JPS636129Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an elevator control device, and more particularly to an elevator control device suitable for detecting an abnormality in a main contact of a main circuit.

In the past, if the main contacts of the main circuit were welded, depending on how the main circuit was connected, a short circuit could occur in the power supply, which could have an adverse effect on the power cables, transformers, circuit breakers, etc. on the building side.

An object of the present invention is to provide an elevator control device that prevents power supply short circuits due to welding of main circuit main contacts.

The feature of this invention is that the number of poles can be changed using a single winding.
In an elevator control device using a stepped speed three-phase induction motor, welding or poor contact of the main circuit main contacts is detected by the logic of the open/closed state of the contacts, and in response, the three-phase AC power supply is cut off. The main feature is that it prevents short circuits in the power supply.

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

FIG. 1 shows the main circuit of the present invention. Three-phase power supply R, S, T, normally open contact 1 of the magnetic contactor for rising operation
1 ₁ , 11 ₂ , Normally open contact 1 of magnetic contactor for downward operation
2 ₁ , 12 ₂ , Normally open contact 1 of magnetic contactor for high-speed operation
3 ₁ to 13 ₃ , Normally open contact 1 of electromagnetic contactor for low speed operation
4 ₁ to 14 ₃ , Normally open contact 1 of electromagnetic contactor for DC braking
5 ₁ , 15 ₂ , normally open contact 1 of the magnetic contactor for switching the number of poles
6 ₁ to 16 ₃ , thyristors SCR ₁ , SCR ₂ , diodes D ₁ , D ₂ as shown in the figure, high-speed side terminals U ₂ , V ₂ , W ₂ of a single winding two-speed three-phase induction motor IM, It is connected to the low-speed side terminals U ₁ , V ₁ , and W ₁ .

Next, the operation will be explained. As an example, explanation will be given using upward operation.

During acceleration, the contactors 11 ₁ and 11 ₂ for rising operation and the contactors 13 ₁ to 13 ₃ for high-speed operation are closed, and the thyristors SCR ₁ and SCR ₂ are connected in antiparallel. In other words, a thyristor with a three-phase induction motor IM connected in antiparallel
Primary one-phase voltage control is performed by SCR ₁ and SCR ₂ . The contacts 16 ₁ to 16 ₃ of the pole number switching contactor are closed at this time, and the three-phase induction motor is operated at high speed with the windings in a star shape.

During deceleration, the high-speed contactor contacts 13 ₁ to 13 ₃ open, the DC braking contactors 15 ₁ and 15 ₂ close, and the thyristors SCR ₁ , SCR ₂ , diodes D ₁ ,
Form a mixed bridge circuit consisting of D ₂ . At this time, the pole number switching contacts 16 ₁ to 16 ₃ are opened, and the windings of the three-phase induction motor IM are triangularly connected.
In this state, the three-phase induction motor IM is subjected to DC braking control using the DC obtained from the mixed bridge circuit.

A time chart of the above sequence is shown in FIG.

On the other hand, during low speed operation, high speed contactor contact 13 ₁
- 13 ₃ are open circuits, low speed contactors 14 ₁ - 14 ₃ are closed circuits, pole number switching contactors 16 ₁ - 16 ₃ are open circuits, and the three-phase induction motor IM is triangularly connected to operate at low speed.

Now, suppose that the contactor contacts 16 ₁ to 1 for switching the number of poles
If the contacts of 6 ₃ are welded, during deceleration, the three-phase induction motor IM becomes a star-shaped high-speed winding instead of the triangular connection as described above, and performs DC braking control. For this reason,
The DC braking torque becomes abnormal, and normal deceleration is not possible, resulting in a large landing error. If the landing error exceeds a certain level, the elevator will operate at low speed and land at the nearest floor. However, as shown by the broken line in Figure 1,
A short circuit occurs in the power supply along a path from the low-speed contactor 14 ₁ to the welded pole number switching contacts 16 ₁ and 16 ₃ to the low-speed contactor contact 14 ₃ .

To prevent this, a contact abnormality detection device is required. Figure 3 shows the contact abnormality detection circuit.

