Electricity safety overload power-off control device for college student dormitory

Abstract

The utility model provides a college student dormitory power utilization safety overload power -off control device, including control box, its inside is equipped with wiring terminal row, sliding type zero line busbar, power utilization safety overload protector and safety circuit breaker controller, control box side is equipped with cable inlet and outlet wire hole and ventilation grid hole, and low -power consumption components such as LED safety indicating lamp power supply, front side is equipped with the safety box cover of safety lock, this device can real -time monitoring load state, the utility model proposes when overloading through thermal expansion medium phase change drive linkage frame body displacement, cooperate joule heat -sensitive petal's current heating signal, synchronous trigger pressure -sensitive push rod pops out, hysteresis damping claw locking loop, finally through the high -frequency contraction of resonance tripping ring realizes millisecond level power -off. The mechanism has realized overload early warning, quick tripping and remote feedback integrated operation, can accurate and precise avoid impact current false triggering, adapts complex power utilization scene in dormitory, provides reliable guarantee for college dormitory power utilization safety.

Description

Technical Field

[0001] This utility model relates to the field of electrical control boxes, and more specifically, to an overload power-off control device for electrical safety in university student dormitories. Background Technology

[0002] With the continuous expansion of university scale and the sustained growth of student numbers, the electricity load in student dormitories is increasing daily. To meet daily needs, students commonly use desk lamps, computers, mobile phone chargers, electric fans, and even prohibited high-power appliances such as electric kettles, rice cookers, and electric heaters, causing dormitory power lines to operate under high load or even overload conditions for extended periods. Traditional dormitory power distribution systems often use simple air switches or ordinary circuit breakers for protection, lacking targeted safety monitoring and intelligent management methods.

[0003] Patent application CN202021502429.8 discloses a power control box device, belonging to the technical field of control box equipment. It includes a box body, a door, and a mounting frame. The door is hinged to the surface of the box body. The mounting frame is located inside the box cavity. Air inlets are embedded in the top of both side walls of the box body. A support frame is installed in the center of the top of the box cavity. A fan is installed on the bottom surface of the support frame. A partition plate is installed on one side of the bottom of the support frame. An exhaust pipe is embedded in the bottom surface of the box body. Fixed frames are installed on both sides of the top surface of the box cavity. PTC heating elements are installed inside the fixed frames, specifically in three groups. This invention, through the cooperation of a temperature monitor and a microcontroller, can flexibly monitor the temperature inside the box and control the operation of the fan and PTC heating elements, thus achieving both heat dissipation and insulation, preventing condensation inside the box.

[0004] Currently, the electrical control devices commonly used in university student dormitories have the following shortcomings: Students frequently plug and unplug power strips, leading to serious problems such as socket overload, poor contact, or aging wiring. This poses a risk of unsafe electricity use.

[0005] Traditional distribution boxes typically have fixed-installation terminals and busbars for internal components, making it impossible to adjust their layout according to different circuit connections. Furthermore, the wiring is often messy, lacking a dedicated cable management structure, requiring complete disassembly for maintenance, which is cumbersome and prone to secondary faults. Additionally, the boxes are usually unlocked or use only simple padlocks, allowing students to easily open them and tamper with the wiring, posing serious safety hazards. While existing power control boxes incorporate current monitoring and remote control functions, their mechanical tripping mechanisms still suffer from structural complexity, insufficient reliability, and delayed thermal response. Especially in high-density power environments, failure to quickly and reliably cut off power at the initial stage of overload poses a significant threat to student safety and campus property. Therefore, this paper proposes an overload power-off control device for electrical safety in university student dormitories. Utility Model Content

[0006] The purpose of this utility model is to address the problems raised in the existing background technology. To achieve the above-mentioned purpose, this utility model provides the following technical solution: an overload power-off control device for electrical safety in university student dormitories, including a control box. A safety cover is provided on the front side of the control box. A ventilation grille is provided on the upper side of the control box. A terminal block is provided inside the control box. A sliding neutral busbar is provided below the terminal block. The terminal block is connected to an overload protection device. A wire harness management and connection slot is provided below the sliding neutral busbar. An overload power-off linkage mechanism is provided inside the control box.

