JPH0776550B2 - Instantaneous power failure automatic restart device for compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a momentary power failure automatic restart device for a compressor, and more particularly to a momentary power failure automatic restart device suitable for an AC device using an electromagnetic switch.

[Prior Art] Usually, an electric motor is used as a prime mover of a compressor, but a starting circuit is used because a large current is required to operate the electric motor. In the conventional direct-entry start method, as shown in FIG.
Is excited, the main circuit 11 is closed, the electric motor 12 is operated, and the auxiliary contact 13 self-holds to continue the operation. When stopping, the electromagnetic switch 5 is demagnetized by the stop switch 14 to open the main circuit 11 and stop the electric motor 12. As a starting method, for example, a reduced voltage starting, There are start-up and start-up compensator methods, but these also energize the electromagnetic switch 5 by the start-up switch 10 to close the main circuit 11 as in FIG. Reference numeral 15 is a thermal relay for the main circuit, and 16 is a fuse.

In this kind of starting circuit, when the power supply voltage drops abnormally due to the operation of another electric machine or lightning, or a momentary power failure occurs, the electromagnetic switch 5 is released and the main circuit 11 opens and the electric motor 12 It will stop. After such a stop due to power interruption, it is customary to manually restart the start switch 10. On the other hand, it has been proposed to automatically restart the system when a predetermined condition is satisfied in such a situation. This automatic restart device, as shown in FIG.
The restart preparation timer 6 and the restart command relay 8 are provided, and the restart preparation timer circuit includes a normally open selection switch 9 and an electromagnetic switch 5 for detecting that the power supply is energized. the normally closed contact 52C is inserted in series, whereas the restart command relay circuit re suction pressure of the compressor and the timer contact T ₃ to close a predetermined time during the oN operation of the restart preparation timer 6 shall apply below a specified value A protective pressure switch 7 is inserted in series that is turned on without any trouble in starting.

[Problems to be solved by the invention]

In the device shown in FIG. 3, after the operation is started by the start switch 10 (after the normally closed contact 52C is opened), the selection switch 9 is operated.
The restart preparation is completed by manually turning on.

That is, when the power is cut off in this state, the electromagnetic switch 5 is released, the electric motor 12 is stopped, and the normally closed contact 52C of the electromagnetic switch is closed. Therefore, when the power is restored in this state, the restart preparation timer 6 When excited, the timer 8 for restart command is excited to restart.

However, in the device shown in FIG. 3, as described above, not only is it necessary to manually operate the selection switch 9 at the time of start-up, but also the selection switch 9 is manually operated when the power supply is stopped normally. I have to let you. That is, if the selection switch 9 is not turned off before the operation stop operation is performed, there is a problem that even if the selection switch 9 is stopped once, the restart circuit operates to start the operation again.

As described above, the device of FIG. 3 requires manual operation at the time of starting and stopping, and therefore cannot be applied to a device for remote operation or automatic operation.

The present invention provides a compressor instantaneous restart automatic restart device capable of automatically restarting a compressor stopped by power recovery after an instantaneous power failure or normal voltage recovery after an abnormal voltage drop. The purpose is to

[Means for solving problems]

The automatic restart device for a momentary power failure of the compressor of the present invention is activated by a power check timer having a normally-closed contact and a normally-open contact, which operates after a short time set by turning on the power, and an input of a start switch of the compressor. An electromagnetic switch having a normally open contact and a key relay that is set by excitation of the electromagnetic switch and that is reset by closing the normally open contact when the set time of the power check timer elapses. Is closed, the normally open contact is closed when the magnetic switch is excited, and then the contact is kept closed within the set time even if the electromagnetic switch is demagnetized, and the normally open contact is closed when the keep relay is set. Connected to a series circuit of a contact, a normally closed contact of the power check timer, and a normally open contact of the off-delay timer, and prior to the operation of the normally open contact of the power check timer. A relay for confirming an instantaneous blackout having a normally-closed contact for making the reset circuit of the keep relay non-energized, and a restart command relay for instructing re-excitation of the electromagnetic switch by exciting the relay for confirming instantaneous blackout. A restart circuit, which excites the instantaneous power failure confirmation relay on condition that the keep relay is set and that power is restored within the set time of the off-delay timer, It is characterized in that the normally open contact of the relay is closed to re-energize the electromagnetic switch and restart the compressor.

[Action]

According to the above configuration, in the staircase where the power is first turned on, the normally open contact is closed and the keep relay is reset when the set time of the power check timer elapses. After that, when the start switch is turned on, the electromagnetic switch is excited and the compressor is operated, and the normally open contact of the keep relay and the off delay timer are closed to store that the operation state is entered.

