Transformer coil drying circuit system

Abstract

The utility model discloses a drying circuit system for a transformer coil. The drying circuit system comprises three-phase power supplies L1, L2 and L3 and a grounding wire PE, the system comprises a fan motor control loop, a heater control loop, a clamp control loop and a sequence control loop, the sequential control loop comprises a starting unit, a coil clamping control unit, a hot air drying control unit and a clamp separation control unit; the coil clamping control unit is used for controlling the electromagnetic valve EV1 to clamp a transformer coil; the hot air drying control unit is used for controlling a fan motor M1 and a heater R to start for drying operation; the clamp separation control unit is used for controlling the electromagnetic valve EV2 to be separated to complete the drying process. The drying device can ensure the drying quality of the transformer coil, improve the production efficiency and reduce the manual operation intensity.

Description

Technical Field

[0001] The utility model relates to electric power equipment manufacturing, in particular to a transformer coil drying circuit system, which is applied to the transformer coil drying process in the fields of industrial automation and electric power equipment manufacturing. Background Art

[0002] Transformers are crucial electrical equipment in power systems, and the insulation performance of their coil windings directly impacts the transformer's operational safety and service life. During transformer manufacturing, the coil windings often contain a certain amount of moisture, which can severely impact insulation performance. Therefore, thorough drying is essential. Transformer coil drying is a critical process in transformer manufacturing, directly impacting product quality and operational reliability.

[0003] Traditional transformer coil drying mostly adopts manual or semi-automatic operation mode. The operator needs to manually control the processes such as clamping of the fixture, starting and stopping of hot air drying, and disengaging of the fixture. This not only leads to low work efficiency, but also causes unstable drying quality due to human factors.

[0004] Therefore, it is of great practical value to develop a transformer coil drying circuit system that can automatically control the entire process of clamping, drying, and disengagement, has a complete start-up control and self-locking protection mechanism, ensures drying quality, and improves production efficiency. Utility Model Content

[0005] The purpose of the utility model is to provide a transformer coil drying circuit system, which can automatically control the work processes such as coil clamping, hot air drying and fixture separation, realize reliable startup and self-locking protection of the system through a starting unit, generate airflow through a fan motor, generate heat to form hot air through a heater, and control the fixture action through an electromagnetic valve, thereby ensuring the drying quality of the transformer coil, improving production efficiency and reducing the intensity of manual operation.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A transformer coil drying circuit system includes: three-phase power supplies L1, L2, L3 and a grounding wire PE, wherein the three-phase power supplies are connected to the system through a main circuit breaker QF; the system includes: a fan motor control circuit, a heater control circuit, a fixture control circuit and a sequence control circuit; wherein the fan motor control circuit includes a contactor KM1, a thermal relay FR1 and a fan motor M1; the heater control circuit includes a contactor KM2 and a heater R; the fixture control circuit includes a solenoid valve EV1 and a solenoid valve EV2; the sequence control circuit includes a starting unit, a coil clamping control unit, a hot air drying control unit and a fixture disengagement control unit; the coil clamping control unit is used to control the solenoid valve EV1 to clamp the transformer coil; the hot air drying control unit is used to control the fan motor M1 and the heater R to start and perform a drying operation; the fixture disengagement control unit is used to control the solenoid valve EV2 to disengage and complete the drying process.

[0008] The present invention is further configured as follows: the starting unit includes a push button switch SB1, a reset switch SB2 and a relay KA; the push button switch SB1 is used to start the system; the reset switch SB2 is connected to the coil of the relay KA; when the reset switch SB2 is pressed, the relay KA is energized, and its contacts A1-A2, 1-2, 3-4, and 5-6 are all closed; when the contacts A1-A2 are closed, the starting circuit is self-locked, ensuring that the relay KA remains energized.

[0009] The utility model is further configured as follows: the coil clamping control unit includes a time relay KT1 and a solenoid valve EV1; when the contacts 1-2 of the relay KA are closed, the coil of the time relay KT1 is energized and timing starts, and at the same time the solenoid valve EV1 is energized to control the clamp to clamp the transformer coil; the delay time of the time relay KT1 is set to 5-10 seconds, which is used to ensure that the coil is clamped in place and stable before starting subsequent processes.

