Aircraft gas path accessory performance test power-on and power-off control system

Abstract

The utility model relates to a power-on and power-off control system for an aircraft gas path accessory performance test, which belongs to the technical field of gas path accessory performance testing and comprises an electromagnetic relay, a wireless remote control switch and a first power supply. One contact in a group of contacts of the electromagnetic relay is used for connecting a test power supply, and the other contact is used for connecting a tested accessory to form a first series loop; a coil of the electromagnetic relay is connected with the first power source through the wireless remote control switch to form a second series loop, and the wireless remote control switch is used for receiving the power-on control instruction to be switched on or receiving the power-off control instruction to be switched off. According to the utility model, a power-on control instruction or a power-off control instruction is remotely emitted, and the wireless remote control switch controls the suction or disconnection of the electromagnetic relay contact, so that the power-on and power-off control of the test power supply and the tested accessory is realized, a tester does not directly contact the test any more, and the test process can be indirectly controlled at a distance or outside a test room; and the test safety is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of gas path accessory performance testing technology, and in particular to an on / off control system for aircraft gas path accessory performance testing. Background Technology

[0002] There are many accessories in the air control system of an aircraft. The air control system is mostly divided into cold and hot circuits. The temperature and pressure in the cockpit or passenger / cargo compartment are adjusted by the ratio of cold and hot air flow to ensure the internal temperature and air pressure and maintain comfort. The performance test of the air circuit accessories after repair can only be achieved by simulating the working environment on the aircraft to obtain more accurate test results and verify the performance of the accessories.

[0003] In existing technology, for example, a certain type of high-temperature and high-pressure valve has an operating pressure of over 2 MPa, a temperature of over 200°C, and a flow rate of over 2000 kg / h. When testing it, the wiring of the power-on / off control system is as follows: Figure 1 As shown, the operation is as follows Figure 2 As shown, during the test, the tester and the accessory under test are in the same room. The tester needs to constantly turn the experimental switch on and off to control the power supply to the test circuit.

[0004] The testing personnel and the tested accessories are in the same room. Due to the harsh high-temperature and high-pressure testing environment, the high-pressure and high-flow-rate gas can cause a gas hammer effect when personnel open and close the high-temperature and high-pressure test, and the risk of the test pipeline detaching, there are significant safety hazards. Utility Model Content

[0005] In view of this, it is necessary to provide a power-on / off control system for testing the performance of aircraft gas path accessories, in order to solve the problem of significant safety hazards caused by test personnel and the accessories being tested being in the same room in the existing technology.

[0006] To address the aforementioned issues, this invention provides a power-on / off control system for testing the performance of aircraft gas path accessories, comprising an electromagnetic relay, a wireless remote control switch, and a first power supply.

[0007] One of the contacts of the electromagnetic relay is used to connect to the test power supply, and the other contact is used to connect to the accessory under test, forming a first series circuit;

[0008] The coil of the electromagnetic relay is connected to the first power source through the wireless remote control switch to form a second series circuit. The wireless remote control switch is used to receive a power-on control command to close or a power-off control command to open.

[0009] In some possible implementations, the electromagnetic relay is a normally open electromagnetic relay.

[0010] In some possible implementations, a freewheeling diode is connected in parallel across the coil of the electromagnetic relay. The positive terminal of the freewheeling diode is connected to the negative terminal of the electromagnetic relay coil, and the negative terminal of the freewheeling diode is connected to the positive terminal of the electromagnetic relay coil.

[0011] In some possible implementations, a fuse is also connected to the first series circuit.

[0012] In some possible implementations, the first power supply is a voltage regulation control module, the input terminal of which is connected to the output terminal of the test power supply, and the voltage regulation control module is used to convert the voltage input to the test power supply into a first preset voltage for output.

