JPS587593B2 - DC elevator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for a DC elevator, and more particularly to a control device suitable for emergency braking in the event of power loss in an ultra-high-speed elevator.

Conventionally, DC elevators have been used as shown in Figure 1.
A hanging weight 2 is hung on a sheave 4 by a drive rope 3, and the sheave 4 is driven by a DC motor 5.

The speed of the DC motor 5 is controlled by exciting the excitation winding 7 of the DC generator 6 constituting a Ward Leonard circuit with a speed index cooling device 8.

The field winding 9 of the DC motor 5 is excited by an exciter 11 that is directly connected to a three-phase induction motor 10 that drives the DC generator 6, and is connected to a limiting resistor 12 and an electromagnetic contactor 1.
3, a predetermined field current is maintained during elevator operation.

By the way, the exciter 11 is a self-excited DC generator, and the excitation winding 14 of the exciter is connected in series with an adjustment resistor 15 and connected to both terminals of the exciter.

As shown in Fig. 2, the excitation characteristic becomes stable at the intersection P1 of the excitation characteristic A at the rated rotation speed and the resistance line R.
The exciter automatically rotates when the three-phase induction motor 10 rotates.
1 voltage is generated.

In the DC elevator control circuit with the above configuration, power outages or F/F of the elevator power supply are detected while the elevator is running.
・When the power is lost with B (fuse free breaker) 17 tripped, the entire elevator control circuit becomes uncontrollable, so the emergency stop relay 18 is demagnetized.
The excitation winding 7 of the DC generator 6 is short-circuited.

As a result, the voltage generated by the DC generator 6 becomes smaller than the back electromotive force of the DC motor 5.
The inertial energy of all elevators, including , is regenerated to the DC generator.

However, since we are now assuming a power outage or a tripped state of FFB 17, the energy will not be regenerated to the 3φ power source, and the rotation speed of the motor generator consisting of exciter 11 13-phase induction motor 10 + DC generator 6 absorbed by an increase in

Elevator speed is 150 m/min ~ 300r
Up to about n/min, the total inertial energy of the elevator is not so large, and the increase in the rotational speed of the motor generator is small.

However, when it comes to ultra-high-speed elevators in the 400 to 500 m/min class, inertial energy increases in proportion to the square of the speed, so the regenerated energy also increases, and the motor generator rotation speed also increases from 120 to 120 m/min of the rated rotation speed. It increases to about 150%.

Therefore, the rotational speed of the exciter increases in proportion to it, and the excitation characteristic becomes like curve B shown by the broken line in Fig. 2, and the output voltage of the exciter is plotted on the vertical axis at the intersection point P1 with the resistance line R. A certain V1
increase to.

As a result, the current flowing through the field winding 9 of the DC motor 5 increased proportionally, and the regenerated power torque exceeded the slipping limit torque of the rope 3 and sheave 4, resulting in a dangerous rope slipping phenomenon.

An object of the present invention is to eliminate the above-mentioned drawbacks and to reliably bring a high-speed elevator to an emergency stop even in the event of power loss such as a power outage or F.F.B. trip.

A feature of the present invention is that power loss and elevator speed are detected to suppress the excitation voltage of the field winding by the exciter.

Next, a specific example of the present invention will be explained with reference to FIG.

The configuration of FIG. 3 is roughly the same as the conventional control circuit of FIG. 1, and the same components are given the same numbers, so a description thereof will be omitted.

The difference from FIG. 1 is that a power supply detection relay 19 is installed at the input of the Sanwa induction motor for power supply voltage detection, and the normally open contact 19-1 of the voltage detection relay 19 is connected to the governor contact for speed detection. 20, and as shown in the figure, a part of the adjusting resistor 15 for the exciter winding current of the exciter is short-circuited.

By doing this, when the elevator loses power while running at high speed and an emergency stop is applied, the normally open contact 19-1 of the power detection relay 19 will open, and since the speed is high, the governor contact 20 will also open. Therefore, the value of the adjustment resistor 15 increases, and the resistance line that determines the voltage generated by the exciter changes from R to S, as shown in FIG.

Therefore, even if the rotational speed of the motor generator increases due to the regeneration of the inertial energy of the elevator, the voltage generated by the exciter remains at the vertical axis v1 of the intersection P1 of the curve B and the resistance line S. 2 can be brought to the same level as the voltage V1 generated during normal operation, and as a result, the field winding current of the DC motor 5 can also be maintained at a predetermined value, preventing abnormalities in regenerative power torque. It is possible to prevent the rope slipping phenomenon caused by an increase in the number of ropes.

In Fig. 3, as a means to suppress the voltage generated by the exciter, a regulator contact for detecting the speed of the elevator is inserted into the exciter excitation winding current regulating resistor, but a contact for detecting the rotation speed of the motor generator Even if you replace it with , the same effect will occur.

[Brief explanation of the drawing]

Fig. 1 is a conventional DC elevator control circuit diagram, Fig. 2 is a characteristic explanatory diagram of a conventional exciter machine, Fig. 3 is a DC elevator control circuit diagram of the present invention, and Fig. 4 is an excitation machine diagram of the present invention. FIG. 1...Cage, 2...Hanging weight, 3...Drive opening, 4
... Sheave, 5 ... DC motor, 6 ... DC generator, 7 ...
... Excitation winding, 8 ... Speed command device, 9 ... Field winding, 1
0...Three-phase induction motor, 11...Exciter, 12...Limiting resistor, 13...Magnetic contactor, 14...Exciting winding, 15...
...Adjustment resistor, 16...Starting contactor, 17...F・F・B
, 18...Emergency stop relay, 19...Power detection relay,
20...Governor contact.

Claims (1)

[Claims] 1. In a DC elevator controlled by a Ward Leonard circuit, in which the field winding of the DC motor driving the elevator is excited by an exciter directly connected to an electric generator, when the power is lost, the above-mentioned A control device for a DC elevator, comprising means for suppressing the excitation voltage of a field winding.