MOTORS REMOTELY

DESCRIPTION

The invention concerns a modular central unit designed to remotely power and control the electric motors that operate machines and/or systems.

It is known that the drive motors of machines and systems, especially in large plants, are frequently powered and controlled by means of remote centralized systems that are usually designated by the acronym MCC, meaning“Motor Control Center”.

These centralized systems use a plurality of central units that are housed in appropriate electric cabinets installed in remote positions with respect to the motors of the machinery that they are intended to power and to control.

Embodiments are known in which each central unit comprises a frame, configured in the shape of a drawer, which can be slided into and out of a corresponding electric cabinet that is structured in such a way as to accommodate a plurality of drawers.

The electric cabinet is arranged in proximity to the electric power supply network, which comprises a plurality of metal bars to which the central units are connected when the drawer where each of them is accommodated is inserted in the electric cabinet.

More specifically, each central unit comprises:

- a disconnector provided with connection means for connection to the metal bars;

- a switch electrically connected to the disconnector, from which the power supply cables of the respective motor and of any auxiliary electric devices for the control of the motor itself branch off;

- a drive unit for the disconnector and the switch, accessible from the outside through manoeuvring means placed at the disposal of an operator.

More specifically, the drive unit can be accessed from the external front side of the drawer through manoeuvring means that allow an operator to operate the disconnector and the switch to supply power to or disconnect power from the respective users.

As already explained, the supporting structure with all the central units associated with it is installed in a remote position with respect to the motors and this allows the operating point for the control of all the motors making up the system to be concentrated in a single area.

Furthermore, in case of failure of the central unit, the operator replaces it by performing the following operations:

- opening the switch;

- uncoupling the disconnector from the metal bars;

- withdrawing the faulty central unit from the supporting structure;

- replacing the faulty central unit with a spare one;

- coupling the disconnector with the metal bars;

- closing the switch.

In this way, the operating conditions of the motor and therefore of the system or the machine to which the motor belongs are restored almost immediately and the faulty central unit can be checked in a lab and repaired at a later moment.

In the central units available on the market, independently of their construction structure, the drive unit is usually provided with convenient safety devices suited to guarantee that the switch and the disconnector are selectively manoeuvred so that:

- the switch closing manoeuvre can be performed only once the disconnector has been coupled with the metal bars of the electric power supply network;

- the manoeuvre to uncouple the disconnector from the metal bars of the power supply network can be performed only once the switch has been opened.

Central units are known, in which the drive unit and the disconnector constitute a single body, in one block, in which the mechanisms allowing the switch and the disconnector to be selectively manoeuvred are contained.

Said central units are sized for systems in which the values of the current to be interrupted are of the order of 300 A and therefore the disconnector that is used in said central units is oversized if the central unit to which it belongs is used to power loads absorbing current values much lower than 300 A.

A central unit of the type just described above is known from the patent document WO 201 1/000838 A1.

It should be considered that the problem of size is not secondary in systems, especially in the case of big plants comprising a large number of motors or a large number of loads to be powered, since in these cases the use of central units that are uselessly oversized involves a waste of space and an unjustified increase in costs.

In these cases, for example to power loads that absorb currents of the order of 63 A, special small sized central units have been developed, which are suited to be accommodated in smaller drawers.

These central units differ from those just described above in that the drive unit with which they are provided manoeuvres only the switch, since the disconnector comprises a plug that is integral with the drawer and is fitted into a corresponding fixed socket electrically connected to the metal bars when the drawer is inserted in the supporting structure

Obviously, safety means are provided which allow the drawer to be inserted in/extracted from the supporting structure and thus the plug and the related socket to be coupled/uncoupled only if the switch is respectively open or closed.

Central units of the latter type are smaller and less expensive than the central units described above and suited to interrupt currents of the order of 300 A, therefore they are much appreciated by users.

However, this involves the drawback of higher costs for the manufacturers, who need to construct and manage central units of two types, completely different from each other.

Furthermore, the central units just described above pose a limitation, which lies in that the disconnector coupling and uncoupling manoeuvres are performed through a mechanical displacement of the drawer, which is carried out manually by the user, and are thus less precise and less controlled manoeuvres compared to the coupling and uncoupling manoeuvres that are performed by acting on the drive unit through a manoeuvring key.

The present invention intends to overcome the drawbacks and the limitations listed above and for this purpose it is a first object of the invention to provide a central unit comprising a switch, a disconnector and a drive unit for the switch and the disconnector, in which the drive unit and the disconnector are configured so that they can be removably connected to each other.

It is another object of the invention to provide a drive unit that can be connected both to a disconnector provided with clamps for connection to metal bars connected to the current distribution network and to a disconnector provided with a plug/socket for connection to a respective socket/plug connected to the metal bars powered by the current distribution network. The objects mentioned above are achieved by a central unit for remotely powering and controlling electric motors according to the main claim, to which reference is made.

