JPS5944859B2 - Load starting control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the starting of a load, such as an electric motor, at the time of recovery from a power outage.

Figure 1 shows load equipment to which this invention is applied.
In the figure, 1 is the main circuit power supply, M, , M2...
Mfl-, , Mn are electric motors as loads, 521, 52
2... 52(n-1) and 521 are main circuit contacts of electromagnetic switches provided corresponding to these motors.

FIG. 2 is a diagram showing a conventional control device for one motor group, where RS-T indicates each line of the main circuit power supply 1, M indicates the motor,
52c is an operating coil of an electromagnetic switch, and when this is excited, the main circuit contact 52 is closed and the motor M starts rotating.

52-a is its auxiliary contact, T9 is an instantaneous power failure relay, and the time relay T is held for a predetermined time by discharging the capacitor C during a power failure.

PBS, PBT is the electric motor's "off" switch, ER
, ET is a control power source. In such a configuration, when the main circuit power supply 1 is active and the "human" switch PBS is pressed, the operating coil 52C of the electromagnetic switch is energized, the main circuit contact 52 is closed, and the motor M is started.

On the other hand, at this time, the auxiliary contact 52-a of the electromagnetic switch is ON (
Even if the switch PBS is released, the electric motor M
continues driving. If the power supply 1 goes out in such a state, the electromagnetic switch loses its self-holding state, its main circuit contact 52 opens, and the motor stops, but the instantaneous power failure relay T9 stops due to the internal capacitor C discharging The timer T is held in the operating state. If the power is restored before the capacitor C finishes discharging, the operating coil 52C of the electromagnetic switch is energized through the contact Ic of the timer T with a built-in instantaneous power failure relay, and the main circuit contact 52 is closed and the motor starts again. The above description has been about one motor, but normally the power supply equipment is as shown in FIG. 1, so when the power is restored, all the electric motors M that have been operating up until now are started all at once. As described above, when the power is restored, the conventional power failure recovery starting device restarts the motor M1 that has been operating until now.
Since ~Mn starts all at once, the capacity at the time of starting increases and the voltage drop becomes large.

In order to reduce the voltage drop during startup, it is possible to increase the power supply capacity, but increasing the power supply capacity has become economically expensive. This invention was made with the aim of eliminating the above-mentioned drawbacks, and it is a load that can reduce the voltage drop at the time of starting and reduce the size of the power supply equipment by starting the motor groups sequentially when the power is restored. A starting control device is provided.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3 shows a control circuit for one motor group provided corresponding to each motor, and FIG. 4 shows a control circuit provided in common to the motor group. In the figure, the same reference numerals as in Fig. 2 indicate the same parts, and when corresponding to a specific electric motor, a subscript (1, 2,...m...
...n) is attached. EB and ET are AC control power supplies that are not uninterruptible power supplies. 52-A and 52-b are the normally open and normally closed contacts of the electromagnetic switch, respectively. KP is a latch relay that remembers the motor's on/off status, and KPC KPT is the closing coil of the latching relay connected to the control power sources ER and ET via the normally open contact 52-a of the electromagnetic switch, and KPT is the normally closed contact 52-b of the electromagnetic switch and the auxiliary time relay 2 to be described later.
This is the tripping coil of the latch relay connected to the control power sources ER and ET via the time-determined operation contact 2-T. Note that this latch relay KP is interlocked with each other so that only either the closing coil KPC or the tripping coil KPT operates. KP-A, KP-b
are the normally open and normally closed contacts of latch relay 1 KP, and 2 is an auxiliary time relay that prevents the electromagnetic switch from malfunctioning when the power is restored. Time relay T1 to set sequential start
It is connected to the control power sources EB, , ET via a parallel circuit with the time-determined operation contacts Tm-T of Tn. The normally open contact 2-a of the auxiliary time relay 2 is the normally open contact KP-a of the latch relay.
The normally open contact 52-a, which is a self-holding contact of the electromagnetic switch, is connected in series with the normally open contact 52-a. 84 is a voltage relay that detects the presence or absence of voltage of the main circuit power supply 1, 84-a is its normally open contact, T, T2...h are normally open contacts 84
The starting order of the motor group is set by a time relay connected to the control power supplies VB, VT through -a.

