JPH01270720A - Automatic reset type overload protection relay - Google Patents

Abstract

PURPOSE:To improve load operability by providing a number-of-resets storage circuit for storing whether a resetter is reset or not after a circuit breaker is initially set and reset when the set continuing time of the breaker exceeds a predetermined time. CONSTITUTION:A relay determines, when a circuit breaker 3 is opened, a time for reclosing it according to the number of reset signal generations of a resetter 7. That is, first reset corresponding to a temporary overload in which two resets are not normally continued is rapidly conducted for a fixed predetermined time, second reset or later is conducted after a relatively long time to be altered according to the property of its load. Thus, if the initial reset of a motor 1 and a reset continuing time by a counter 10 for counting the reset continuing time of the breaker 3 exceeds a predetermined time, a number-of-reset storage circuit 9 is so reset as to handle in the same manner as that when the breaker 3 is initially reset. Thus, it is rapidly reset at the time of temporary overload to improve load operability.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention detects a negative (blue overload) load state of a motor, etc., and shuts off a cutoff part when this overload state continues for a predetermined time or more. , relates to an automatic reset type overload protection relay that closes the interrupting part again after a predetermined reset time has elapsed.

[Conventional technology]

The third conventional automatic '4Sl return 1nft load protection relay.
The one shown in the figure is known. In FIG. 3, a motor l is connected to a power source via a current transformer 2 and a cutoff section 3. In FIG. The automatic reset type overload protection relay has a signal generation circuit 41.
Operating time setting circuit 5. Cutoff circuit 6゜Return circuit 7. A return time setting circuit 8 is provided.

The output terminal of the current transformer 2S2 is connected to the signal generation circuit 4, and when the output of the temperature changer 2 indicates an over-r11 odd state, the voltage generation circuit 4 starts the predetermined counter time set by the operation time setting circuit 5. It emits an overload r41b due to its characteristics. 1. No. 1 generation circuit 4° is 2
It has two output ends, one of which is connected to the cutoff circuit 6. When this circuit 6 receives overload No. 48, it sets the output storage circuit 6a provided therein and also closes the circuit 3.

Further, the other output terminal of the signal generating circuit 4 is connected to a cutoff circuit 6 via a return circuit 7. After receiving the load signal, the return circuit 7 issues a return signal after a predetermined return time set by the return time setting circuit 8 has elapsed, resets the output storage circuit 6a, and returns the cutoff circuit 6. When the cutoff circuit 6 is restored, the cutoff section 3 is turned on. In other words, in this relay, when a load such as a motor becomes overloaded A and overheats, the power supply to the load is temporarily cut off, and during this time the excess F+ load is removed and the relay is cooled down, so that it can be started again.
'n and rq are automatically connected to the power source and can continue to operate.

[Problem to be solved by the invention]

When an overload condition occurs, this relay is removed in a short period of time.Even if it is a so-called temporary overload, once the cut-off section is cut off, a relatively long set recovery time will elapse. There was a problem in that it was not possible to turn on the cutoff section again and restart the load until later. Also, due to noise and surge coming from the power supply, this Il! Even in the event that an electrical appliance malfunctions and shuts off the cut-off section, it takes a relatively long set recovery time until the cut-off section is turned on again.
There was a problem that the load operation rate decreased.

An object of the present invention is to provide a temporary overload R-? ) If it is shut off due to malfunction, turn it on again quickly, and turn on f4. only when it is determined that an overload has definitely occurred. An object of the present invention is to provide an automatic reset type overload protection relay that can be reloaded after a cooling period for a load and suppresses a drop in load operation rate.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention includes a cutoff circuit that cuts off a cutoff section by an overload 4 blue signal issued from a signal generation circuit in response to an overload current, and a recovery time setting circuit after the overload signal is input. In the automatic reset type overload protection relay, the automatic reset type overload protection relay is equipped with a reset circuit that issues a reset signal after a set predetermined time has elapsed to reset the cutoff circuit and re-close the cutoff section, wherein the reset time setting circuit is configured to set a fixed time. variable time 2
At the same time, it stores whether the IsL return signal is a first signal or a second or subsequent signal, and stores n:1 in the return circuit.
Select the two-step setting time set in the return time setting circuit (a return number storage circuit that supplies No. 8 and a timing circuit that measures the duration of the closing section 41 are provided to store the number of return times). The circuit is configured such that the stored contents are set to the initial storage state of No. 4δ when the load is applied and when the continuous application time measured by the clock circuit exceeds a predetermined time.