[0007] As a preferred technical solution of this utility model, the overload power-off linkage mechanism is provided with a thermally expanding rotating contact rod, which is connected to the contact rod linkage frame. The upper two sides of the contact rod linkage frame are provided with linkage armature rails. The contact rod linkage frame is provided with a pressure-sensitive push rod, which is provided with a push rod top block. The pressure-sensitive push rod is located in a magnetic suction sliding groove. The end of the pressure-sensitive push rod is provided with a hysteresis damping claw. The upper side of the hysteresis damping claw is provided with a Joule thermistor, which is connected to a resonant trip ring.

[0008] As a preferred technical solution of this utility model, the control box is provided with a cable inlet hole and a cable outlet hole on its side.

[0009] As a preferred technical solution of this utility model, the safety box cover is connected to the control box body via a cover hinge, and the safety box cover is equipped with a cover electrical safety lock.

[0010] As a preferred technical solution of this utility model, the terminal block is slidably mounted on the terminal sliding guide rail.

[0011] As a preferred technical solution of this utility model, the sliding neutral busbar is slidably mounted on the neutral busbar sliding guide rail.

[0012] As a preferred technical solution of this utility model, a safety circuit breaker controller is provided on the side of the electrical safety overload protector.

[0013] As a preferred embodiment of this invention, the safety circuit breaker controller is slidably mounted on the safety circuit breaker mounting rail.

[0014] As a preferred technical solution of this utility model, an adjustable plug seat is provided on the side of the sliding neutral busbar, and the adjustable plug seat is slidably mounted on the plug seat slide rail.

[0015] As a preferred technical solution of this utility model, the safety box cover is provided with an LED safety indicator light.

[0016] As a preferred technical solution of this utility model, an energy-saving solar panel is provided on the top of the control box.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model device integrates an electrical safety overload protector and a safety circuit breaker, which can automatically cut off the power supply in milliseconds when overload, short circuit or abnormal power use occurs, effectively preventing electrical fires and electric shock accidents; together with the closed safety box cover with a safety lock, it can prevent students from privately connecting or operating the internal circuit without authorization, thus eliminating safety hazards from the source.

[0018] The terminal block, sliding neutral busbar, adjustable plug socket and safety circuit breaker of this utility model all adopt a sliding guide rail structure, which can flexibly adjust the position according to the actual wiring needs. This not only simplifies the initial installation process, but also greatly improves the convenience of later maintenance and replacement of parts, and reduces operation and maintenance costs.

[0019] This utility model guides students to use compliant sockets by centrally setting standardized adjustable plug sockets and wire harness management connection slots, avoiding the use of high-power appliances or unauthorized power strips, thereby achieving effective control over student dormitory electricity use and improving the standardization of campus electricity management.

[0020] The control box of this utility model has ventilation grilles on the upper side, which ensures good heat dissipation while preventing foreign objects or liquids from directly entering the box; the overall enclosed structure combined with the safety lock design has dustproof, moisture-proof and accidental touch prevention functions, and is suitable for the complex use environment of dormitories.

[0021] This utility model device integrates an energy-saving solar panel on the top, which can convert solar energy into electrical energy to power the LED safety indicator and low-power monitoring module, reducing public electricity consumption. The LED safety indicator displays the device's operating status in real time, allowing managers to quickly determine the equipment's condition without opening the box, improving inspection efficiency and realizing intelligent and visual power management.

[0022] This utility model features a hysteresis damping claw that works in conjunction with a resonant trip ring to provide stable damping to prevent maloperation during normal operation and to quickly release the pressure-sensitive push rod during overload. Combined with the resonant amplification effect, it significantly shortens the trip response time and improves protection sensitivity.