[0013] In some possible implementations, the voltage regulation control module employs a DC-DC converter;

[0014] In some possible implementations, the wireless remote control switch includes a transmitter and a receiver, the receiver including a first chip, a second chip, and a switching transistor;

[0015] The transmitter is used to transmit power-on control commands or power-off control commands;

[0016] The first power supply is connected to the power input terminals of the first chip and the second chip;

[0017] The control output terminal of the first chip is connected to the control input terminal of the second chip, and is used to receive power-on control commands or power-off control commands transmitted in the form of radio waves, and convert the power-on control commands or power-off control commands transmitted in the form of radio waves into power-on control commands or power-off control commands transmitted in the form of electrical signals and transmit them to the second chip.

[0018] The control output terminal of the second chip is connected to the control terminal of the switching transistor, and is used to receive the power-on control command transmitted in the form of an electrical signal and output a second preset voltage to the control terminal of the switching transistor, or to receive the power-off control command transmitted in the form of an electrical signal and output a third preset voltage to the control terminal of the switching transistor, wherein the third preset voltage is less than the second preset voltage.

[0019] The input and output terminals of the switching transistor are connected to the first power supply through the coil of the electromagnetic relay to form the second series circuit. When the control terminal voltage of the switching transistor reaches the second preset voltage, the channel inside the switching transistor is turned on.

[0020] In some possible implementations, the transmitter includes a second power supply, a first switch, a third chip, and a fourth chip;

[0021] The second power supply is connected to the power input terminals of the third chip and the fourth chip via the first switch;

[0022] The control output terminal of the third chip is connected to the control input terminal of the fourth chip, and is used to output a power-on control command or a power-off control command transmitted in the form of an electrical signal to the fourth chip.

[0023] The fourth chip is used to amplify the power-on control command or power-off control command transmitted in the form of an electrical signal, and convert the amplified power-on control command or power-off control command transmitted in the form of an electrical signal into a power-on control command or power-off control command transmitted in the form of radio waves for transmission.

[0024] In some possible implementations, the first power supply is connected to a changeover switch, the moving contact of which switches between a first stationary contact and a second stationary contact. The first stationary contact is connected to the coil of the electromagnetic relay via a long-line switch. The first power supply, the long-line switch, and the coil of the electromagnetic relay form a third series circuit through the first stationary contact. The second stationary contact is connected to the coil of the electromagnetic relay via a wireless remote control switch. The first power supply, the wireless remote control switch, and the coil of the electromagnetic relay form a second series circuit through the second stationary contact.

[0025] In some possible implementations, the changeover switch is a two-pin changeover switch.

[0026] The beneficial effects of this utility model are as follows: The power-on / off control system for aircraft gas path accessory performance testing provided by this utility model allows for the following: When the accessory under test needs to be powered on, a power-on control command is remotely transmitted. The wireless remote control switch receives the power-on control command and closes, the second series circuit is turned on, the first power supply powers the coil of the electromagnetic relay, the contacts of the electromagnetic relay close, the first series circuit is turned on, and the accessory under test is powered on, thus completing the power-on control. When the accessory under test needs to be de-powered, a power-off control command is remotely transmitted. The wireless remote control switch receives the power-off control command and disconnects, the second series circuit is disconnected, the first power supply stops powering the coil of the electromagnetic relay, the contacts of the electromagnetic relay open, the first series circuit is disconnected, and the accessory under test is de-powered, thus completing the power-off control. In this way, the tester no longer needs to directly contact the test and can indirectly control the test process from a distance or outside the test room, greatly improving the safety of the test. Furthermore, directly lengthening the test control line in the existing technology will affect the test parameters. As long as it is a wire, it will have resistance and produce a voltage division effect. According to Ohm's law, when the current is not affected (the control line and the switch are connected in series in the test circuit), the longer the line, the greater its internal resistance, and the greater the voltage it bears. This will affect the test voltage given to the test accessory in the test, and ultimately affect the entire test result. Compared with directly lengthening the test control line in the existing technology, when the electromagnet is attracted, the current directly reaches the output interface through the contacts of the electromagnetic relay to power the test accessory. This can greatly shorten the length of the test circuit and minimize the impact. Attached Figure Description

[0027] Figure 1 This is a circuit diagram of the power-on / off control system for testing the performance of aircraft air path accessories in the prior art.

