deflects to the left to pivot common trip bar 40 counterclockwise with respect to its longitudinal pivot axis 41. This moves latch tip 42 extending from trip bar 40 downward to release latch 43 of operating mechanism 35, so that the latter opens starter 25 by moving contact carrier 36 upward thereby separating bridging contact 37 from spaced stationary contacts 44, 45.

Common trip bar 51 at the load end of protectors 30 is pivotally mounted adjacent slat 27 by pivot assemblies 52. The construction of trip bar 51 and mounting thereof are described in detail in the aforesaid copending application Ser. No. 248,859. The three transverse extensions 53 of trip bar 51 are each positioned in alignment with the ejectable trip indicating pin 54 of a different MSCP 30. When pin 54 of any one of the MSCPs 30 is released and moves downward with respect to FIG. 3, this pivots trip bar 51 into engagement with car 56 of interconnecting crank or lever 55 that is pivotally mounted at 57 to integrally formed upward extension 58 of insulating slab 27. The other end 59 of crank 55 (FIG. 9) extends through starter housing opening 18 (FIG. 8) and is engageable with extension 61. of manual starter trip bar 40. Spring 62 engages crank 55 at a point between pivot 57 and end 59 so as to bias crank 55in a clockwise direction; Thus, ejection of a single protector pin 54 operates common trip bar 51 which in turn pivots crank 55 counterclockwise with respect to FIG. against the force exerted by the crank biasing means 62, with crank tip 59 engaging trip bar 40 to pivot the latter counterclockwise with respect to FIG. 8, thereby releasing latch 43 that normally maintains contact operating mechanism 35 in a reset condition.

For each pole of manual motor starter 25, the current path between its line terminal 61 and its load terminal 62 proceeds from line side stationary contact 45 through bridging contact 37 to load side stationary contact 44 mounted on conducting strap 63, through insulation-covered wire 64 to the line end of a fusible protector 30, through protector 30 and insulatorcovered conductor 65 at the load end thereof to one leg of L-shaped connector 66 whose other leg supports one end of U-shaped heater 31, and through heater 31 to load terminal 62.

For reasons of safety, starter 25 should not be operable to its closed position unless enclosure cover 22 is closed, and cover 22 should be prevented from opening unless starter 25 is opened. Thus, device 20 is provided with interlock assembly 70 positioned between starter 25 and insulating slab 27. Assembly 70 includes bracket 71 secured by screws 72 to common plate 91 mounted to rear wall 26 of enclosure 21. L-shaped interlock levers 73, 74 are pivotally secured to bracket 71 by pin 75 that extends between spaced

legs

76, 77 of bracket 71 and through

levers

73, 74 at the junctions between the respective legs thereof.

Levers

73, 74 are positioned between

arms

76, 77 and are spaced from each other by spacer 78. The free ends of the horizontal legs of

levers

73, 74 are engaged respectively by

coil springs

81, 82 which bias the vertical legs of

levers

73, 74 toward the left side of movable contact carrier 36 when viewed in FIGS. 4 and 5, thereby urging insulating

projections

83, 84 on the vertical legs of the

respective levers

73, 74 through aperture 19 in the side of the starter housing.

With the starter in its open position, contact carrier 36 is in its raised position of FIG. 4 wherein insulating projection 83 of lever 73 rests against the left side of contact carrier 36, and insulating extension 84 of lever 74 is in blocking position below movable contact carrier 36. Thus, lever projections 84 block downward movement of carrier 36 so that starter 25 cannot be closed.

The closing of enclosure cover 22 (FIG. 5) causes formation 79 of Z-shaped bracket mounted to the inner surface of cover 22 to engage the sloping upper edge 85 of lever 74, thereby moving the latter counterclockwise so that insulating extension 84 is moved to the left of contact carrier 36 and closing motion of the latter is no longer blocked.

Operation of contact carrier 36 downward to close starter 25 enables insulating projection 83 of lever 73 to move over the top of contact carrier 36, thereby permitting clockwise movement of lever 73 so that hooklike formation 86 at the upper end of lever 73 moves into blocking relationship above formation 87 of cover bracket 80, resulting in interference between

formations

86, 87 should an attempt be made to open cover 22 with starter 25 closed. The angular relationship between the lower edge of lever extension 83 and the upper surface of contact carrier 36 is such that upward movement of contact carrier 36 causes cover interlock lever 73 to pivot counterclockwise with respect to FIG. 5 until formation 86 thereof moves to the left of bracket formation 87, thereby permitting cover 22 to be opened.