In this state, if the power is temporarily cut off for some reason, the electromagnetic switch will be demagnetized and the compressor will stop.However, the off-delay timer will use the contact for the set time after the power is cut off. When the power is restored within the set time of the off-delay timer, the relay for momentary power failure confirmation is excited on condition that the keep relay is set and the power is restored within the set time. To restart.

When the power recovery is after the set time of the off-delay timer, even if the keep relay is set, the normally open contact of the off-delay timer is open, so the relay for momentary power failure confirmation is not excited and the compression The machine will not restart. Also, if you operate the stop switch while the power is normal, the keep relay will be reset, so the instantaneous power failure confirmation relay will not be excited even if the normally open contact of the off-delay timer is closed.
The compressor will not be restarted.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The instantaneous blackout automatic restart device of the present invention includes a determination circuit 100 that determines whether or not there is an instantaneous blackout, and operates the restart circuit 200 that outputs a restart command signal according to the output of this determination circuit. Is configured.

The determination circuit 100 is composed of a keep relay 1 that stores that the compressor has once entered an operating state, an off delay timer 2 and a power check timer 3 that operate for a predetermined time, and an instantaneous power failure confirmation relay 4. . The set operation coil 1a of the keep relay 1 is connected in parallel to the off-delay timer 2, the auxiliary contact 13B of the electromagnetic switch 5 is inserted in series in this parallel circuit, and the reset operation coil 1b of the keep relay 1 is electromagnetically opened and closed. The normally closed contact 13C of the device 5, the timer contact T _2A of the power check timer 3 and the relay contact T _{X1 which} is turned on when the momentary power failure confirmation relay 4 is demagnetized are inserted in series. In addition, the instantaneous switch confirmation relay circuit has an electromagnetic switch 5
And the relay contact 13D of, and keep the relay contact K _P to ON operation at the time of excisional of keep relay 1, the power supply check timer 3
When the power is detected, the normally-closed timer contact T _2B that continues ON operation for the set short time and turns OFF after the set time elapses, and the timer contact T ₁ that operates ON for the set time of the off-delay timer 2 Inserted in series and timer contact
A relay contact T _X3 for self-holding is provided in parallel with T ₁ and T _2B .

Then, the restart preparation timer circuit has a relay 4 for instantaneous power failure confirmation.
The normally open relay contact T _X2 is connected to the restart preparation timer 6, and the restart command relay 8 is controlled by the contact T _{3 of the} timer 6. The relay contact X of the restart command relay 8 is connected in parallel with the starting switch 10 and the self-holding contact 13A, and the ON / OFF operation of the contact X excites the electromagnetic switch 5 to start the electric motor 12 again. Let

Next, the operation of the above embodiment will be described with reference to FIG.

When the power is turned on for the first time, the power check timer 3 runs and the normally closed contact T ₂ B contact is turned on for the set time (0.5 seconds).
OFF the contact point T ₂ B After holding, to reset the keep relay 1 is closed timer contact T _2A after the lapse its set time at the same time. After that, when the start switch 10 is turned on, the electromagnetic switch 5 is excited, the auxiliary contact 13A is closed and self-holds, and the main contact 11 is closed to start the electric motor 12 to operate the compressor. At the same time, the auxiliary contact 13B of the electromagnetic switch 5 is closed and the off-delay timer 2 is set to the timer contact.
T ₁ is closed, and keep relay 1 is set, and relay contact K _P is closed. In this state, when a momentary power failure occurs on the power supply side, the electromagnetic switch 5 is demagnetized, the main contact 11 is opened to stop the electric motor 12, the auxiliary contacts 13A and 13B are opened, and the auxiliary contacts 13C and 13D are closed. On the other hand, the off-delay timer 2 has a set time (10 to 150
The timer contact T ₁ is held for 2 seconds), and the contact T ₁ is opened after the set time has elapsed. When the power is restored again during this set time, the keep relay 1 is in the set state, the keep relay contact K _P is closed, and the power supply check timer 3 is started, but the timer contact T of the timer 3 is started. _{Since 2B} is closed for the set time (0.5 seconds), the instantaneous power failure confirmation relay 4 is energized via the auxiliary contact 13D of the electromagnetic switch 5, the keep relay contact K _P , and the relay contacts T _2B and T _1. , Self-held by the relay contact T _X3 . When this instantaneous power failure confirmation relay is excited, the relay contact T _X2 is closed and the restart preparation timer 6 is started. This timer contact T ₃ is closed after the set time (5 seconds) has elapsed. During this time, the set time of the power check timer 3 has elapsed and the timer contact T _2A is closed, but since the instantaneous power failure confirmation relay 4 is ON before that, the relay contact T _X1 is opened. Therefore, the reset side coil 1b of the keep relay 1 is not energized, the keep relay 1 is kept in the set state, and the relay contact is kept.
K _P is closed. If the timer contact T ₃ is closed and the pressure of the compressor is below the specified value and the protective pressure switch is closed, the restart command relay 8 is connected via the timer contact T _3.
Is energized. When the restart command relay 8 is excited,
The relay contact X is closed, the electromagnetic switch 5 is energized, and the main contact
11 is closed, the electric motor 12 is started, and the compressor is operated again.