[0028] Figure 2 This is a schematic diagram of the operation of the power-on / off control system for testing and evaluating the performance of aircraft gas path accessories in the prior art.

[0029] Figure 3 A circuit diagram of an embodiment of the power-on / off control system for testing and evaluating the performance of aircraft gas path accessories provided by this utility model;

[0030] Figure 4 A circuit diagram of an embodiment of the transmitter provided by this utility model;

[0031] Figure 5 A circuit diagram of an embodiment of the receiver provided by this utility model;

[0032] Reference numerals: 10-Electromagnetic relay; 110-Freewheeling diode; 20-Input interface; 30-Output interface; 40-Wireless remote control switch; 410-Transmitter; 4110-First switch; 4120-Third chip; 4130-Fourth chip; 420-Receiver; 4210-First chip; 4220-Second chip; 4230-Switching transistor; 50-Fuse; 60-Voltage regulation control module; 70-Changeover switch; 80-Wired control interface. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0034] It should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of this invention. It should be understood that the operations in the flowcharts may be implemented out of sequence, and steps without logical contextual relationships may be reversed or performed simultaneously. Furthermore, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor systems and / or microcontroller systems.

[0035] The terms "first," "second," etc., used in the embodiments of this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature specified with "first" or "second" may explicitly or implicitly include at least one of those features. "And / or" describes the relationship between related objects, indicating that three relationships may exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] This utility model provides a power-on / off control system for testing the performance of aircraft gas path accessories, which will be described below.

[0038] Figure 3 A schematic flowchart of an embodiment of the power-on / off control system for testing and evaluating the performance of aircraft gas path accessories provided by this utility model is shown below. Figure 3 As shown, the power-on / off control system for the performance test of aircraft air path accessories includes: an electromagnetic relay 10, an input interface 20, an output interface 30, a wireless remote control switch 40, and a first power supply.

[0039] One of the contacts of the electromagnetic relay 10 is connected to the test power supply through the input interface 20, and the other contact is connected to the accessory under test through the output interface 30, forming the first series circuit;

[0040] In some embodiments of this utility model, the electromagnetic relay 10 is a normally open electromagnetic relay 10, which can therefore carry a large current and better control the circuit. It should be noted that the selection of the electromagnetic relay 10 can be adjusted according to actual needs and is not limited to the normally open electromagnetic relay 10, which will not be elaborated here.

[0041] To improve safety, in some embodiments of this utility model, such as Figure 3 As shown, a fuse 50 is connected between the input interface 20 of the test power supply and the contacts of the electromagnetic relay 10 in the first series circuit. Therefore, when an unexpected situation occurs and the current is too large, the fuse 50 blows and the first series circuit is disconnected.

[0042] The coil of the electromagnetic relay 10 is connected to the first power source through the wireless remote control switch 40 to form a second series circuit. The wireless remote control switch 40 is used to receive a power-on control command to close or to receive a power-off control command to open.

[0043] Considering that when the power-on / off control system is connected to the test system, the voltage required for the test is provided by an external test power supply connected to the input interface 20, and since the tested accessory requires different test voltages at different stages, in order to ensure the stability of the power-on / off control system under different voltages, in some embodiments of this utility model, such as... Figure 3As shown, the first power supply is a voltage regulation control module 60. The input terminal of the voltage regulation control module 60 is connected to the output terminal of the input interface 20 of the test power supply. The voltage regulation control module 60 is used to convert the voltage input by the test power supply into a first preset voltage for output. The first preset voltage is 12V. This voltage regulation control module 60 provides a stable voltage for the electromagnetic relay 10 and the wireless remote control switch 40, ensuring the stability of executing power-on control commands and receiving power-off control commands during the test. Furthermore, using the test power supply as the power source for the electromagnetic relay 10 and the wireless remote control switch 40 can reduce costs. It should be noted that the selection of the first power supply can be adjusted according to actual needs, such as a battery, and is not limited to the test power supply and the voltage regulation control module 60. The selection of the first preset voltage can also be adjusted according to actual needs and is not limited to 12V. These details will not be elaborated here.