[0010] The utility model is further configured as follows: the time relay KT1 has normally open contacts 17-18 and normally closed contacts 7-8; when the delay of the time relay KT1 ends, its normally open contacts 17-18 are closed, and the subsequent process is started; its normally closed contacts 7-8 are disconnected, and the clamp clamping the transformer coil no longer operates.

[0011] The present utility model is further configured as follows: the hot air drying control unit includes a time relay KT2, a contactor KM1, a contactor KM2, a fan motor M1 and a heater R; the normally open contacts 17-18 of the time relay KT1 are connected to the coil circuit of the time relay KT2, the coil circuit of the contactor KM1 and the coil circuit of the contactor KM2; the main contacts of the contactor KM1 are connected to the fan motor M1, for driving the fan motor to generate airflow; the main contacts of the contactor KM2 are connected to the heater R, for controlling the heater to generate heat and perform hot air drying on the clamped transformer coil.

[0012] The utility model is further configured as follows: the time relay KT2 has normally open contacts 19-20 and normally closed contacts 9-10 and 11-12; when the delay of the time relay KT2 ends, its normally open contacts 19-20 are closed, and the starting fixture is disengaged from the control unit; its normally closed contacts 9-10 are disconnected to cause the contactor KM1 to lose power, and the normally closed contacts 11-12 are disconnected to cause the contactor KM2 to lose power, thereby stopping the fan motor M1 and the heater R from drying.

[0013] The utility model is further configured as follows: the clamp detachment control unit includes a time relay KT3 and a solenoid valve EV2; the normally open contacts 19-20 of the time relay KT2 are connected to the coil circuit of the time relay KT3 and the solenoid valve EV2; the solenoid valve EV2 is used to control the clamp to detach from the transformer coil; the delay time of the time relay KT3 is set to 3-5 seconds to ensure that the clamp is completely detached from the coil.

[0014] The utility model is further configured as follows: the time relay KT3 has normally closed contacts 13-14 and normally closed contacts 15-16; when the delay of the time relay KT3 ends, its normally closed contacts 13-14 are disconnected, and the clamp no longer moves; its normally closed contacts 15-16 are disconnected, the relay KA is powered off, the entire control circuit is powered off, and a complete drying cycle is completed.

[0015] The utility model is further configured as follows: the system further includes a protection unit; the protection unit includes a thermal relay FR1, which is used to monitor the operating current of the fan motor M1 and cut off the power supply in the event of an overload, thereby protecting the motor from damage.

[0016] The present invention is further configured as follows: the time relay KT1 is an energized delay type relay, which is used to control the clamping time of the electromagnetic valve EV1, ensuring that the transformer coil is firmly clamped before starting the subsequent process.

[0017] The utility model is further configured as follows: the time relay KT2 is an energized delay type relay, which is used to control the drying time of the fan motor M1 and the heater R. The delay time is determined according to the coil specifications and moisture content, and is set to 30-120 minutes to ensure that the transformer coil is fully dried.

[0018] The present invention is further configured as follows: the time relay KT3 is an energized delay type relay, which is used to control the time for the electromagnetic valve EV2 to disengage, so as to ensure that the clamp is completely separated from the transformer coil.

[0019] The utility model is further configured as follows: the fan motor M1 is a three-phase asynchronous motor, powered by a three-phase power supply L1, L2, and L3; the U1, V1, and W1 terminals of the motor are connected to the three-phase power supply through the thermal relay FR1 and the main contacts of the contactor KM1; the motor casing is grounded through the PE terminal; the heater R is connected to the three-phase power supply through the main contacts of the contactor KM2 to ensure safe operation of the equipment.

[0020] The utility model is further configured as follows: the solenoid valve EV1 and the solenoid valve EV2 respectively control the clamping and disengaging actions of the clamp, and the solenoid valve realizes the mechanical movement of the clamp by controlling the pneumatic system, thereby ensuring the stable clamping of the transformer coil during the drying process and the reliable disengagement after the drying is completed.

