JPH0633338U - Trigger breaker with priority - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent power failure of the entire load due to temporary concentration of load. The breaker is inserted into a circuit for supplying electric power to the loads L1 to L4 connected to the load connecting terminals t1 to t4, respectively, to limit the total load current to a limit value or less. Unit breakers B1 to B4 with an automatic tripping mechanism are provided, and the contacts S1 to S4 of these unit breakers are connected in series to the load connecting terminals t1 to t4, respectively. The terminals on the opposite side of the load connection terminals of the contacts S1 to S4 are commonly connected, and the trip coils TC1 to TC4 of the unit breakers B1 to B4 are connected in series between the common connection point and the power source P. Prioritize the unit breakers B1 to B4,
The sensitivities of the unit breakers B1 to B4 are set so that when the sum of the load currents exceeds the limit value, the contacts with higher priority will open before the contacts with lower priority.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a breaker (circuit breaker) that is inserted into a circuit that supplies power from a power source to a plurality of loads and limits the total load current to a limit value or less.

[0002]

[Prior art]

 As shown in FIG. 5, a conventional breaker B ′ of this type has one contact S and a trip coil TC, and when the predetermined current flows through the trip coil TC, the contact point S is removed. It is designed to open and the trip coil TC and the contact S are connected in series. The terminal of the trip coil TC on the side opposite to the contact S is connected to one end of the commercial power source P, and the loads L 1 to L 4 are connected in parallel between the terminal of the contact S on the side opposite to the coil TC and the other end of the power source P. Connected to. In this breaker, the trip coil TC trips the contact trip mechanism when the sum of the currents (total load current) flowing from the power source P to the loads L1 to L4 reaches the limit value (operating current value of the breaker). Then, the contact S is opened to stop energizing the loads L1 to L4.

[0003]

[Problems to be solved by the device]

 In recent years, the number of electric appliances has increased remarkably in offices and households, and if the maximum loads of electric appliances in use happen to overlap, the full load current may exceed the limit value.

For example, in FIG. 5, it is assumed that the load L1 is a computer, L2 is an air conditioner, L3 is an electronic range, and L4 is a dryer. In this case, for example, when the computer L1, the air conditioner L2, and the dryer L4 are being used, and the use of the microwave oven L3 is started when the temperature of the room rises and the load of the air conditioner rises, the full load current is reduced. May temporarily exceed the limit. In this case, if the power supply to the full load is stopped, the data being processed by the computer may be destroyed, which is not preferable.

In the case of using the conventional breaker shown in FIG. 5, if the total sum of the currents flowing through the loads L1 to L4 exceeds the limit value even temporarily, the energization of all the loads is stopped. As described above, if the load includes an important load that needs to avoid power outages as much as possible, there is a possibility that large damage may occur.

An object of the present invention is to provide a trip prioritized breaker capable of avoiding power failure of an important load as much as possible.

[0007]

[Means for Solving the Problems]

 The present invention is a breaker which is inserted into a circuit that supplies power to loads connected to n (n is an integer of 2 or more) load connection terminals and limits the total load current to a limit value or less. According to the present invention, n unit breakers with an automatic tripping mechanism are provided, each of which has a contact and a trip coil, and opens the contact when a predetermined current flows through the trip coil. The contacts of the n unit breakers are respectively connected in series to the n load connection terminals.

The contacts of the n unit breakers are connected in common to the respective terminals for load connection and the terminals on the opposite side, and the trip coils of the n unit breakers are connected between the common connection point and the power source. Connected in series or in parallel.

Priority is set for the n unit breakers, and when the sum of the load currents exceeds the limit value, the contact with the higher priority is opened before the contact with the lower priority. The unit breaker sensitivity is set.

In the present invention, it is not always necessary to prioritize all of the n unit breakers, and at least one unit breaker has a lower priority than other unit breakers. Then, prioritize.

For example, when four unit breakers B1 to B4 are provided, the unit breakers B1 to B2 to B3 to B4 may be arranged in the order of priority, but the unit breakers B1 to B3 are prioritized. The unit breakers B4 may have the same priority and only the unit breakers B1 to B3 may have a higher priority. Further, the unit breakers B 1 and B 2 may have the same priority, and the unit breakers B 2 and B 3 may have a higher priority than the unit breakers B 1 and B 2.

[0012]

[Action]

 In the above breaker, when the trip coils of the n unit breakers are connected in series, the sum of the currents flowing through the loaded loads flows through each trip coil. In this case, connect an appropriate sensitivity adjustment impedance in parallel to each trip coil, adjust the number of turns of each trip coil, and add an inertial delay mechanism to the trip mechanism of the contact of each unit breaker. The sensitivity of each unit breaker can be adjusted as appropriate by adjusting the delay time (response time) from when the energizing current of the trip coil reaches the limit value until the contact is tripped. it can.