[0023] The contact rod linkage frame, linkage rail, and push rod top block form an integrated transmission chain, which is compact in structure and highly efficient in transmission. It avoids the risk of electronic component failure in high-voltage environments and is suitable for dormitory scenarios where there is no one on duty for a long time. This utility model can automatically complete mechanical power-off without relying on external control signals, fundamentally cutting off the source of danger and preventing safety hazards caused by human intervention delays or system communication failures. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of the present invention;

[0025] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0026] Figure 3 A schematic diagram of the sliding neutral busbar structure provided by this utility model;

[0027] Figure 4 A partial schematic diagram of the zero-line busbar sliding guide rail provided by this utility model;

[0028] Figure 5 A partial schematic diagram of the installation track for the safety circuit breaker provided by this utility model;

[0029] Figure 6 This is a partial schematic diagram of the adjustable plug socket provided by this utility model;

[0030] Figure 7 A schematic diagram of the overload power-off linkage mechanism provided by this utility model;

[0031] Figure 8 A partial three-dimensional schematic diagram of the overload power-off linkage mechanism provided by this utility model;

[0032] Figure 9 This is a partial schematic diagram of the linkage rail provided by this utility model.

[0033] The image shows:

[0034] 1. Control box; 101. Cable inlet; 102. Cable outlet; 2. Safety box cover; 201. Cover hinge; 202. Cover electrical safety lock;

[0035] 3. Ventilation grille holes; 4. Terminal block; 401. Terminal block sliding rail; 5. Sliding neutral busbar; 501. Neutral busbar sliding rail;

[0036] 6. Electrical safety overload protector; 7. Wiring harness connection slots; 8. Safety circuit breaker;

[0037] 9. Safety circuit breaker mounting rail; 10. Adjustable plug socket; 1001. Plug socket slide rail; 11. LED safety indicator light; 12. Energy-saving solar panel.

[0038] 13. Overload power failure linkage mechanism; 1301. Thermal expansion rotating contact rod; 13011. Contact rod linkage frame; 1302. Linkage armature rail; 1303. Pressure-sensitive push rod; 1304. Push rod top block; 1305. Magnetic suction sliding groove; 1306. Magnetic hysteresis damping claw; 1307. Resonant trip ring; 1308. Joule thermistor. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model.

[0040] Therefore, the following detailed description of the embodiments of this utility model is not intended to limit the scope of the claimed utility model, but merely illustrates some embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model. It should be noted that, in the absence of conflict, the embodiments and features and technical solutions in the embodiments of this utility model can be combined with each other. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0041] Example 1: A power overload protection device for electrical safety in university student dormitories includes a control box 1, a safety cover 2 on the front of the control box 1, a ventilation grille 3 on the upper side of the control box 1, a terminal block 4 inside the control box 1, a sliding neutral busbar 5 below the terminal block 4, the terminal block 4 being connected to an electrical overload protector 6, and a wire harness management connection slot 7 below the sliding neutral busbar 5. The control box 1 is equipped with an overload power-off linkage mechanism 13. The overload power-off linkage mechanism 13 is equipped with a thermally expanding rotating contact rod 1301, which is connected to the contact rod linkage frame 13011. The upper two sides of the contact rod linkage frame 13011 are equipped with linkage armature rails 1302. The contact rod linkage frame 13011 is equipped with a pressure-sensitive push rod 1303, which is equipped with a push rod top block 1304. The pressure-sensitive push rod 1303 is located in a magnetic suction sliding groove 1305. The end of the pressure-sensitive push rod 1303 is equipped with a hysteresis damping claw 1306. The upper side of the hysteresis damping claw 1306 is equipped with a Joule thermistor 1308, which is connected to a resonant trip ring 1307. The side of the control box 1 is equipped with a cable inlet hole 101 and a cable outlet hole 102. The safety box cover 2 is connected to the control box 1 via a cover hinge 201, and a cover electrical safety lock 202 is provided on the safety box cover 2. The terminal block 4 is slidably mounted on the terminal block sliding rail 401. The sliding neutral busbar 5 is slidably mounted on the neutral busbar sliding rail 501. A safety circuit breaker 8 is provided on the side of the electrical safety overload protector 6.

[0042] The safety circuit breaker controller 8 is slidably mounted on the safety circuit breaker mounting rail 9. An adjustable plug socket 10 is located on the side of the sliding neutral busbar 5, and the adjustable plug socket 10 is slidably mounted on the plug socket slide rail 1001. An LED safety indicator light 11 is installed on the safety box cover 2. An energy-saving solar panel 12 is installed on the top of the control box 1.