[0021] The present invention is further configured as follows: the reset switch SB2 adopts a self-reset design, which automatically pops up after being pressed to avoid misoperation; the relay KA has a self-locking function to ensure that the control circuit maintains a stable power-on state during operation.

[0022] In summary, the present invention has the following beneficial effects:

[0023] High reliability of startup control: The system is equipped with a startup unit, including push button switch SB1, reset switch SB2 and relay KA. The self-locking function of relay KA ensures stable operation of the system after startup. The reset switch SB2 adopts a self-resetting design to effectively avoid misoperation and improve the reliability and safety of the system.

[0024] High degree of automation: The system utilizes a sequential control loop to fully automate coil clamping, hot air drying, and fixture disengagement. The operator simply presses the start button SB1 and the reset switch SB2 to complete a full cycle, reducing manual labor and improving work efficiency and convenience. Compared to traditional manual control methods, the system boasts an automation level of over 85%.

[0025] High drying quality: The system uses time relays KT1, KT2 and KT3 to accurately control the time of each process, and uses solenoid valves EV1 and EV2 to accurately control the clamping force. The change in the contact state of the time relay ensures the precise connection between each process and ensures that the clamping force, drying time and separation process of each transformer coil are completely consistent, overcoming the problem of difficulty in ensuring consistency in manual operation and improving product quality stability.

[0026] High efficiency in generating hot air: The system uses a combination of a fan motor M1 and a heater R to generate hot air. The fan motor provides sufficient air volume, and the heater provides stable heat. The two work in coordination to form hot air with suitable temperature and sufficient air volume, which improves drying efficiency and reduces energy consumption compared to a single heat source method.

[0027] High clamp control precision: Solenoid valves EV1 and EV2 are used to control the clamp movement, and precise mechanical movement is achieved through the pneumatic system. Compared with the traditional mechanical manual clamping method, the clamping force is more uniform and stable. The clamping parameters can be adjusted according to coils of different specifications, effectively avoiding problems such as damage to the coil due to over-tight clamping or impact of positioning accuracy due to over-loose clamping.

[0028] Reliable safety protection: The system integrates a complete protection mechanism, including thermal relay FR1 for overload protection of the fan motor, main circuit breaker QF for main power protection, self-locking and reset functions of relay KA for startup protection, and time relay KT3 for automatic reset of the system. Multiple protection mechanisms effectively prevent equipment damage and safety accidents.

[0029] Precise process connection: Through the cascade control and precise conversion of contact states of time relays KT1, KT2 and KT3, the system realizes the precise connection of processes such as coil clamping, hot air drying and fixture separation. The conversion between each process is accurate and timely, avoiding the delay and instability of process switching in traditional manual control, and shortening the entire drying cycle time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the circuit principle diagram of the transformer coil drying circuit system of the utility model. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0033] like Figure 1 As shown, the transformer coil drying circuit system provided by this utility model includes three-phase power supplies L1, L2, and L3 and a grounding line PE, which are connected to the system through a main circuit breaker QF. The system mainly consists of four parts: the fan motor control circuit, the heater control circuit, the fixture control circuit, and the sequence control circuit.

[0034] The fan motor control circuit consists of contactor KM1, thermal relay FR1, and fan motor M1. Fan motor M1 is a three-phase asynchronous motor with a rated power of typically 1.5-3 kW. It is connected to the three-phase power supply via the main contacts of contactor KM1. Thermal relay FR1 is connected in series with fan motor M1 to monitor the motor's operating current and automatically disconnect the circuit if the motor is overloaded, protecting the motor from damage. The fan motor's casing is grounded via the PE terminal to ensure safe operation. The fan motor's primary function is to drive the centrifugal fan, generating a stable airflow and providing sufficient air volume for the drying process.

[0035] The heater control circuit consists of contactor KM2 and heater R. Heater R is a resistive heater, typically rated at 3-6 kW, and is connected to a three-phase power supply via the main contacts of contactor KM2. Heater R converts electrical energy into thermal energy, heating the passing air. This heat, combined with the airflow generated by fan motor M1, creates hot air. Heater R has a temperature control function, adjusting the heating temperature according to drying requirements. Its typical operating temperature is controlled within the range of 80-120°C.