[0044] In some embodiments of this utility model, the voltage regulation control module 60 adopts a DC-DC converter. It should be noted that the selection of the voltage regulation control module 60 can be adjusted according to actual needs and is not limited to a DC-DC converter, which will not be elaborated here.

[0045] The wireless remote control switch 40 includes a transmitter 410 and a receiver 420, as described in some embodiments of this invention, such as... Figure 4 As shown, the transmitter 410 includes a second power source (not shown in the figure, but may be a battery), a first switch 4110, a third chip 4120, and a fourth chip 4130;

[0046] The second power supply is connected to the power input terminals of the third chip 4120 and the fourth chip 4130 via the first switch 4110;

[0047] The control output terminal of the third chip 4120 is connected to the control input terminal of the fourth chip 4130, and is used to output power-on control commands or power-off control commands transmitted in the form of electrical signals to the fourth chip 4130.

[0048] The fourth chip 4130 is used to amplify the power-on control command or power-off control command transmitted in the form of an electrical signal, and convert the amplified power-on control command or power-off control command transmitted in the form of an electrical signal into a power-on control command or power-off control command transmitted in the form of radio waves for transmission.

[0049] When in use, the first switch 4110 is turned on, the transmitter 410 circuit is connected, the second power supply supplies power to the third chip 4120 and the fourth chip 4130, and they start to operate. The resistance and voltage of pins 2, 4, 5, 6 and 8 of the third chip 4120 determine the frequency information emitted by pin 3 of the third chip 4120. The fourth chip 4130 then amplifies the information emitted by pin 3 of the third chip 4120 and transmits it.

[0050] In some embodiments of this utility model, such as Figure 5 As shown, receiver 420 includes a first chip 4210, a second chip 4220, and a switching transistor 4230;

[0051] The output terminal of the voltage regulation control module 60 is connected to the power supply input terminal of the first chip 4210 and the second chip 4220. The first chip 4210, the second chip 4220 and the switching transistor 4230 have a common ground terminal.

[0052] The control output terminal of the first chip 4210 is connected to the control input terminal of the second chip 4220, and is used to receive power-on control commands or power-off control commands transmitted in the form of radio waves, and convert the power-on control commands or power-off control commands transmitted in the form of radio waves into power-on control commands or power-off control commands transmitted in the form of electrical signals and transmit them to the second chip 4220.

[0053] The control output terminal of the second chip 4220 is connected to the control terminal of the switching transistor 4230. It is used to receive a power-on control command transmitted in the form of an electrical signal and output a second preset voltage to the control terminal of the switching transistor 4230, or to receive the power-off control command transmitted in the form of an electrical signal and output a third preset voltage to the control terminal of the switching transistor 4230. The third preset voltage is less than the second preset voltage.

[0054] The input and output terminals of the switching transistor 4230 are connected to the output terminal of the voltage regulation control module 60 through the coil of the electromagnetic relay 10 to form a second series circuit. When the control terminal voltage of the switching transistor 4230 reaches the second preset voltage, the channel inside the switching transistor 4230 is turned on.

[0055] When using, such as Figure 5 As shown, both the first chip 4210 and the second chip 4220 are IC chips. Since the frequency information of the signals received by the first chip 4210 is different, the signal given by the OUT pin of the first chip 4210 also changes differently. When the second chip 4220 receives the signal given by the OUT pin of the first chip 4210, it will compare it with the originally set signal (the calibration signal of the second chip 4220 is set by the resistance value, capacitance, etc. of pins 1, 2, 7, 6, and 5 of the second chip 4220, which is usually paired with the transmitter 410). When the signal is correct, pin 8 of the second chip 4220 gives a low voltage, which turns on the switching transistor 4230 and connects the coil power supply of the electromagnetic relay 10. Otherwise, it disconnects the coil power supply of the electromagnetic relay 10.

