CENTER (MCC) PANELS

Technical Field

The present invention relates to the hybrid operation method of drawer units in Motor Control Center (MCC) panels, which is a system or method for motor control in general and which simplifies the retractable subunits located in the motor control center that connects the motor control components to the power supply and the mechanical locking means required for them and increases personnel safety in specifically.

Background of the Invention

Low voltage systems such as motor control centers and power distribution panels have been equipped with withdrawable unit designs for many years. Withdrawable units and the equipment placed inside, provide the advantage of quick change during maintenance and in case of malfunction, which reduces power outage times.

It is customary to switch the retractable unit to the TEST position for testing or maintenance purposes, where the load circuit is interrupted, only the control circuits of the relevant devices remain energized. Control circuit energy can also be cut off if desired. This location is often called the DISCONNECTED location. The position in which both control circuits and load circuits are energized is called the "ON" position.

One method of operating such a drawer unit is to place it partially or fully retracted on its shelf on the board where the drawer is placed. The drawers here have a second contact structure called auxiliary contact in addition to a contact structure called the main contact. Two contact structures are located at the back of the drawer. The load circuit contacts are designed for the connection between the distribution busbars positioned vertically at the back of the panel and the motor, while the control circuit contacts are designed for the connection to the auxiliary circuits cables that are used to control the load circuit elements.

However, drawers with this type of method have the risk of accidentally being closed to the closed position or returning to the fully removed position from the partially removed position. Such an accident can happen as a result of something falling on the drawer or accidentally leaning on a person. This kind of accidental change of position can cause a change in the current situation, which is dangerous. On the other hand, arc striking or arc flashing, flame formation can occur when one of the drawers is partially or completely retracted, which is very dangerous.

In a second operating method, the process of combining or separating the main contacts with the distribution bar is carried out from outside the drawer door by using the rotatable handle located inside the drawer and connected to the mechanism. This main branch can be mechanically interlocked with another arm that moves the contacts of the control circuit, or the same can be done using a single multi-position lever. The important thing here is that the drawer is fully seated and its door is closed during the control operation performed by touching the handle.

However, the disadvantage of these systems is that the locking mechanisms are very complex, expensive and take up a lot of space. In addition, complex operation steps are difficult for operators to learn and follow.

In the literature in the US patent application numbered US5642256 on the subject, “An interlock mechanism in a motor control unit is provided for preventing the motor control unit from being engaged with current carrying bus bars within an enclosure when a handle disposed on the motor control unit is in an ON position, the handle controls a switching device disposed in the motor control unit, the interlock mechanism interacts with the switching device and automatically engages when the control unit is connected to the current carrying bus bars whereby preventing the motor control unit from being disengaged from the current carrying bus bars once the control unit becomes engaged with the current carrying bus bars and the handle is moved to the ON position.” statements are included. In the said patent application, a locking mechanism for the motor control unit fed by the busbars is disclosed.

Again in the literature, in the US patent application numbered US2010157512, “A system and method for connecting supply power to motor control components includes use of a motor control center subunit with moveable supply power contacts. After a motor control center subunit is secured into a motor control center compartment, the supply power contacts may be advanced to engage supply power buses. For disconnection, the supply power contacts may be retracted and isolated from the buses before physical removal of the subunit. ” statements are included.

In the said patent application, the production method of the motor control center subunit with movable line contacts is disclosed.

Also in the literature, related to the subject in PCT application numbered WO2015074956A1, “Switching device comprising a housing, a first electrical contact and a second electrical contact. The switching device further includes a Geneva drive comprising a first drive wheel arranged to drive the first electrical contact between a first connected position and a first disconnected position relative to the housing. The Geneva drive further includes a second drive wheel arranged to drive the second electrical contact between a second connected position with respect to the housing and a second disconnected position. The Geneva drive also includes a drive wheel with a drive pin arranged to alternately drive the first driven wheel and the second driven wheel. ” statements are included.

The said patent application discloses a switching device comprising a housing, a first electrical contact and a second electrical contact.

Due to the reasons mentioned above, there has been a need for a method that enables the hybrid operation of drawer units in Motor Control Center (MCC) panels.