[0036] The fixture control circuit includes solenoid valves EV1 and EV2. EV1 is the clamping solenoid valve, controlling the fixture's clamping action; EV2 is the disengagement solenoid valve, controlling the fixture's disengagement action. The solenoid valves control the pneumatic system to achieve the fixture's mechanical motion.

[0037] The sequential control loop includes a starting unit, a coil clamping control unit, a hot air drying control unit and a clamp disengagement control unit.

[0038] The starting unit includes a pushbutton switch SB1 and a reset switch SB2. The operator starts the system by pressing pushbutton switch SB1. Reset switch SB2 is connected to relay KA. Pressing reset switch SB2 energizes relay KA, closing its contacts A1-A2, 1-2, 3-4, and 5-6. This closure of contacts A1-A2 self-locks the starting circuit, ensuring relay KA remains energized.

[0039] The coil clamping control unit consists of pushbutton switch SB1, time relay KT1, and solenoid valve EV1. When contacts 1-2 of relay KA close, the coil of time relay KT1 is energized and timing begins. Simultaneously, solenoid valve EV1 is energized, controlling the clamp to clamp the transformer coil. The delay time of time relay KT1 is typically set to 5-10 seconds to ensure the coil is clamped and stabilized before starting subsequent processes.

[0040] The hot air drying control unit consists of time relay KT2, contactor KM1, and contactor KM2. When the coil is clamped and the time delay of time relay KT1 expires, normally closed contacts 7-8 open, the clamp no longer clamps the transformer coil, and its normally open contacts 17-18 close. Time relay KT2, contactor KM1, and the coils of contactor KM2 are energized simultaneously. Contactor KM1's main contacts close, and fan motor M1 begins operating, generating a stable airflow. Contactor KM2's main contacts close, and heater R begins operating, heating the airflow. The fan motor and heater work in coordination, generating hot air at an ideal temperature to dry the clamped transformer coil. The time delay of time relay KT2 is determined by the coil specifications and moisture content and is generally set between 30 and 120 minutes.

[0041] The fixture disengagement control unit includes time relay KT3 and solenoid valve EV2. When drying is complete and the time delay of time relay KT2 expires, its normally closed contacts 9-10 open, relay KM1 loses power, normally closed contacts 11-12 open, relay KM2 loses power, and both fan motor M1 and heater R are de-energized. Its normally open contacts 19-20 close, energizing the coil of time relay KT3 and solenoid valve EV2 simultaneously. Solenoid valve EV2 activates, controlling the fixture to release the transformer coil. The time delay of time relay KT3 is typically set to 3-5 seconds to ensure complete disengagement of the fixture coil.

[0042] When the separation is completed and the delay of time relay KT3 ends, its normally closed contacts 13-14 are disconnected, and the clamp no longer moves. At the same time, normally closed contacts 15-16 are disconnected, relay KA is de-energized, and the entire control circuit is de-energized. The system completes a complete drying cycle and automatically resets, ready for the next drying cycle.

[0043] The overall workflow of the system is as follows:

[0044] Preparation stage: The operator places the transformer coil to be dried on the fixture station, checks whether the coil is correctly positioned, then turns on the power supply and closes the main circuit breaker QF. The system is in standby mode. At this time, all contactors and solenoid valves are in the power-off state, and all time relays are in the reset state.

[0045] Startup Phase: The operator presses pushbutton switch SB1 to start the system. Pressing reset switch SB2 energizes relay KA, connecting the control circuit. Simultaneously, the coil of time relay KT1 energizes and begins timing, officially beginning system operation. Reset switch SB2 is self-resetting and automatically pops up when pressed, preventing accidental operation.

[0046] Clamping phase: Time relay KT1 energizes, activating solenoid valve EV1, controlling the pneumatic system to push the clamp to grip the transformer coil. The clamp utilizes a multi-point symmetrical clamping method, and the clamping force can be controlled by adjusting the air pressure to ensure a secure and damage-free clamping of the coil. Time relay KT1 begins counting, with a delay of 5-10 seconds to ensure complete clamping.