[0056] To prevent the reverse voltage generated by the coil when the electromagnetic relay 10 is de-energized from damaging the switching transistor 4230 and causing component failure, in some embodiments of this utility model, such as Figure 5As shown, a freewheeling diode 110 is connected in parallel across the coil of the electromagnetic relay 10. The positive terminal of the freewheeling diode 110 is connected to the negative terminal of the coil of the electromagnetic relay 10, and the negative terminal of the freewheeling diode 110 is connected to the positive terminal of the coil of the electromagnetic relay 10. Therefore, the freewheeling diode 110 can absorb the reverse electromotive force generated by the coil when the electromagnetic relay 10 is de-energized.

[0057] In summary, when the tested accessory needs to be powered on, the transmitter 410 is pressed remotely to send a power-on control command. The receiver 420 receives the power-on control command and controls the switch 4230 to conduct, the second series circuit to conduct, the first power supply to the coil of the electromagnetic relay 10 to supply power, the contacts of the electromagnetic relay 10 to close, the first series circuit to conduct, and the tested accessory to be powered on, thus completing the power-on control. When the tested accessory needs to be powered off, the transmitter 410 is pressed remotely to send a power-off control command. The receiver 420 receives the power-off control command and controls the switch 4230 to disconnect, the second series circuit to disconnect, the first power supply to the coil of the electromagnetic relay 10 to stop, the contacts of the electromagnetic relay 10 to open, the first series circuit to disconnect, and the tested accessory to be powered off, thus completing the power-off control. In this way, the tester no longer needs to directly contact the test and can indirectly control the test process from a distance or outside the test room, greatly improving the safety of the test. Furthermore, directly lengthening the test control line in the existing technology will affect the test parameters. As long as it is a wire, it will have resistance and produce a voltage division effect. According to Ohm's law, when the current is not affected (the control line and the switch are connected in series in the test circuit), the longer the line, the greater its internal resistance, and the greater the voltage it bears. This will affect the test voltage given to the test accessory in the test, and ultimately affect the entire test result. Compared with directly lengthening the test control line in the existing technology, when the electromagnet is attracted, the current passes through the contacts of the electromagnetic relay 10 and directly reaches the output interface 30 to power the test accessory. This can greatly shorten the length of the test circuit and minimize the impact.

[0058] To improve the fault tolerance of the system, in some embodiments of this utility model, such as Figure 3As shown, the output terminal of the voltage regulating control module 60 is connected to a changeover switch 70. The moving contact of the changeover switch 70 switches between a first stationary contact and a second stationary contact. The first stationary contact is connected to the coil of the electromagnetic relay 10 through the wired control interface 80 of the long-line switch. The voltage regulating control module 60, the long-line switch, and the coil of the electromagnetic relay 10 form a third series circuit through the first stationary contact. The second stationary contact is connected to the coil of the electromagnetic relay 10 through the wireless remote control switch 40. The voltage regulating control module 60, the switching transistor 4230, and the coil of the electromagnetic relay 10 form a second series circuit through the second stationary contact. Thus, when the wireless remote control switch 40 fails and cannot execute commands, the long-line switch is connected, and the output terminal of the changeover switch 70 is switched to the second stationary contact, which can replace the function of the wireless remote control switch 40 and achieve a wired control effect.

[0059] To better control the circuit, in some embodiments of this utility model, such as Figure 3 As shown, the changeover switch 70 is a two-pin changeover switch with two sets of moving contacts. Each set of moving contacts corresponds to two stationary contacts: the first stationary contact and the second stationary contact.

[0060] The above provides a detailed description of the power-on / off control system for testing the performance of aircraft air path accessories provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

[0061] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the scope of protection of this utility model.

Claims

1. An on-off electrical control system for aircraft air system accessory performance test, characterized by, Includes electromagnetic relays, wireless remote control switches, and a primary power supply; One of the contacts of the electromagnetic relay is used to connect to the test power supply, and the other contact is used to connect to the accessory under test, forming a first series circuit; The coil of the electromagnetic relay is connected to the first power source through the wireless remote control switch to form a second series circuit. The wireless remote control switch is used to receive a power-on control command to close the circuit or to receive a power-off control command to open the circuit.

