JPS598132B2 - 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, M1, M2...Mn-
1. Mn is an electric motor as a load, 521, 522, 52
(n-1) 52n is a main circuit contact of an electromagnetic switch provided corresponding to these motors. FIG. 2 is a diagram showing a conventional calm control device for one of the motor groups, where R, S, and T are the lines of the main circuit power supply 1, M is the motor, and 52C is the operating coil of the electric switch. When this is excited, the main circuit contact 52 is closed and the electric 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 motor's on/off switch, ER,
ET is a controlled power source. In such a configuration,
If the main circuit power supply 1 is active, switch PBS
When is pressed, the operating coil 52C of the electromagnetic switch is energized, the main circuit contact 52 is closed, and the electric motor M is started.

On the other hand, at this time, the auxiliary contact 52-a of the electromagnetic switch becomes 0N, so even if the "on" switch PBS is released, the electric motor M
continues driving. If the power supply 1 were to fail in such a state, the electromagnetic switch would lose its self-holding state, its main circuit contact 52 would open, and the motor would stop; The timer T is kept in the operating state, and when the power is restored before the capacitor C finishes discharging, the operating coil 52C of the electromagnetic switch is energized through the contact Tc of the timer T, which has a built-in momentary interruption relay, and the main circuit contact 5
2 closes 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, the conventional power failure recovery starting device restarts the motor M1 that has been operating until the power is restored.
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 has been made with the aim of solving the above-mentioned drawbacks, and by starting the motor groups sequentially when the power is restored and preventing restarting if the power is restored later, the voltage at the time of starting can be reduced. To provide a load start control device that can reduce the drop, reduce the size of power supply equipment, and prevent restart in a dangerous state.

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

Figure 3 shows each declaration. 1 of the electric motor group provided corresponding to the motor
The control circuit for each machine is shown, and FIG. 4 shows the 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 motor, subscripts 1, 2, . . . m, etc. are added after the reference numerals.
It is marked with n. ER and ET are AC 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, and KP is a latch relay that memorizes the operating status of the motor. , KPC?・The closing coil of the latch relay is connected to the control power supply ER, ET via the normally open contact 52-a of the magnetic switch, and KPT is the normally closed contact 52-b of the electromagnetic switch and the auxiliary timer described later. Control power supplies ER and E are connected to the control power sources ER and E through a parallel circuit between the time-limited operation contact 2-T of the relay 2 and the time-limited operation contact TA-T of the timer TA.
This is the tripping coil of the latch relay connected to 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,K
P-b is the normally open contact and normally closed contact of the latch relay KP,
Reference numeral 2 denotes an auxiliary time relay that prevents the electromagnetic switch from malfunctioning when the power is restored, and the normally open contact 52-a of the electromagnetic switch and time relays T1 to Tn that set the sequential start of the motor shown in Fig. 4. It is connected to the control 1 power source ER, ET via a parallel circuit with the previous contact Tm-T. The normally open contact 2-a of the auxiliary time relay 2 is the normally open contact K of the latch relay.
It is connected in series with P-a, and in parallel with the normally open contact 52-a, which is a self-holding contact of the electromagnetic switch.

84 is a voltage detection relay that detects the presence or absence of voltage of the main circuit power supply 1; -a is its normally open contact, 84-b is its normally closed contact, Tl, T2...Tn are relays connected to the uninterruptible control power supplies BP, BN via the normally open contact 84-a. Set the starting order of the motor groups.

Time-limited operation contacts Tm-T of these time relays T1 to Tn
are connected in series with the auxiliary time relays 2 of each control circuit shown in FIG. Incidentally, assuming that the electric motors are started in the order of the subscripts, the time relay T1 corresponding to the l-th electric motor that is started first is directly connected to the uninterruptible misaki power supplies BP and BN via the contact 84-a, In addition, the time relay T2 corresponding to the second motor connected connects the normally open contact 521-a of the electromagnetic switch of the control circuit corresponding to the first motor and the normally open contact KPl-b of the latch relay. It is connected to control power supplies BP and BN via a parallel circuit. Similarly, the time relay Tn corresponding to the nth motor started is connected to the normally open contact 52(n-1)-a of the electromagnetic switch corresponding to the n-1st motor just before it and the latching relay Tn. It is connected to the control power supplies BP and BN via a parallel circuit with the normally closed contact KP(n-1)-b. TA is a timer connected to the power supplies BP and BN through the normally closed contact 84-b of the voltage detection relay. -T
is turned ON and all latch relays KP are tripped to prevent the electric motor M from restarting. In such a configuration, first, in FIG. 3, the "on" switch PBS
When the switch is operated, the moving coil 52C of the electromagnetic switch is energized and self-maintained by the normally open contact 52-a parallel to the "on" switch, and at the same time, the main circuit contact 52 becomes 0NL 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 of the latch relay
-a is 0N, 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, when the main circuit power supply 1 is out of power, the self-holding of the electromagnetic switch 52C is released and the auxiliary normally open contact 52-a is turned 0FF, but the contact KP-a of the latch relay is 0N and the contact KP-b is 0FF. hold.