Should it become necessary to open cover 22 when starter 25 is closed, this may be accomplished by rotating defeater screw 88 clockwise with respect to FIGS. 1 and 3 by using a screwdriver to operate the head of screw 88 positioned outside of cover 22. The lower end of screw 88 is journaled within an aperture in bracket formation 87, and torsion spring 92, interposed between disc 89 and the inside of cover 22, biases the head of defeater screw 88 against the outer surface of cover 22 and also biases defeater 88 counterclockwise with respect to FIGS. 1 and 3. Defeater screw 88 carries eccentrically mounted disk 89 positioned between bracket formation 87 and cover 22. Disk 89 is keyed to screw 88 so as to be rotated by rotation of screw 88. This causes disk 89 to engage formation 191 at the upper free end of lever 73, thereby deflecting lever 73 counterclockwise with respect to FIG. 5.

Electrical protective apparatus may be tripped remotely by utilizing a solenoid (not shown) to actuate trip bar 51 or

other members

40 and 55 of the mechanical trip system.

Even though the instant invention has been described in connection with motor short-circuit protectors having very rapid rupturing characteristicsat short-circuit currents, it should be apparent to those skilled in the art that the term fused protector as used in the following claims is broad enough to encompass any type of fuse that is coordinated with the heater of the overload trip means.

Although in the foregoing preferred embodiments have been discussed, many variations and modifications will now become apparent to those skilled in the art, and it is therefore understood that this invention is not limited by the disclosure but only by the appending claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. Electrical protective apparatus including an enclosure having an openable cover, a multi-pole switch unit within said enclosure, a fused'protector section within said enclosure, and first means within said enclosure responsive to actuation of said section for causing said switch unit to open, first interlock means to normally prevent opening of said cover when said switching unit is closed, and second interlock means to normally prevent closing of said switch unit when said cover is open; said switch unit having a load terminal for each pole thereof at a load end thereof and having a line terminal for each pole thereof at a line end thereof; a first and a second pole of said switch unit including separable contact means at said line end and overload sensing means, including heater means, at said load end; said fused protector section including first and second fuse protector portions; conductor means electrically connecting said first portion between and in series circuit with the heater means and contact means of said first pole; conductor means electrically connecting said second portion between and in series circuit with the heater means and contact means of said second pole; said switch unit including a mechanism for opening said contact means of all poles simultaneously, said mechanism having a latchable part which when latched permits the contact means to be closed and when released permits said mechanism to open said contact means; releasable latch means for normally holding said part latched; a first trip bar operable by said overlaod sensing means, upon detecting overload conditions, to release said latch means; said first means including a second trip bar operable by said fused protector portions under fault conditions more severe than said overload conditions to operate the first trip bar and thereby release said latch means.

2. Electrical protective apparatus as set forth in claim 1 in which the first means also includes a pivoted member for transmitting motion of the second trip bar to said first trip bar.

3. Electrical protective apparatus as set forth in claim 1 in which the portions of the protector section are elongated and extend generally parallel to each other and to the sides of the switch unit; said first and second trip bars being generally parallel to each other; said second trip bar being at one end of the protector section near the load end of the switch unit.

- a first and a second pole of said switch unit including separable contact means; each of the contact means including a movable contact member; said switch unit also including a carrier to which the movable contact members are mounted; said carrier being connected to said mechanism for operation thereby from a first position wherein said switch unit is closed to a second position wherein said switch unit is open; said first interlock means including a first interlock member and biasing means exerting a force on said first interlock member urging it toward said carrier to a locking position wherein the first interlock member holds the cover closed, said carrier in operating from its said second to said first position moving said first interlock member against the force of the biasing means to a releasing position wherein said cover is no longer held by said first interlock member.

5. Electrical protective apparatus as set forth in claim 4 in which the second interlock means includes a second interlock member and biasing means exerting a biasing force on said second interlock member urging it toward said carrier to a blocking position in which said second interlock member prevents operation of said carrier from its said second to its said first position, said cover upon closing thereof operating said second interlock member against the force of its said biasing means to a non-blocking position wherein said carrier is operable to its said first position.

6. Electrical protective apparatus as set forth in claim 5 in which there is a bracket secured to said cover on the inside thereof; said bracket having a first formation to engage said second interlock member to move same from said blocking to non-blocking position when said cover is moved to its closed position; said bracket also having a second formation engaged by said first interlock member when the latter is in said locking position to prevent opening of said cover,

7. Electrical protective apparatus as set forth in claim 6 also including defeater means operable from outside said cover to move the first interlock member to its releasing position when the cover is closed; said bracket also having a formation to guide movement of said defeater means.