[0043] Working principle of the overload power-off control device for electrical safety in university student dormitories: The external power cable enters the device through the cable inlet 101 on the side of the control box 1, and is connected and distributed to the main circuit via the terminal block 4. The terminal block 4 can be flexibly adjusted along the terminal sliding rail 401 to facilitate the connection and maintenance of cables of different specifications. The current is then transmitted to the overload protection device 6, which monitors the circuit current in real time.

[0044] When the electrical load exceeds the set threshold or a short circuit fault is detected, the electrical safety overload protector 6 immediately triggers and activates the safety circuit breaker 8. The safety circuit breaker 8 is installed on the safety circuit breaker mounting rail 9 and can slide along the rail to adjust its position for easy maintenance and replacement. Once triggered, the safety circuit breaker 8 quickly cuts off the power supply circuit to prevent electrical fires or equipment damage, ensuring the safety of students and their property.

[0045] When the current in the dormitory's electrical circuit increases abnormally, or when an overload or short circuit occurs, the current flowing through the overload trip linkage mechanism 13 increases accordingly. At this time, the Joule thermistor 1308 rapidly generates Joule heat due to the large current flowing through it, and its temperature rises sharply. Because the Joule thermistor 1308 is made of a thermistor material, it undergoes significant thermal expansion after being heated, which causes the resonant trip ring 1307, which is rigidly connected to it, to deform or displace.

[0046] The deformation of the resonant release ring 1307 triggers the action of the hysteresis damping claw 1306, causing it to release from the constraint state on the pressure-sensitive push rod 1303. Under the action of the internal preset elastic force or electromagnetic force, the pressure-sensitive push rod 1303 slides rapidly along the magnetic sliding groove 1305, pushing the push rod top block 1304 to move upward. The displacement of the push rod top block 1304 further drives the entire contact rod linkage frame 13011 to rotate or translate.

[0047] The movement of the linkage frame 13011 drives the thermally expanding rotating contact rod 1301 connected to it to move synchronously. At the same time, the linkage rails 1302 on both sides of its upper part mechanically link with the external electromagnetic tripping device or the main control relay, forcibly cutting off the power supply circuit. During this process, the thermally expanding rotating contact rod 1301 can also assist in accelerating the power-off action due to its own thermal expansion, forming a dual thermo-mechanical response mechanism to improve the power-off response speed and reliability.

[0048] The entire overload power-off linkage mechanism 13 achieves rapid identification of overload current and automatic power-off protection through the thermal sensing of the Joule thermistor 1308, the damping release of the hysteresis damping claw 1306, the mechanical transmission of the pressure-sensitive push rod 1303, and the linkage execution of the thermal expansion rotating contact rod 1301. This effectively prevents safety accidents such as fires caused by overheating of the circuit and ensures the safe and energy-saving operation of electricity in student dormitories.

[0049] The sliding neutral busbar 5 achieves horizontal displacement adjustment via the neutral busbar sliding rail 501, adapting to different wiring layouts and ensuring centralized and reliable connection of the neutral wire. Its side-mounted adjustable plug socket 10 can slide and position itself on the plug socket slide rail 1001, supporting flexible access for various electrical equipment plugs, meeting diverse power needs in dormitories, and preventing unauthorized wiring.

[0050] The device has internal cable management slots 7 for neatly organizing incoming and outgoing cables, improving wiring cleanliness and maintenance efficiency. Ventilation grilles 3 are located on the upper side of the control box 1, creating a natural convection channel to effectively dissipate heat generated by internal components, preventing excessive temperature rise that could affect equipment lifespan and safety.

[0051] The control box 1 is equipped with a safety cover 2 on the front, featuring a cover hinge 201 and a cover electrical safety lock 202. Only authorized personnel can open it to prevent students from operating the internal electrical components without authorization. The surface of the safety cover 2 integrates LED safety indicator lights 11, which display the real-time operating status of the device, such as normal power supply, overload alarm, and power failure protection, facilitating managers to quickly identify abnormal situations.

[0052] An energy-saving solar panel 12 is installed on the top of the control box 1. Under daylight conditions, it converts solar energy into electrical energy to provide auxiliary power for LED indicator lights 11, control circuits or low-power monitoring modules, reducing dependence on mains power and practicing the concept of energy conservation and emission reduction on campus.