[0047] Drying stage: When the delay of time relay KT1 ends, normally open contacts 17-18 close and normally closed contacts 7-8 open, so that the coils of time relay KT2, contactor KM1 and contactor KM2 are energized at the same time. The main contact of contactor KM1 closes, and fan motor M1 starts to work, driving the centrifugal fan to generate a stable airflow. The air volume is generally controlled at 500-1000m 3 / h; the main contacts of contactor KM2 close, and heater R begins operating, heating the passing air at a controlled temperature of 80-120°C. The fan and heater work in coordination to generate hot air at an appropriate temperature and sufficient volume, which is blown directly through the air duct to the clamped transformer coil, achieving efficient drying. Time relay KT2 also begins timing, with the delay time set based on the coil specifications, moisture content, and drying requirements, generally ranging from 30 to 120 minutes.

[0048] Disengagement Phase: When the delay of time relay KT2 expires, normally closed contacts 9-10 and 11-12 open. Normally open contacts 19-20 close, simultaneously energizing the coil of time relay KT3 and solenoid valve EV2. Solenoid valve EV2 activates, controlling the fixture's separation from the transformer coil. The separation process uses a slow retraction method to avoid impacting the dried coil. Time relay KT3 begins timing, with a delay of 3-5 seconds to ensure the fixture is completely separated from the coil.

[0049] Reset completion phase: When the delay of time relay KT3 ends, its normally closed contacts 15-16 open, de-energizing the entire control circuit, and the system completes a full drying cycle. All contactors and solenoid valves are de-energized and reset, and the time relays automatically reset. The system returns to its initial state, ready for the next drying cycle. The operator can then remove the dried transformer coil, insert a new coil to be dried, and repeat the above process.

[0050] The corresponding parameter settings in this application are as follows:

[0051] The delay time of time relay KT1 determines the clamping time and needs to be adjusted according to the fixture type and coil specifications. For small coils (diameter less than 200mm), the delay time is set to 5 seconds; for medium coils (diameter 200-500mm), the delay time is set to 7 seconds; for large coils (diameter greater than 500mm), the delay time is set to 10 seconds.

[0052] The drying time is determined by the delay time of time relay KT2 and needs to be adjusted according to the moisture content of the coil, the type of insulation material, and the drying requirements. Generally, the drying time for paper-insulated coils is 60-90 minutes, the drying time for oil-paper-insulated coils is 90-120 minutes, and the drying time for epoxy-insulated coils is 30-60 minutes.

[0053] The delay time of time relay KT3 determines the disengagement time, which must ensure that the fixture can completely disengage from the coil without colliding with it. It is generally set to 3-5 seconds, and the specific time can be fine-tuned based on the mechanical characteristics of the fixture.

[0054] The power and speed of the fan motor M1 need to be determined according to the drying capacity. Generally, a 1.5-3kW three-phase asynchronous motor with a speed of 1450rpm is selected, which can generate 500-1000m 3 / h air volume.

[0055] The power of heater R needs to be determined based on the required heat. Generally, a 3-6kW resistance heater is selected. The heating temperature can be adjusted in the range of 60-150℃, and the normal operating temperature is 80-120℃.

[0056] The selection of solenoid valves EV1 and EV2 needs to be determined according to the driving mode of the fixture. For pneumatic fixtures, pneumatic solenoid valves with a working pressure of 0.4-0.8MPa are selected.

[0057] This utility model's transformer coil drying circuit system utilizes a relay logic control structure, boasting a simple circuit, high reliability, and easy maintenance. Compared to traditional manual or semi-automatic drying methods, this utility model achieves fully automated control, improving production efficiency while ensuring consistent drying quality. The system utilizes a combination of a fan motor and heater to generate hot air, achieving higher efficiency and lower energy consumption than a single heat source. A solenoid valve controls the clamping force, enabling precise control of the clamping force and effectively protecting the transformer coil.

[0058] The utility model can be widely used in the drying treatment of transformer coils of various specifications. By adjusting the delay parameter of the time relay, the temperature setting of the heater and the pressure parameter of the solenoid valve, the processing needs of coils with different specifications and drying requirements can be adapted.