[Effect]

This 8a electric current 2= is a temporary phenomenon that does not occur twice in a row by determining the time to turn it on when the interrupter is cut off, ul, and the number of times the return circuit generates the return circuit. The first time, which corresponds to an overload of When the load is first turned on and the timer circuit that measures the continuous time of turning on the breaker section exceeds a predetermined time, the number of times the breaker is returned is treated as the same as when it was first turned on. By resetting the memory circuit, the load can be quickly re-energized at 1 o'clock to improve the load operation rate.

[Embodiment] Fig. 1 shows an embodiment of an automatic reset type overload protection relay according to the present invention. Here, the same parts as in Fig. 3 are given the same reference numerals as in Fig. 3. In FIG. 1, motor 1j
Yohen residue 2. It is connected to the power supply via the a-disconnection section 3.

The automatic reset type overload protection relay has a signal generation circuit 4 similar to the conventional one. Operating time setting circuit 5. A cutoff circuit 6 with an output storage circuit 6a. Return circuit 7. It is equipped with a return time setting circuit 8 and is connected in the same way as the conventional one, but differs from the conventional one in that it is also provided with a return number storage circuit 9 and a clock circuit 1O. And return time setting circuit 8
The recovery time can be set in two stages: a fixed relatively short time and a variable relatively long time. The reset number memory circuit 9 is a reset output from the clock circuit 10 (reset by No. 3) when the clock circuit 1G (7) is first activated and when the clock time Ta of the clock circuit 10 becomes longer than the predetermined time Ta. This return number memory circuit 9 outputs L (low level) in the reset state and 1 ((high level) output (No. 3 S&) in the set state to the return circuit 7. is the output (3
When the return circuit 7h) outputs the return signal S after the cutoff section 3 is cut off by the overload signal S issued from the signal generation circuit 4 in the state of No. ■, the return circuit 7 outputs the return signal S Set signal S? Set by.

The return time WR7 is the output signal S4 from the return number storage circuit 9.
When is L, it is a fixed relatively short time Tr.

When the output signal from the return number storage circuit 9 is 11, the return signal Ss is generated at a variable and relatively long time Tr2.

The clock circuit 10 measures the duration of closing of the cutoff section 30, and when the motor 1 is first turned on, the reset circuit 7 receives the reset signal S.
When the breaker circuit 6 disconnects the breaker 3, the clock is stopped by the output stop signal SS. No. 8 S is generated.The variable setting time of the return time setting circuit 8 is set in increments in accordance with the cooling time of the load that has been overheated due to excessive fl-R.

The operation of m M Ha will be explained with reference to the time chart shown in FIG. In Figure 2, 1 cod is the motor current, and at each start of motor l, a starting current exceeding the rated current 1 flows, and normally the rated current gradually increases. lt IF
I settled on the following (but here I will explain the operation L motor L)
The figure shows the case where a transient p and a charging current l occur in an overload state.

After setting each time in the operating time setting circuit 5 and return time setting circuit 8 in advance, the motor 1 is turned on (No. 3 is added to the output memory circuit G of the cutoff circuit 6; +4 times is added, the cutoff circuit 6 turns on. Since the ζ cutoff section 3 is turned on, the current ■ flows and the motor controller starts. At this time, the motor turn-on No. 13 is applied to the return circuit 7, which starts the clock circuit lO (outputs the ε No. S). .Here, when the clock circuit lO is started for the first time by the start signal S, it issues a reset No. 13 S to reset the return number memory circuit 9, and the clock circuit 10 starts measuring time. ft Q or transient overload current■.