When the trip coils of the n unit breakers are connected in parallel, the full load current is shunted to the trip coils of the n unit breakers. Also in this case, by adjusting the number of turns of the trip coil of each unit breaker, or by adjusting the response time by providing an inertial delay mechanism in the trip mechanism of the contact of each unit breaker, the response time of each unit breaker is adjusted. The sensitivity of can be adjusted.

In the present invention, the n unit breakers are prioritized so that when the full load current exceeds the limit value, the contact with the higher priority opens earlier than the contact with the lower priority. The sensitivity of n unit breakers is set. Therefore, when the full load current exceeds the limit value, only the contact of the unit breaker with the highest priority opens, and when the full load current falls below the limit value by opening this contact, energization to other loads continues. It Thus, according to the present invention, the contacts of all the unit breakers do not open at the same time when the full load current exceeds the limit value, and only the contacts of the unit breaker with the higher priority first open. Therefore, if a load connection terminal (for example, an outlet) for connecting a heavy load such as a computer that needs to avoid a power failure is connected to the contact of a unit breaker with a lower priority, the total load current will be temporary. The rise can prevent the important load from being cut off.

[0015]

【Example】

 FIG. 1 shows an embodiment of the present invention, in which P is a commercial power source, L1 to L4 are loads, and B is a breaker according to the present invention. In the present invention, a unit breaker is provided which has a contact for each load and a trip coil which opens the contact when a predetermined current flows. In this embodiment, the contact S1 and the trip coil TC1 form a first unit breaker B1, and the contact S2 and the trip coil TC2 form a second unit breaker B2. Similarly, the contact S3 and the trip coil TC3 form a third unit breaker B3, and the contact S4 and the trip coil TC4 form a fourth unit breaker B4.

The contacts S1 to S4 of the first to fourth unit breakers are respectively connected in series to the load connection terminals (outlets) t1 to t4, and the load connection terminals t1 to t4 are respectively loaded with loads L1 to L4. Are connected. The terminals on the opposite side of the load connection terminals of the contacts S1 to S4 are connected in common, and the contacts of the trip coils TC1 to TC4 of the four unit breakers are connected in series between the common connection point of the contacts S1 to S4 and the power source P. It is connected to the. Variable resistors VR1 to VR4 as impedances for sensitivity adjustment are connected in parallel to the trip coils TC1 to TC4, respectively. Priorities are set for the four unit breakers B1 to B4, and by adjusting the resistance values of the variable resistors VR1 to VR4, the total load current flowing from the power source P to the loads L1 to L4 is limited. The sensitivity of the unit breakers B1 to B4 is adjusted so that when the value is exceeded, the contact with higher priority opens earlier than the contact with lower priority.

Here, it is assumed that the unit breaker B4 has the highest priority, and that the priorities become lower in the order of B3, B2, and B1. In this case, when the total load current exceeds the operating current value I4, the contact S4 of the unit breaker B4 is opened first, and the total load current flowing when the contact S4 is open (the current flowing through the contacts S1 to S3 The contact point S3 of the unit breaker B3 should be opened when the sum total exceeds the operating current value I3 (> I4). Further, when the sum of the load currents (the sum of the currents flowing through the contacts S3 and S4) flowing when the contacts S3 and S4 are open exceeds the operating current value I2 (> I3), the contact S2 opens and the contacts S2 ... Adjust the sensitivity of the unit breakers B1 to B4 so that the contact S1 opens when the load current flowing through the contact S1 exceeds the operating current value I1 with S4 open. In order to adjust the sensitivity in this way, for example, the same unit breakers B1 to B4 are used so that the resistance values r1 to r4 of the variable resistors VR1 to VR4 have a relation of r1> r2> r3> r4. Set. In this case, the difference between the operating current values I1 to I4 is set as small as possible, and the maximum operating current value I1 is set equal to the limit value contracted with the electric power company.

In the above-mentioned embodiment, the important load that needs to avoid the power failure is connected to the contact of the unit breaker having the low priority. For example, when a computer, an air conditioner, a microwave oven, and a dryer are the loads, the computer is the most important load, and then the air conditioner, the microwave oven, and the dryer become less important in that order. And In this case, load L1 is a computer, L2 is an air conditioner, L3 is a microwave oven, and L4 is a dryer. Here, when the microwave oven L3 is started to be used while the temperature of the room rises and the load of the air conditioner increases while the computer L1, the air conditioner L2, and the dryer L4 are in use, the full load current is If the contractual limit value I1 is exceeded, the contact S4 of the unit breaker with the highest priority opens when the total load current reaches the operating current value I4 (<I1). As a result, the full load current becomes equal to or less than the limit value, so that energization to the other loads L1 to L3 is continued. Therefore, energization to other loads including the computer L1 which is an important load is continued.