[0059] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A transformer coil drying circuit system, characterized in that: include: Three-phase power supply L1, L2, L3 and grounding wire PE, the three-phase power supply is connected to the system through the main circuit breaker QF; the system includes: a fan motor control circuit, a heater control circuit, a fixture control circuit and a sequential control circuit; wherein, the fan motor control circuit includes a contactor KM1, a thermal relay FR1 and a fan motor M1; the heater control circuit includes a contactor KM2 and a heater R; the fixture control circuit includes a solenoid valve EV1 and a solenoid valve EV2; the sequential control circuit includes a starting unit, a coil clamping control unit, a hot air drying control unit and a fixture disengagement control unit; the coil clamping control unit is used to control the solenoid valve EV1 to clamp the transformer coil; the hot air drying control unit is used to control the fan motor M1 and the heater R to start and perform the drying operation; the fixture disengagement control unit is used to control the solenoid valve EV2 to disengage and complete the drying process.

2. The transformer coil drying circuit system according to claim 1, characterized in that: The starting unit includes a push button switch SB1, a reset switch SB2 and a relay KA; the push button switch SB1 is used to start the system; the reset switch SB2 is connected to the coil of the relay KA; when the reset switch SB2 is pressed, the relay KA is energized and its contacts A1-A2, 1-2, 3-4, and 5-6 are all closed; when the contacts A1-A2 are closed, the starting circuit self-locks, ensuring that the relay KA remains energized.

3. The transformer coil drying circuit system according to claim 2, characterized in that: The coil clamping control unit includes a time relay KT1 and a solenoid valve EV1; when the contacts 1-2 of the relay KA are closed, the coil of the time relay KT1 is energized and timing begins, and at the same time, the solenoid valve EV1 is energized to control the clamp to clamp the transformer coil; the delay time of the time relay KT1 is set to 5-10 seconds to ensure that the coil is clamped in place and stable before starting subsequent processes.

4. The transformer coil drying circuit system according to claim 3, characterized in that: The time relay KT1 has normally open contacts 17-18 and normally closed contacts 7-8; when the time relay KT1 delay ends, its normally open contacts 17-18 are closed, starting the subsequent process; its normally closed contacts 7-8 are disconnected, and the clamp clamping the transformer coil no longer operates.

5. The transformer coil drying circuit system according to claim 4, characterized in that: The hot air drying control unit includes a time relay KT2, a contactor KM1, a contactor KM2, a fan motor M1 and a heater R; the normally open contacts 17-18 of the time relay KT1 are connected to the coil circuit of the time relay KT2, the coil circuit of the contactor KM1 and the coil circuit of the contactor KM2; the main contacts of the contactor KM1 are connected to the fan motor M1, used to drive the fan motor to generate airflow; the main contacts of the contactor KM2 are connected to the heater R, used to control the heater to generate heat and perform hot air drying on the clamped transformer coil.

6. The transformer coil drying circuit system according to claim 5, characterized in that: The time relay KT2 has normally open contacts 19-20 and normally closed contacts 9-10 and 11-12; when the delay of the time relay KT2 ends, its normally open contacts 19-20 close, and the starting fixture disengages from the control unit; its normally closed contacts 9-10 are disconnected to de-energize the contactor KM1, and the normally closed contacts 11-12 are disconnected to de-energize the contactor KM2, thereby stopping the fan motor M1 and the heater R from drying.

7. The transformer coil drying circuit system according to claim 6, characterized in that: The fixture detachment control unit includes a time relay KT3 and a solenoid valve EV2; the normally open contacts 19-20 of the time relay KT2 are connected to the coil circuit of the time relay KT3 and the solenoid valve EV2; the solenoid valve EV2 is used to control the fixture to detach from the transformer coil; the delay time of the time relay KT3 is set to 3-5 seconds to ensure that the fixture is completely detached from the coil.

8. The transformer coil drying circuit system according to claim 7, characterized in that: The time relay KT3 has normally closed contacts 13-14 and normally closed contacts 15-16; when the time relay KT3 delay ends, its normally closed contacts 13-14 are disconnected, and the clamp no longer moves; its normally closed contacts 15-16 are disconnected, the relay KA is de-energized, the entire control circuit is de-energized, and a complete drying cycle is completed.

Images