is flowing, so the A δ generation circuit 4 issues an overload signal S2 at time L2 after the elapse of the set time set by the operation time setting circuit 5, and as a result, the cutoff circuit 6 performs the cutoff operation and the cutoff section 3 is turned off. Cut off. At this time, the stop signal S from the cutoff circuit 6
5 is output to the timer 1to, and this stop signal S causes the timer circuit 10 to stop measuring time. At this time, the clock time Ta of the clock circuit 10, which corresponds to the closing time of the interrupter 30, is shorter than the predetermined time To, so the reset signal S is not generated. Since the state is the return number storage circuit 9, the return (11
The output signal S4 output to the circuit 7 is 1. It is. Therefore, the recovery circuit 7 is activated by the overload signal S□ from the signal generation circuit 4, and outputs a recovery signal s4 at time t after a relatively short recovery time Tr set by the recovery time setting circuit 8, and outputs the signal S4. Since the cutoff circuit 6 is restored via the circuit 6a and the cutoff section 3 is turned on again, the motor l is restarted. At this time, the return circuit 7 is set No. 13 S because the output signal S4 of the return number storage circuit 9 has been received.

is issued to set the return number memory circuit 9. clock circuit l
O restarts the time a1 with the same start signal S as the return No. 13 S from the return circuit 7. Kode motor l 7! !
<When an overload occurs and the circuit 4 issues an overload signal S2, the cutoff circuit G cuts off the cutoff section 3 at hour 11[4.Of course, the timekeeping circuit 10 stops timing. .

However, this time, since the return number memory circuit 9 is in the set state, the return circuit 7 passes the relatively long return time Tr set by the return time setting circuit 8, and the time t when the °C motor l has been sufficiently cooled. , and issues a return signal S4 to tltlt.
Re-energize section 3 and start circuit 10 when fit. In this way, the return count memory circuit 9 is not reset while the time measurement Ta of the clock circuit 10 does not exceed the predetermined time To, so even if the mltM section 3 is cut off, the cutoff section 3 is restarted in a relatively long return time Try. At time t, the interrupter 3 is turned on by the return signal S, and the clock circuit 1 is turned on.
If the motor 1 is operated below the rated current + r after 0 starts timing, the closing time of the cut-off section 3 is still 31 o'clock circuit l.
The measured time 'Ta of O continues for a long time and exceeds the predetermined time To. When the clock time Ta reaches the predetermined time To, the clock circuit 10
issues a reset signal S at time t7 to reset the return number storage circuit 9. In other words, the closing part 3 is turned on from □'1
m When the VL waiting time Ta) exceeds the predetermined time To, this relay performs the same operation as when the breaker 3 was first turned on, and then repeats the above operation depending on the load. It is possible to select the iTG input time by distinguishing whether the iTG has been turned on, re-loading after being cut off after a long input duration, or re-loading for the second time or later.

〔Effect of the invention〕

According to the present invention, it is possible to memorize whether or not the return circuit has performed a return operation after the interrupter is first turned on, and also to shut off the circuit. We have provided a return count memory circuit that is reset when the IF part continues to be turned on for longer than a predetermined time.・When the return circuit issues a return signal, this signal is "IT!" It is possible to determine whether it is the i1st time or the second or later time and select the °ζ return time.For example, the i! ! ! Temporary excess f+ that rarely continues
, due to M or malfunction;! ! When a disconnection occurs, the load operation rate can be improved by quickly restoring the system and restarting the operation. If true 73 negative what, the cut-off is re-blocked, this time with a relatively long return time i't? ;J is sufficiently cooled and operation continues. Note that the time to re-close the shut-off part is variable, so 11
(It can be adjusted to the thermal time constant of 1B, so it is effective because it does not waste unnecessary time when the IT input time is too early or too late).

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the automatic recovery (NI type adaptive 1'tn's) protective relay according to the present invention; FIG. 3 is a waveform diagram showing the operation of the 1'1 protection relay.

Claims (1)

[Claims] 1) A cutoff circuit that cuts off the cutoff section by an overload signal generated from a signal generation circuit in response to an overload current, and a return signal after a predetermined time set by a return time setting circuit after the overload signal is input. In the automatic reset type overload protective relay, the automatic reset type overload protection relay is equipped with a reset circuit that generates a signal to reset the cutoff circuit and re-close the cutoff section, wherein the reset time setting circuit is set to two stages, a fixed time and a variable time. , a return number storage circuit that stores whether the return signal is a first signal or a second or subsequent signal and supplies the return circuit with a signal for selecting a two-step set time set in the return time setting circuit; and a timing circuit that measures the duration of the closing of the cutoff section, and the recovery count storage circuit stores the stored state of the first signal when the load is first turned on and when the time measured by the timing circuit exceeds a predetermined time. An automatic reset type overload protection relay characterized in that the relay is configured to be set as follows.