In the above example, the unit breakers B1 to B4 have different sensitivities by different operating current values for operating the unit breakers. However, the inertia of the contact trip mechanism of the unit breakers B1 to B4 is different. By providing a delay mechanism, the delay time required for the contacts to actually open after the currents flowing through the trip coils of the unit breakers B1 to B4 have reached their operating current values and the trip mechanism has tripped (unit breaker The unit breakers B1 to B4 may have different sensitivities by changing the response times of the unit breakers. In this case, the variable resistors VR1 to VR4 as impedances for sensitivity adjustment are unnecessary, and the current values (load current limit values) that need to flow through the trip coils TC1 to TC4 of the unit breakers B1 to B4 are equal. Just keep it.

In the above example, the case where four load connection terminals are provided is taken as an example, but the present proposal can be generally applied to the case where n load connection terminals are provided.

In the above embodiment, the tripping coils TC1, TC2, ... Of n unit breakers are connected in series between the common connection point of the contacts and the power source, but as shown in FIG. The removal coils TC1, TC2, ... May be connected in parallel between the common connection point of the contacts and the power source P.

As shown in FIG. 3, the contacts of the branch circuit breakers NFB1 to NFB5 are connected in series to the load connection terminals t1 to t5, respectively, and the common connection point of these contacts and the power source are connected. It is also conceivable to connect the contacts of the main circuit breaker NFBo between them.

However, in the case of such a configuration, there arise inconveniences that the capacities of all the circuits cannot be effectively used and that all the loads are out of power when the total load current exceeds the limit value.

For example, as shown in FIG. 3, when the operating current value of the main circuit breaker is 10 A and the operating current values of the branch circuit breakers NFB1 to NFB5 are 2A, 2A, 2A, 3A and 1A, respectively. When trying to use only the branch circuit of NFB5, only a maximum of 1A can be used, and the current capacity of 10A of the entire circuit cannot be effectively used. On the other hand, with the configuration of the present invention, the current capacity of the entire circuit can be utilized even when only one load connecting terminal is used.

As shown in FIG. 4, when the operating current value of the branch circuit breakers NFB1 to NFB5 is set to 5 A, the total load current exceeds the limit value 10 A when the load peaks overlap. There is a risk that the main circuit breaker NFBo will operate and the entire load will be cut off. In the present invention, in such a case, only the contact point of the unit breaker having a high priority is opened, so that it is possible to prevent the power failure of the entire load.

[0026]

[Effect of device]

 As described above, according to the present invention, the priority is given to the n unit breakers, and when the full load current exceeds the limit value, the contact with the higher priority opens before the contact with the lower priority. Since the sensitivity of n unit breakers is set as above, when the full load current exceeds the limit value, only the contact of the unit breaker with the highest priority is opened and the contacts of other unit breakers remain closed. can do.

Therefore, according to the present invention, by connecting a load connection terminal for connecting an important load such as a computer that needs to avoid power failure to a contact of a unit breaker having a low priority, There is an advantage that it is possible to prevent power failure of important loads due to a temporary increase in load current.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of a conventional breaker.

FIG. 4 is a circuit diagram showing an example in which the operating current value is set differently in the breaker of FIG.

FIG. 5 is a circuit diagram of a power distribution circuit using another conventional breaker.

[Explanation of symbols]

 P Commercial power supply B Breaker B1 to B4 Unit breaker TC1 to TC4 Tripping coil S1 to S4 Contact points t1 to t4 Load connection terminals L1 to L4 Load

Claims (1)

[Scope of utility model registration request] 1. A breaker which is inserted into a circuit for supplying power to loads respectively connected to n (n is an integer of 2 or more) load connecting terminals and limits the total sum of load currents to a limit value or less. Then, n unit breakers with an automatic tripping mechanism are provided, each of which has a contact point and a tripping coil and opens the contact point when a predetermined current flows through the tripping coil. The contacts are connected in series to the n load connection terminals, and the n unit breaker contacts are connected in common to their respective load connection terminals and terminals on the opposite side, and their common connection points. When the trip coils of the n unit breakers are connected in series or in parallel with the power source, and the priority order is set for the n unit breakers, and the total load current exceeds the limit value. Contacts with high priority A trip-priority breaker characterized in that the sensitivities of the n unit breakers are set so that they are opened prior to a contact having a lower priority.