13 ₁ and 13 ₂ are normally closed and normally open auxiliary contacts of the high speed contactor 13, respectively. 16 ₁ and 16 ₂ are normally open auxiliary contacts of the pole number switching contactor 16, respectively. 16T
is a contact abnormality detector and an on-delay timer. FFBC is a tripping coil for the breaker that cuts off the elevator power supply.

As already explained and as is clear from the time chart in FIG. 2, the high-speed operation contactor 13 and the pole number switching contactor 16 open and close at the same timing. Therefore, if the contactor 16 for switching the number of poles is welded, the contactor 13 for high speed will open during deceleration.
The normally closed auxiliary contact 13 ₁ is closed. Since the contacts of the pole number switching contactor 16 are welded, the normally open auxiliary contact 16 ₁ is closed, and the contact abnormality detector 16T is energized along the path shown in the figure. After a certain period of time, this contact abnormality detector 16T is turned on and its normally open contact 16T ₂ is closed. When the normally open contact _16T2 closes, a contact abnormality is detected and the disconnection occurs.
Energize the FFB tripping coil FFBC to quickly turn off the power.

The elevator stops, but since the power has already been cut off, the contactor 14 for low-speed operation cannot be turned on next, and as described above, at this time, a power short circuit does not occur due to the turning on of the contactor 14. .

In addition, if the contact of the contactor for switching the number of poles has a contact failure, similarly, the contact abnormality detector 16T
A contact failure can be detected by energizing the FFB and tripping the breaker FFB.

According to this embodiment, it is possible to detect welding and poor contact of the contacts of the contactor for changing the number of poles, and to quickly cut off the power source to prevent short circuits of the power source.

Another embodiment will be explained with reference to FIG. The feature of this embodiment is the circuit shown in FIG. In Figure 4, the
Instead of the FFB tripping coil FFBC, the normally closed contact _16T3 of the contact abnormality detector is connected to the closing circuit of the contactors 11 and 12 for rising and falling operation, and the normally open contact 16T2 is connected to the closing circuit of the contactors 11 _{and 12} . Connect to contact abnormality indicator L. In addition, 21 ₁ is a normally open contact of the ascending direction relay 21 (not shown) that is turned on during ascending operation, and 22 ₂ is a normally open contact of the descending direction relay 22 (not shown) that is turned on during descending operation.

By detecting welding or poor contact of the main contact of the pole number switching contactor 16 by the method shown in FIG. 3, and by opening the normally closed contact _16T3 of the detector 16T, is no longer able to be loaded, the elevator stops, and the indicator light L is turned off to notify of the abnormality.
lights up.

According to the present invention, welding and poor contact of the contacts of the pole number switching contactor are detected, and the elevator is stopped.
Additionally, an indicator light can be turned on to notify maintenance personnel of this fact.

[Brief explanation of the drawing]

Fig. 1 is the main circuit diagram of the present invention, Fig. 2 is a time chart of Fig. 1, Fig. 3 is a contact abnormality detection circuit diagram of one embodiment of the present invention, and Fig. 4 is another embodiment of the present invention. FIG. 3 is a contact abnormality detection circuit diagram. 13... Contactor for high speed operation, 11... Contactor for rising operation, 14... Contactor for low speed operation, 12...
Contactor for descending operation, 15... Contactor for DC braking,
16...Contactor for switching the number of poles, 16T...Contact abnormality detector, FFB...Circuit breaker, FFBC...Trip coil for the edge breaker FFB.

Claims (1)

[Scope of utility model claims] In an elevator that is equipped with a three-phase AC power supply and a two-speed three-phase induction motor that has a high-speed side terminal and a low-speed side terminal and switches the number of poles with a single winding, and that operates at high or low speed, the three-phase induction motor A high-speed operation switching means that closes a circuit to supply power from a phase AC power source to a high-speed terminal of the three-phase induction motor, and a low-speed terminal of the three-phase induction motor at the same timing as the closing of this high-speed operation switching means. A switching means for switching the number of poles that short-circuits and changes the number of poles by changing the single winding from a triangular connection to a star connection, and the logic of the opening and closing states of the switching means for high-speed operation and the switching means for switching the number of poles. A control device for an elevator, comprising: means for detecting an abnormality; and means for cutting off power supply from the three-phase AC power source in response to the detecting means.