Advantageously, the invention makes it possible to standardize the production of central units by using a single drive unit that can be applied both to disconnectors equipped with clamps and to disconnectors equipped with plug and socket for connection to the metal bars connected to the electric power supply network.

Furthermore, advantageously, for safety purposes, the invention makes it possible to control the disconnector with no need to manually displace the drawer for connection/disconnection to/from the power supply network.

The objects and advantages listed above are achieved by the central unit according to the invention, which is described here below only by way of non limiting example, with reference to the attached drawings, wherein:

- Figure 1 shows an axonometric view of the central unit that is the subject of the invention;

- Figure 2 shows an exploded view of the central unit of Figure 1 ;

- Figure 3 shows an enlarged view of a detail of Figure 1 ;

- Figure 4 shows an exploded view of the detail of Figure 3;

- Figure 5 shows an enlarged detail of Figure 4;

- Figures 6 and 7 show enlarged details of Figure 3;

- Figure 8 shows a sectional view of the detail of Figure 7 according to section plane VIII;

- Figure 9 shows a top view of Figure 4;

- Figure 10 shows a view of Figure 9 after assembly;

- Figure 1 1 shows an axonometric view of Figure 10;

- Figure 12 shows an axonometric view of a variant embodiment of the central unit that is the subject of the invention;

- Figure 13 shows an exploded view of the central unit of Figure 12;

- Figure 14 shows an enlarged detail of Figure 12;

- Figure 15 shows an exploded view of Figure 14;

- Figure 16 shows an enlarged detail of Figure 15;

- Figure 17 shows a sectional view of Figure 13 according to section plane XVII - XVII.

The central unit that is the subject of the invention is represented in an assembled axonometric view and in an exploded axonometric view in Figures 1 and 2, respectively, where it is indicated as a whole by 100.

It is configured to be inserted in a frame 101 which can be removably associated with a supporting structure, not represented in the figures, which is substantially configured as a reticulated structure suited to accommodate a plurality of frames.

The central unit 100 comprises a disconnector 102 provided with connection elements 103 for connection to an electric power supply network, a switch 104 that can be electrically connected, through electric conductors not represented herein, to the connection elements 103 of the disconnector 102 and to an electric motor to be controlled, not represented, too, and a drive unit 105 for the disconnector 102 and the switch 104.

More specifically, with reference to Figures 3 and 4, the drive unit 105 comprises first drive means 106 for the switch 104 and second drive means 107 for the disconnector 102, especially visible in Figures from 9 to 1 1 and described in greater detail below, which can be accessed by an operator through a single manoeuvring handle 108 suited to be removably inserted in the drive unit 105 itself.

According to the invention, with special reference to Figures from 5 to 8, the disconnector 102 and the drive unit 105 are distinct from each other, are independent of each other and are removably connected to each other through a connection unit 110 comprising: a shaped housing 111 belonging to the drive unit 105, a shaped projection 112 belonging to the disconnector 102 and configured to be accommodated in the shaped housing 111 , and a shaped insert 113 configured to be inserted in the shaped housing 111 and to be placed in contact with the shaped projection 112 when this is accommodated in the shaped housing 111 , counteracting means 114 being provided which belong to the shaped housing 111 , to the shaped projection 112 and to the shaped insert 113 and which are configured to mutually cooperate and to constrain the shaped projection 112 in the shaped housing 111 when locking means 115 fix the shaped insert 113 in the shaped housing 111.

As to the drive unit 105, it can be observed that it comprises a shaped casing 116 in which the shaped housing 111 is obtained and which is connected to the first drive means 106 of the switch 104 and to the second drive means 107 of the disconnector 102 which, as already explained, are described in greater detail below.

As to the disconnector 102, instead, it can be observed that it comprises a shaped case 118 which is provided with the shaped projection 112 and which houses the elements 103 for connection to the electric network, said connection elements being known per se and comprising a plurality of connection clamps 136 configured to connect conductor bars which are electrically connected to the electric power supply network and are not represented herein.

The projection 112 protrudes from the shaped case 118 and is accommodated in the shaped housing 111 together with the shaped insert 113 that allows it to be constrained in the shaped housing 111 in a stable but removable manner when the locking means 115 fix the shaped insert 113 in the shaped housing

111.

In particular, the counteracting means 114 are shown in detail in Figures from 5 to 8, where it can be observed that they comprise a first stop pawl 119 which belongs to the end of the shaped projection 112 and is configured to be placed into contact with a corresponding end 113a of the shaped insert 113.

The counteracting means 114 comprise also a second stop pawl 120 that extends along the shaped insert 113 and is configured to be placed into contact with a corresponding first longitudinal housing 121 obtained along the shaped projection 112.