Further, at the time of a normal stop with the power source present, the electromagnetic switch 5 is de-energized by the operation of the stop switch 14 and the auxiliary contact 13D is closed, but the keep relay 1 is reset and its normally open contact K _p Since the off-delay timer 2 is open within the set delay operation time, the timer contact T ₁
Even if is closed, the circuit of the relay 4 for instantaneous power failure confirmation is not formed. Therefore, the relay 4 for instantaneous power failure confirmation is not excited, the restart preparation timer 6 is not driven, and the compressor is not restarted. On the other hand, when the power is turned on at the next startup, the power check timer 3 is started, and after the set time has elapsed, the timer contact T _2A is closed and the reset side coil is energized, the keep relay 1 is reset, and the relay contact is reset. K _P is opened.

Here, an air timer is used as the off-delay timer 2, and this air timer has a structure that sucks air during excitation and holds the contact for a set time even after demagnetization. Normally, the off-delay timer 2 has a set time of 10 to 150 seconds, but there are some that have a long set time.
The power check timer 3 sets a predetermined short time period during which the keep relay 1 can be reset between the power-on and the starting operation, and the momentary blackout confirmation relay 4 can be excited at the momentary blackout after activation. The restart preparation timer 6 adjusts the set value according to the characteristics of the machine.

Although the protective pressure switch 7 is provided in the above embodiment, this pressure may be air pressure, hydraulic pressure, water pressure, etc. depending on the type of compressor or the system including the compressor. Alternatively, a temperature relay or the like can be used. Further, the relay contact X of the restart command relay 8 is inserted at the same position as the start switch 10, but it is not limited to this, and the timing relationship with the electromagnetic switch 5 and its auxiliary contacts 13A to 13D. Thus, the positions of the relay and the electromagnetic switch can be changed, and the restart command relay 8 can be replaced by a timer.

〔The invention's effect〕

As described above, according to the present invention, the compressor stopped at the momentary power failure can be automatically restarted, so that the work at the momentary power failure is reduced and the efficient operation can be performed.

[Brief description of drawings]

1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the embodiment shown in FIG. 1, FIG. 3 is a restart circuit diagram by manual operation, and FIG. [Fig. 4] is a start-up circuit diagram of a compressor. 1 ... Keep relay, 2 ... Off delay timer, 3 ...
… Timer for power check, 4… Relay for momentary power failure confirmation, 6
…… Restart preparation timer, 8 …… Restart command relay.

Claims (1)

[Claims] 1. A timer for power supply check, which operates after a short time set by power-on and has a normally closed contact and a normally open contact, an electromagnetic switch excited by an input of a start switch of a compressor, Set by exciting the electromagnetic switch,
A keep relay that closes and resets the normally open contact when the set time of the power check timer elapses, and a normally open contact that closes the normally open contact when the electromagnetic switch is excited, and then the electromagnetic switch. Is demagnetized, an off-delay timer that keeps the contact closed for a set time, a normally-open contact that closes when the keep relay is set, a normally-closed contact of the power check timer, and the off-delay timer A relay for momentary power failure connected to a series circuit with a normally-open contact, and having a normally-closed contact that opens prior to the operation of the normally-open contact of the power supply check timer to de-energize the reset circuit of the keep relay; A restart circuit having a restart command relay for commanding the re-excitation of the electromagnetic switch by exciting the instantaneous power failure confirmation relay, and the keep relay is set. And, on condition that power is restored within the set time of the off-delay timer, the instantaneous power failure confirmation relay is excited, the normally open contact of the restart command relay is closed, and the electromagnetic switch is re-excited. Then, the automatic restart device for the instantaneous blackout of the compressor, which is configured to restart the compressor.