8. Electrical protective apparatus as set forth in claim 5 in which said switch unit includes a mechanism for opening said contact means of all poles simultaneously, said mechanism having a latchable part which when latched permits the contact means to be closed and when released permits said mechanism to open said contact means; releasable latch means for normally holding said part latched; a first trip bar operable by said overload sensing means, upon detecting overload conditions, to release said latch means; a fused protector section within said enclosure, and first means within said enclosure responsive to actuation of said section for causing said switch unit to open; said switch unit also having a load terminal for each pole thereof at a load end thereof and having a line terminal for each pole thereof at a line end thereof, and overload sensing means, including heater means, at said load end; said fused protector section including first and second fuse protector portions; conductor means electrically connecting said first portion between and in series circuit with the heater means and contact means of said first pole; conductor means electrically connecting said second portion between and in series circuit with the heater meansifand contact means of said second pole; said first means including a second trip bar operable by said fused protector portions under fault conditions move severe than said overload conditions to operate the first trip bar and thereby release said latch means.

tion near the load end of the switch unit.

Claims

1. Electrical protective apparatus including an enclosure having an openable cover, a multi-pole switch unit within said enclosure, a fused protector section within said enclosure, and first means within said enclosure responsive to actuation of said section for causing said switch unit to open, first interlock means to normally prevent opening of said cover when said switching unit is closed, and second interlock means to normally prevent closing of said switch unit when said cover is open; said switch unit having a load terminal for each pole thereof at a load end thereof and having a line terminal for each pole thereof at a line end thereof; a first and a second pole of said switch unit including separable contact means at said line end and overload sensing means, including heater means, at said load end; said fused protector section including first and second fuse protector portions; conductor means electrically connecting said first portion between and in series circuit with the heater means and contact means of said first pole; conductor means electrically connecting said second portion between and in series circuit with the heater means and contact means of said second pole; said switch unit including a mechanism for opening said contact means of all poles simultaneously, said mechanism having a latchable part which when latched permits the contact means to be closed and when released permits said mechanism to open said contact means; releasable latch means for normally holding said part latched; a first trip bar operable by said overlaod sensing means, upon detecting overload conditions, to release said latch means; said first means including a second trip bar operable by said fused protector portions under fault conditions more severe than said overload conditions to operate the first trip bar and thereby release said latch means.

4. Electrical protective apparatus including an enclosure having an openable cover, a multi-pole switch unit within said enclosure, first interlock means to normally prevent opening of said cover when said switching unit is closed, and second interlock means to normally prevent closing of said switch unit when said cover is open; a first and a second pole of said switch unit including separable contact means; each of the contact means including a movable contact member; said switch unit also including a carrier to which the movable contact members are mounted; said carrier being connected to said mechanism for operation thereby from a first position wherein said switch unit is closed to a second position wherein said switch unit is open; said first interlock means including a first interlock member and biasing means exerting a force on said first interlock member urging it toward said carrier to a locking position wherein the first interlock member holds the cover closed, said carrier in operating from its said second to said first position moving said first interlock member against the force of the biasing means to a releasing position wherEin said cover is no longer held by said first interlock member.

6. Electrical protective apparatus as set forth in claim 5 in which there is a bracket secured to said cover on the inside thereof; said bracket having a first formation to engage said second interlock member to move same from said blocking to non-blocking position when said cover is moved to its closed position; said bracket also having a second formation engaged by said first interlock member when the latter is in said locking position to prevent opening of said cover.

8. Electrical protective apparatus as set forth in claim 5 in which said switch unit includes a mechanism for opening said contact means of all poles simultaneously, said mechanism having a latchable part which when latched permits the contact means to be closed and when released permits said mechanism to open said contact means; releasable latch means for normally holding said part latched; a first trip bar operable by said overload sensing means, upon detecting overload conditions, to release said latch means; a fused protector section within said enclosure, and first means within said enclosure responsive to actuation of said section for causing said switch unit to open; said switch unit also having a load terminal for each pole thereof at a load end thereof and having a line terminal for each pole thereof at a line end thereof, and overload sensing means, including heater means, at said load end; said fused protector section including first and second fuse protector portions; conductor means electrically connecting said first portion between and in series circuit with the heater means and contact means of said first pole; conductor means electrically connecting said second portion between and in series circuit with the heater means and contact means of said second pole; said first means including a second trip bar operable by said fused protector portions under fault conditions move severe than said overload conditions to operate the first trip bar and thereby release said latch means.

9. Electrical protective apparatus as set forth in claim 8 in which the portions of the protector section are elongated and extend generally parallel to each other and to the sides of the switch unit; said first and second trip bars being generally parallel to each other; said second trip bar being at one end of the protector section near the load end of the switch unit.