2. The on-off electrical control system for aircraft air system accessory performance test of claim 1, wherein, The electromagnetic relay is a normally open type.

3. The on-off electrical control system for aircraft airpath accessory performance test testing according to claim 1, wherein, A freewheeling diode is connected in parallel across the coil of the electromagnetic relay. The positive terminal of the freewheeling diode is connected to the negative terminal of the coil of the electromagnetic relay, and the negative terminal of the freewheeling diode is connected to the positive terminal of the coil of the electromagnetic relay.

4. The on-off electrical control system for aircraft airpath accessory performance test testing according to claim 1, wherein, A fuse is also connected to the first series circuit.

5. The on-off electrical control system for aircraft airpath accessory performance test testing according to claim 1, wherein, The first power supply is a voltage regulation control module. The input terminal of the voltage regulation control module is connected to the output terminal of the test power supply. The voltage regulation control module is used to convert the voltage input by the test power supply into a first preset voltage for output.

6. The on-off electrical control system for aircraft airpath accessory performance test testing of claim 5, wherein, The voltage regulation control module uses a DC-DC converter.

7. The on-off electrical control system for aircraft air system accessory performance test of claim 1, wherein, The wireless remote control switch includes a transmitter and a receiver, and the receiver includes a first chip, a second chip, and a switching transistor; The transmitter is used to transmit power-on control commands or power-off control commands; The first power supply is connected to the power input terminals of the first chip and the second chip; The control output terminal of the first chip is connected to the control input terminal of the second chip, and is used to receive power-on control commands or power-off control commands transmitted in the form of radio waves, and convert the power-on control commands or power-off control commands transmitted in the form of radio waves into power-on control commands or power-off control commands transmitted in the form of electrical signals and transmit them to the second chip. The control output terminal of the second chip is connected to the control terminal of the switching transistor, and is used to receive the power-on control command transmitted in the form of an electrical signal and output a second preset voltage to the control terminal of the switching transistor, or to receive the power-off control command transmitted in the form of an electrical signal and output a third preset voltage to the control terminal of the switching transistor, wherein the third preset voltage is less than the second preset voltage. The input and output terminals of the switching transistor are connected to the first power supply through the coil of the electromagnetic relay to form the second series circuit. When the control terminal voltage of the switching transistor reaches the second preset voltage, the channel inside the switching transistor is turned on.

8. The on-off electrical control system for aircraft air system accessory performance test of claim 7, wherein, The transmitter includes a second power supply, a first switch, a third chip, and a fourth chip; The second power supply is connected to the power input terminals of the third chip and the fourth chip via the first switch; The control output terminal of the third chip is connected to the control input terminal of the fourth chip, and is used to output a power-on control command or a power-off control command transmitted in the form of an electrical signal to the fourth chip. The fourth chip is used to amplify the power-on control command or power-off control command transmitted in the form of an electrical signal, and convert the amplified power-on control command or power-off control command transmitted in the form of an electrical signal into a power-on control command or power-off control command transmitted in the form of radio waves for transmission.

9. The power-on / off control system for testing and evaluating the performance of aircraft gas path accessories according to claim 1, characterized in that, The first power supply is connected to a changeover switch. The moving contact of the changeover switch switches between a first stationary contact and a second stationary contact. The first stationary contact is connected to the coil of the electromagnetic relay via a long-line switch. The first power supply, the long-line switch, and the coil of the electromagnetic relay form a third series circuit through the first stationary contact. The second stationary contact is connected to the coil of the electromagnetic relay via a wireless remote control switch. The first power supply, the wireless remote control switch, and the coil of the electromagnetic relay form a second series circuit through the second stationary contact.

10. The on-off electrical control system for aircraft air system accessory performance test of claim 9, wherein, The selector switch is a two-pin selector switch.

Images