Time-limited operation contacts Tm-T of these time relays T1 to Tn
are connected in series with the auxiliary time relay 2 of each control circuit shown in FIG. Incidentally, assuming that the motors are started in the order of the subscripts, the time relay T1 corresponding to the motor started first is directly connected to the control power supplies R and VT via 84-a, and The time relay T2 corresponding to the motor to be started is connected via a parallel circuit between the normally open contact 521-a of the electromagnetic switch of the control circuit corresponding to the first motor and the normally closed contact KPl-b of the latch relay 1. and connected to control power supplies VR and VT. Similarly, the time relay Tn corresponding to the nth motor started is the first time relay Tn.
The normally open contact 52(n-,)-a of the electromagnetic switch corresponding to the previous n-1th motor and the normally closed contact KP of the latch relay.
(n-1)-b via a parallel circuit with the control power supply VB,,
connected to l. In addition, the control power supply VR, V shown in FIG.
T may be shared with the control power supplies ER and ET shown in FIG. 3, or may be a separate power supply. In such a configuration, as shown in FIG. 3, when the "on" switch PBS is operated, the operating coil 52C of the electromagnetic switch is energized, and the normally open contact 52-a in parallel with the "on" switch turns off the self. At the same time, the main circuit contact 52 turns ON and the motor starts operating. On the other hand, the closing coil KPC of the latch relay is energized by the auxiliary normally open contact 52-a of the electromagnetic switch and is mechanically maintained in that state. Therefore, in this state, the normally open contact KP-a of the latch relay is 0N1, the normally closed contact KP-b is 0FF, and it is remembered that the motor was in operation. This condition continues as long as the tripping coil KPT of the latch relay is not energized. Now, if the main circuit power supply 1 has a power outage, the electromagnetic switch 52
The self-holding of C is released, and the auxiliary normally open contact 52-a turns 0FF, but the latch relay's contact KP-a becomes 0N1 contact KP-b.
holds the state of 0FF.

When the main circuit power supply 1 is restored and its voltage exceeds a certain value, the voltage detection relay 84 operates and its normally open contact 84-a
turns ON, and time relay T1 is first energized. After a certain period of time, contact T1-T of the time relay [T in Figure 3]
m-T] becomes 0N, the auxiliary time relay 2 is energized, and the operating coil 52C of the electromagnetic switch is energized and self-maintained through its instantaneous contact 2-a and the contact KP-a of the latching relay 1, and the first motor is activated. starts. When the first electric motor starts, the contact point 521-a shown in FIG. 1 is turned ON, so that the time relay T2 is energized. Thereafter, the same operation is repeated to start the nth electric motor. If the first electric motor is not in operation before the power outage, the latch relay contact KPl-b in FIG. 4 is set to ON, so when the power outage is restored, the second electric motor will start. Therefore, the first to nth electric motors that have not been operated will not start even when the power is restored, and the starting time is omitted, so the time required to start all the electric motors is shortened. In addition, even if the power outage is prolonged, when the power is restored, contact Tm-T
Since the current becomes 0N, the electric motor performs the operation described above and starts in sequence.

As mentioned above, when a power outage returns, the motors that have been in operation are started sequentially, so the inrush current at the time of starting is suppressed.
Therefore, the power supply capacity becomes small and the cost becomes low. Also, since there is no waiting time for starting, you can get started quickly. In the above embodiment, sequential starting of each motor was explained, but if the capacity of the motor is small, several motors may be started as a group. Further, in the above embodiment, the case where an electric motor is used as the load has been described, but the same effects as in the above embodiment can be obtained also in the case of an electric spring closing type opening/closing device.

Further, in order to prevent malfunction when the power is restored, that is, after the main circuit contact 52 of the electromagnetic switch has operated reliably, an auxiliary time relay 2 having a time-limited operation contact 2-T is provided so as to trip the latch relay KP. However, if the electromagnetic switch itself can achieve time coordination in this respect, the auxiliary time relay 2 may be omitted.

In that case, the time relay T1 sets the starting order at the position where the instantaneous contact 2-a of the auxiliary time relay 2 is provided.
-Tn time-limiting contacts Tm-T may be provided. As described above, in this invention, each electromagnetic switch is driven by the starting signal from the time relay that sets the load starting order and the operating state of the load before the power outage, so when the power outage returns,
Loads that have been in operation can be started one after another, which is effective in reducing the power supply capacity of the main circuit and restarting unmanned equipment.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of load equipment to which the present invention is applied, FIG. 2 is a circuit diagram showing a conventional control device provided for each load, and FIGS. 3 and 4 are one example of the present invention. A circuit diagram of a control device showing an embodiment. FIGS. 2 and 3 show a control circuit provided for each load, and FIG. 4 shows a control circuit provided commonly to all loads. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Multiple loads each connected to the main circuit power supply via the contacts of an electromagnetic switch, a voltage detection relay that detects the voltage of the main circuit power supply, and a voltage detection relay connected to the control power supply, when the voltage detection relay detects the voltage. A time relay that sets the starting order of the plurality of loads mentioned above, a latch relay that is provided corresponding to each of the loads and stores the operating state of the load before the power outage, and the state of the latch relay and the time relay A start control device for a load, comprising: a coil of the electromagnetic switch that is activated based on a starting signal; a control power source that operates the latch relay; and the coil of the electromagnetic switch.