[0053] The working process of the overload power-off control device for electrical safety in university student dormitories: The external power supply cable enters the device through the cable inlet 101 on the side of the control box 1 and connects to the adjustable terminal block 4. The terminal block 4 is flexibly positioned along the terminal sliding guide 401, allowing for easy adjustment according to actual wiring requirements. After the main circuit connection is completed, the current is transmitted to the overload protection device 6 via the terminal block 4.

[0054] Under normal circumstances, the electrical safety overload protector 6 remains closed, and the current continues to flow to the sliding neutral busbar 5 and downstream electrical circuits. Various electrical devices in the dormitory are connected to the system via adjustable plug sockets 10. These sockets can slide and adjust on the plug socket slide rail 1001 to accommodate plugs of different positions and types, ensuring safe and standardized electrical connections. Simultaneously, the cable management connection slot holes 7 neatly secure incoming and outgoing cables, ensuring clean and reliable internal wiring.

[0055] During operation, the electrical safety overload protector 6 continuously monitors the circuit current. An LED safety indicator 11 is mounted on the surface of the safety box cover 2; a solid green light indicates normal power supply. If an overload or potential malfunction occurs, the indicator light turns red or flashes, prompting management personnel to intervene promptly. The entire control box 1 is sealed by a safety box cover 2 with an electrical safety lock 202, preventing students from unauthorized opening and operation, thus ensuring electrical safety.

[0056] When the dormitory's electrical load exceeds the set safety threshold, or when an abnormal situation such as a short circuit or leakage occurs, the electrical safety overload protector 6 immediately activates and triggers the safety circuit breaker 8 linked to it. The safety circuit breaker 8 quickly cuts off the main power supply circuit along the safety circuit breaker mounting rail 9, achieving millisecond-level power outage protection and effectively preventing electrical fires or equipment damage.

[0057] When the dormitory's electrical load is within the rated range, the current flowing through the overload disconnect linkage mechanism 13 is stable, the Joule thermistor 1308 has a low temperature, and no significant thermal expansion occurs. At this time, the hysteresis damping claw 1306 maintains effective constraint on the pressure-sensitive push rod 1303 within the magnetic sliding groove 1305. The pressure-sensitive push rod 1303 is in its initial position, the push rod top block 1304 does not move, the contact rod linkage frame 13011 and the thermally expanding rotating contact rod 1301 remain in a closed state, and the power supply circuit is normally connected.

[0058] When abnormal situations such as the use of high-power unauthorized electrical appliances, aging wiring, or short circuits occur in the dormitory, the circuit current increases rapidly, exceeding the set threshold. The large current flows through the Joule thermistor 1308, causing it to heat up rapidly due to the Joule effect and undergo significant thermal expansion.

[0059] The thermal expansion of the Joule thermistor 1308 causes deformation or displacement of the resonant trip ring 1307 connected to it, which releases the limiting effect on the hysteresis damping claw 1306. The hysteresis damping claw 1306 then releases and loses its damping constraint within the magnetic sliding groove 1305.

[0060] The pressure-sensitive push rod 1303 slides rapidly along the magnetic sliding groove 1305 under the action of the internal preset spring force or electromagnetic driving force, pushing the push rod top block 1304 at its top to move upward.

[0061] The upward force of the push rod top block 1304 is transmitted to the contact rod linkage frame 13011, causing it to rotate or translate. At the same time, the linkage rails 1302 on both sides of the upper part of the contact rod linkage frame 13011 move synchronously, mechanically linking with the tripping mechanism of the external main control relay or circuit breaker.

[0062] During the process of continuous excessive current, the thermal expansion rotating contact rod 1301 itself also undergoes thermal expansion due to temperature rise, further accelerating the change of its rotation angle, strengthening the disconnection action, and forming a thermo-mechanical dual response mechanism.

[0063] The above-mentioned linkage ultimately causes the thermally expanded rotating contact rod 1301 to disengage from the contact position, cutting off the main power supply circuit and realizing automatic, fast, and reliable overload power-off protection, effectively preventing safety accidents such as line overheating, equipment damage, or electrical fires.