The counteracting means 114 furthermore comprise a third stop pawl 122 that delimits the shaped housing 111 longitudinally and is configured to cooperate with a corresponding second projecting edge 123 obtained along the shaped projection 112 and arranged opposite the first longitudinal housing 121.

Finally, the counteracting means 114 comprise also the bottom wall 124 of the shaped housing 111 which is placed into contact with two longitudinal ribs 125 that are parallel to each other and belong to the shaped projection 112.

As to the locking means 115 designed to lock the shaped insert 113 in the shaped housing 111 , they comprise two holed pins 126 projecting from the bottom wall 123 of the shaped housing 111 and two holed housings 127 belonging to the shaped insert 113 and configured to accommodate the holed pins 126 when the shaped insert 113 is introduced in the shaped housing 111. The shaped insert 113 is then fixed in the shaped housing 111 through screws 128 that are screwed into the holes of the respective holed pins 126 and holed housings 127.

Obviously, in other embodiments the holed pins 126 and the holed housings 127 can be present in a number different from two.

In order to allow the drive unit 105 to be manoeuvred in the shaped body 116, a first through opening 129 is provided, which is associated with a first revolving bushing 130 connected to the first drive means 106 of the switch 104 and configured to accommodate the manoeuvring handle 108 inserted therein. As to the first drive means 106 of the switch 104, they can be seen in greater detail in Figures from 9 to 1 1 and comprise a manoeuvring shaft 133 which connects the first revolving bushing 130 to the switch 104.

The shaped body 116 is also provided with a second through opening 131 which is associated with a second revolving bushing 132 that is connected to the second drive means 107 of the disconnector 102 and is also configured to accommodate the manoeuvring handle 108 inserted therein.

As to the second drive means 107 of the disconnector 102, they are visible in Figures from 9 to 1 1 , too, and comprise a pinion 134 associated with the second revolving bushing 132 and configured to mesh with a rack 135 which is connected to the elements 103 for connection to the electric power supply network and is slidingly associated with the shaped case 118 that encloses the disconnector 102.

Selective closing means not represented herein are also provided, which are designed to close the through openings 129 and 131 and are configured in such a way as to close the second through opening 131 and prevent the disconnector 102 from being manoeuvred when the first through opening 129 is open and to close the first through opening 129 and prevent the switch 104 from being manoeuvred when the second through opening 131 is open.

It should be noted that the selective closing means designed to close the through openings 129 and 131 and the respective drive means are not described herein, since they can be carried out in a plurality of different embodiments, some of which are known per se.

More specifically, the selective closing means of the present invention are the same that belong to the central unit described in the patent document PCT/EP 2010/059220 filed in the name of the same applicant that is filing the present patent.

Consequently, their embodiment is completely irrelevant for the purpose of functionality and for the achievement of the objects set for the central unit of the invention.

A variant embodiment of the central unit of the invention, indicated as a whole by 200, is represented in Figures from 12 to 17 and differs from the central unit 100 just described above only in that it comprises a disconnector, indicated as a whole by 202, whose size is smaller than that of the disconnector 102 just described above.

The central unit 200 is accommodated in a frame 201 and comprises a disconnector 202 provided with connection elements 203 for connection to an electric power supply network, a switch 204 electrically connected to the connection elements 203 and to an electric motor, not represented herein, and a drive unit 205 for the switch 204 and the disconnector 202.

The drive unit 205 comprises a shaped casing 216 which houses the first drive means 206 of the switch 204 and the second drive means 207 of the disconnector 202 which are described in detail below and can be accessed by an operator through a single removable manoeuvring handle 208.

Even in this variant solution, the disconnector 202 and the drive unit 205 are distinct from each other, independent and removably connected to each other through a connection unit 210 that comprises a shaped housing 211 belonging to the drive unit 205, a shaped projection 212 belonging to the disconnector 202 and configured to be accommodated in the shaped housing 211 and a shaped insert 213 configured to be inserted in the shaped housing 211 and to be placed in contact with the shaped projection 212 in order to constrain it when this is accommodated in the shaped housing 211.

For this purpose, with special reference to Figures from 14 to 17, there are counteracting means 214 belonging to the shaped housing 211 , to the shaped projection 212 and to the shaped insert 213, which are configured to mutually cooperate and to constrain the shaped projection 212 in the shaped housing 211 when the locking means 215 fix the shaped insert 213 in the shaped housing 211.

More specifically, the counteracting means 214 comprise a first stop pawl 243 that extends along the shaped insert 213 and is configured to be placed into contact with a corresponding first longitudinal housing 244 obtained along the shaped projection 212.

The counteracting means 214 comprise also a second stop pawl 244 that extends longitudinally along the shaped housing 211 and is configured to be placed into contact with a corresponding second longitudinal housing 245 obtained along the shaped projection 212 and located opposite the first longitudinal housing 244.