In Fig. 4, when the main circuit power supply 1 is restored within a certain period of time and its voltage exceeds a certain value, the voltage detection relay 84 operates, its normally open contact 84-a becomes 0N, and first the time relay T1 is energized. be done. After a certain period of time, the contact T1-T [Tm-T in Figure 3] of the time relay becomes 0N, the auxiliary time relay 2 is energized, and the electromagnetic signal is generated through the instantaneous contact 2-a and the contact KP-a of the latch relay. The operating coil 52C of the switch is energized and self-maintained, and the first electric motor is started. When the first electric motor is started, the contact 521-a shown in FIG. 4 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 motor was not running before the power failure, the latch relay contact KPl-BV shown in Figure 4
3. Since it is turned on, when the power outage is restored, the second electric motor will start. Therefore, the first to nth motors that have not been operated will not start even if the power is turned back on, and the starting time is omitted, so the time required to start all the motors is shortened.

Furthermore, if the recovery from the power outage is prolonged, the set time of the timer TA shown in Figure 4 has passed and even if the power is restored, the circuit of the reset relay KP shown in Figure 3 will not operate through the contact 52-b and the time limit contact TA-T. Excite the tripping coil KPT and set its contact KP-a to 0.
For FF, contact Tm- of T1-Tn
Even if T becomes 0N, the electric motor M will not start.

As described above, when the motors that were in operation are started sequentially when the power is restored, the inrush current at the time of starting is suppressed.
Therefore, the power supply capacity becomes smaller and the cost becomes lower.

Also, there is no waiting time for starting, so you can start operating quickly. Furthermore, if the power outage is prolonged, restarting of the motor can be prevented, and there is no danger. In the above example, the sequential starting of each motor was explained, but if the capacity of the motor is... For example, several units 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.

In addition, in order to prevent malfunction when the power is restored, in other words, an auxiliary time relay 2 having a time-limiting contact 2-T is installed so that the latch relay KP is tripped after the main circuit contact Ω of the electromagnetic switch has operated reliably. 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.
It is sufficient to provide a time-limiting contact Tm-T of ~Tn. As described above, in this invention, each electromagnetic switch is driven once based on the starting signal from the time relay that sets the load starting order and the operating status of the load before the power outage. Loads that have been in operation can be started one after another, reducing the power supply capacity of the main circuit.

Furthermore, if the power outage does not return too late, the timer is used to cancel all the load operating conditions before the power outage and prevent a restart, which is also effective in terms of safety.

[Brief explanation of drawings]

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 cooling device provided for each load, and Figs. 3 and 4 are diagrams showing the invention. This is a circuit diagram of a control device showing one example. Fig. 3 shows a control circuit provided for each load, and Fig. 4 shows a control circuit provided in common to all loads. show. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A plurality of loads connected to the main circuit power supply through contacts of electromagnetic switches, a voltage detection relay that detects the voltage of the main circuit power supply, and a voltage detection relay connected to the uninterruptible control power supply and configured to detect the voltage a first control circuit comprising a timer for detecting a power return delay that operates when the detection relay does not detect voltage for a predetermined time; and a time relay that sets the starting order of the plurality of loads when the voltage detection relay detects voltage. , a latch relay that is connected to the control power supply corresponding to each of the loads and stores the operating state of the load before the power outage until the timer for detecting delay in power return is activated, and the state of the latch relay and the above. A load starting control device comprising a second control circuit including a coil of the electromagnetic switch which is operated based on a starting signal from a time relay. 2. The number of time relays corresponding to the loads is provided, and the time relay for the nth load starts between the auxiliary normally open contact of the n-1st electromagnetic switch and the normally closed contact of the n-1st latch relay. A load starting control device according to claim 1, characterized in that the device is operated via a parallel circuit. 3 A plurality of loads each connected to the main circuit power supply through 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 uninterruptible control power supply, and the voltage detection relay detects the voltage for a predetermined period of time. a timer for detecting a power return delay that operates when the voltage is not detected, and a time relay that sets the starting order of the plurality of loads when the voltage detection relay detects voltage, corresponding to each of the loads. and a latch relay that is connected to the control power source and stores the operating state of the load before the power outage until the timer for detecting delay in power return is activated, and the state of this latch relay and the start signal from the time relay. A load starting control device comprising a second control circuit consisting of a coil of the electromagnetic switch that is operated based on the above, and an auxiliary time relay that trips the latch relay later than the operation of the electromagnetic switch. .