[0064] After the fault is cleared and the system has cooled down, it is necessary to manually or remotely reset the pressure-sensitive push rod 1303 to return to its original position, relock the hysteresis damping claw 1306, and restore the contact rod linkage frame 13011 and the thermally expanded rotating contact rod 1301 to the closed state before the system can be powered back.

[0065] The heat generated during the operation of the device is naturally discharged through the ventilation grille holes 3 on the upper side of the control box 1, forming air convection, maintaining the internal components within a safe temperature range, and improving the stability and reliability of the system in long-term operation.

[0066] Under daylight conditions, the energy-saving solar panel 12 installed on the top of the control box 1 converts light energy into electrical energy, providing auxiliary power for the LED safety indicator 11, monitoring module or low-power control unit, reducing mains power consumption and achieving green and energy-saving operation.

[0067] The above embodiments are only used to illustrate the present utility model and are not intended to limit the technical solutions described in the present utility model. Although the present utility model has been described in detail with reference to the above embodiments, the present utility model is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present utility model, and all technical solutions and improvements that do not depart from the spirit and scope of the utility model, are covered within the scope of the claims of the present utility model.

Claims

1. A power overload protection device for electricity use in university student dormitories, comprising a control box (1), characterized in that, The control box (1) is provided with a safety cover (2) on the front side, and a ventilation grid hole (3) is provided on the upper side of the control box (1). A terminal block (4) is provided inside the control box (1). A sliding neutral busbar (5) is provided below the terminal block (4). The terminal block (4) is connected to an electrical safety overload protector (6). A wire harness organizing connection slot hole (7) is provided below the sliding neutral busbar (5). An overload power-off linkage mechanism (13) is provided inside the control box (1).

2. The overload power-off control device for electrical safety in university student dormitories according to claim 1, characterized in that, The overload power-off linkage mechanism (13) is provided with a thermally expanding rotating contact rod (1301), which is connected to the contact rod linkage frame (13011). The upper two sides of the contact rod linkage frame (13011) are provided with linkage armature rails (1302). The contact rod linkage frame (13011) is provided with a pressure-sensitive push rod (1303), which is provided with a push rod top block (1304). The pressure-sensitive push rod (1303) is located in the magnetic suction sliding groove (1305). The end of the pressure-sensitive push rod (1303) is provided with a hysteresis damping claw (1306). The upper side of the hysteresis damping claw (1306) is provided with a Joule thermistor (1308), which is connected to the resonant trip ring (1307).

3. The overload power-off control device for electrical safety in university student dormitories according to claim 2, characterized in that, The control box (1) is provided with a cable inlet hole (101) and a cable outlet hole (102) on its side. The safety box cover (2) is connected to the control box (1) through a box cover hinge (201). The safety box cover (2) is provided with a box cover electrical safety lock (202).

4. The overload power-off control device for electrical safety in university student dormitories according to claim 3, characterized in that, The terminal block (4) is slidably mounted on the terminal sliding guide rail (401).

5. The overload power-off control device for electrical safety in university student dormitories according to claim 4, characterized in that, The sliding neutral busbar (5) is slidably mounted on the neutral busbar sliding guide rail (501).

6. The overload power-off control device for electrical safety in university student dormitories according to claim 5, characterized in that, The electrical safety overload protector (6) is equipped with a safety circuit breaker (8) on its side.

7. The overload power-off control device for electrical safety in university student dormitories according to claim 6, characterized in that, The safety circuit breaker controller (8) is slidably mounted on the safety circuit breaker mounting rail (9).

8. The overload power-off control device for electrical safety in university student dormitories according to claim 7, characterized in that, The sliding neutral busbar (5) is provided with an adjustable plug socket (10) on its side, and the adjustable plug socket (10) is slidably mounted on the plug socket slide rail (1001).

9. The overload power-off control device for electrical safety in university student dormitories according to claim 8, characterized in that, An LED safety indicator light (11) is provided on the safety box cover (2).

10. The overload power-off control device for electrical safety in university student dormitories according to claim 9, characterized in that, An energy-saving solar panel (12) is installed on the top of the control box (1).

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