The counteracting means 214 furthermore comprise the bottom wall 224 of the shaped housing 211 that cooperates with the shaped projection 212.

Analogously to what happens with the variant embodiment previously described above, the locking means 215 designed to lock the shaped insert 213 in the shaped housing 211 comprise two holed pins 226 projecting from the bottom wall 224 of the shaped housing 211 and two holed housings 227 which belong to the shaped insert 213 and are configured to accommodate the holed pins 226 when the shaped insert 213 is inserted in the shaped housing 211.

The shaped insert 213 is then fixed in the shaped housing 211 through screws 228 that are screwed into the holes of the corresponding holed pins 226 and holed housings 227.

The drive unit 205, as already explained, comprises a shaped casing 216 in which the shaped housing 211 is obtained and which is connected to the first drive means 206 of the switch 204 and to the second drive means 207 of the disconnector 202 that are described here below.

As to the disconnector 202, it comprises a manoeuvring rod 240 which is slidingly associated with the frame 201 and is provided with a first end 241 that supports the connection elements 203 for connection to the electric network and with a second end 242 provided with the shaped projection 212.

More specifically, as can be observed in Figures 14 and 15, the shaped projection 212 is removably associated with the second end 242 of the manoeuvring rod 240 through a fixing block 253 belonging to the same shaped projection 212.

Furthermore, the counteracting means 214 belonging to the shaped housing 211 , to the shaped projection 212 and to the shaped insert 213 are configured to slidingly constrain the shaped projection 212 in the shaped housing 211 when the locking means 215 fix the shaped insert 213 in the shaped housing

211.

As to the locking means 215, they comprise two holed pins 226 projecting from the bottom wall 223 of the shaped housing 211 and two holed housings 227 belonging to the shaped insert 213 and configured to accommodate the holed pins 226 when the shaped insert 213 is introduced in the shaped housing 211. The shaped insert 213 is then fixed in the shaped housing 211 through screws 228 that are screwed into the holes of the corresponding holed pins 226 and holed housings 227.

In the shaped casing 216 there is a first through opening 229 provided with a first revolving bushing 230 that is configured to accommodate the manoeuvring handle 208 inserted therein and is connected to the first drive means 206 of the switch 204.

Also in this variant solution, the first drive means 206 of the switch 204 comprise a manoeuvring shaft 233 that connects the first revolving bushing 230 to the switch 204.

There is also a second through opening 231 provided with a second revolving bushing 232 which is configured to accommodate the manoeuvring handle 208 inserted therein and is connected to the second drive means 207 of the disconnector 202.

In the embodiment described herein, and differently from what happens in the embodiment previously described, the second drive means 207 of the disconnector 202 comprise a pinion 234 that is associated with the second revolving bushing 232 and meshes with a rack 235 that belongs to the shaped projection 212.

Finally, also in the present variant embodiment there are selective closing means designed to close the through openings 229, 231 and having the same functions as the selective closing means that have been described with reference to the embodiment of the central unit previously illustrated.

Therefore, when the manoeuvring handle 208 sets the second revolving bushing 232 and thus also the pinion 234 rotating, the latter causes the rack 235 to move and thus the shaped projection 212 to slide along the shaped housing 211.

In this way, the disconnector 202 is operated and consequently the manoeuvring rod 240 with which it is provided is moved, wherein said manoeuvring rod connects the connection elements 203 fixed to its first end 241 to the electric power supply network.

More specifically, the connection elements 203 comprise a multipole socket or a multipole plug 236 configured to be coupled with a corresponding multipole plug or multipole socket, not represented, connected to the electric power supply network.

Operatively, in the case of systems in which the current to be interrupted is of the order of 300 A, these use the central unit of the invention indicated as a whole by 100 and represented in Figures 1 and 2, which is housed in the frame

101.

Vice versa, in the case of systems in which the current to be interrupted is of the order of 30 A or less, it is preferable to use the construction variant of the central unit of the invention indicated as a whole by 200 and represented in Figures 12 and 13, which is housed in the frame 201 , which is smaller than the frame 101.

This is possible since, in line with the set objects, the drive unit and the disconnector are removably connected to each other through a connection unit that makes it possible to use the same drive unit and connect it to the two different disconnectors.

Advantageously, in this way the manufacturer benefits from a higher standardisation of the product and from savings in the management of the spare parts stored in the warehouse.

Furthermore, to advantage, the user, being able to choose from among central units of different sizes according to the conditions of use, can obtain significant reductions in volumes and costs, especially in the case of systems that use a large number of motors with different powers.

During execution, the central unit that is the subject of the invention can be subjected to modifications and variants that are not described herein and not represented in the drawings that accompany the present patent.

It is understood that if said modifications and variants fall within the scope of the following claims, they must certainly be considered protected by the present patent.