Explanation of the Invention Based on this position of the technique, the object of the invention is to present a method that enables the hybrid operation of drawer units in Motor Control Center (MCC) panels.

Another object of the invention is to introduce a simpler and therefore reliable new method to bring the drawer units used to energize and deactivate the motors located in the motor control centers to the ON, TEST and REMOVED positions.

Another object of the invention is to provide a method that allows the control circuit contacts to change their position independently of the load contacts.

Another object of the invention is to provide a method that prevents the main contacts from being removed or inserted when they are in the ON position.

Another object of the invention is to provide a method that simplifies the retractable subunits located in the motor control center and the mechanical locking means required for them.

Another object of the invention is to provide a method that increases personnel safety in the motor control center.

Explanation of Figures

Figure - 1 is the view of the motor control center panel where the drawer unit is placed, according to the invention,

Figure - 2 are the views showing the positions of the drawer unit which is the subject of the invention.

Reference Numbers

A- Motor Control Center Panel

1. Drawer Unit

2. Moving Contacts

3. Auxiliary Contacts 4. Input Circuit

5. Output Circuit

6. Mechanism Lever

7. Locking Button

Detailed Description of the Invention

In this detailed description, the innovation subject to the invention is explained only with examples that do not have any limiting effect for a better understanding of the subject.

The present invention relates to the hybrid operation method for Motor Control Center (MCC) panels (A) to bring the drawer units (1) to the ON, OFF and DISCONNECTED positions, which simplifies the retractable subunits located in the motor control center that connects the motor control components to the power supply and the mechanical locking means required for them and increases personnel safety in specifically and which is including moving contacts (2) positioned as load contacts and auxiliary contacts (3) positioned as control circuit contacts characterized in that; includes the method steps of fixing the drawer unit (1) to the motor control center panel (A) in order to connect said moving contacts (2) to the vertical distribution busbar, is bringing the drawer unit (1) to the "ON" and "OFF" positions with the help of the mechanism lever (6) located on the front face, after the drawer unit (1) is completely placed in the motor control center panel (A) and the front surfaces are aligned, the auxiliary contacts (3) positioned at the rear of the said drawer unit (1) are in the closed position when the said drawer unit (1) is in ON and ON positions, in order to bring it to the DISCONNECTED position, holding the drawer unit (1) by the handles while the drawer unit (1) is in the ON position, and at the same time pulling it back by pressing the lock button (7) and separating the drawer unit (1) from the engine control center panel (A).

Figure - 1 shows the view of the motor control center panel (A) where the drawer unit (1) is placed, according to the invention. Figure - 2 shows the views showing the positions of the drawer unit (1) which is the subject of the invention.

The drawer unit (1), which is the subject of the invention, basically consists of moving contacts (2), auxiliary contacts (3), input circuit (4), output circuit (5), mechanism lever (6) and locking button (7).

In this method, after the drawer unit (1) is completely placed on the rack in the motor control center panel (A), that is, when the front surfaces of all drawer units (1) are aligned, the load circuit is ON and It can be taken to OFF positions. Auxiliary contacts (3) positioned as control circuit contacts in both positions remain closed.

Said auxiliary contacts (3) are fixed at the rear of the drawer unit (1), and they open when the drawer unit (1) is pulled completely and close when it is fitted and fixed. The auxiliary contacts (3) change their position independently of the movable contacts (2) positioned as load contacts.

When the said movable contacts (2) are in the OFF position with retracted, the auxiliary contacts (3) are in the closed position while the drawer unit (1) is in a seated and safe position. The OFF position is also the TEST mode.

The said drawer unit (1) has a locking mechanism that prevents the movable contacts (2) from being removed or inserted when they are in the ON position.

The said drawer unit (1) is brought to the DISCONNECTED position in order to de energize both movable contacts (2) and auxiliary contacts (3).

In order to bring it to the DISCONNECTED position, while the drawer unit (1) is in the OFF position, the drawer unit (1) is held by the handles and at the same time the lock button (7) is pressed and pulled back. In this way, all contacts (2,3) are separated from each other. For maintenance and repair purposes, the drawer unit (1) is now completely suitable to be separated from the motor control center panel (A).