Tag: relay

In power systems, switches allow the system operators to disconnect or connect electrical circuits. Switches come in various configurations among which there are several specialized forms, such as relays and circuit breakers. Though in more precise terms, relays are controlling devices while circuit breakers are switching devices.

In general, solid state relays are quite similar to the mechanical relays that have movable contacts. The main difference between both is the fact that there are no actual moving components in an SSR, just like the name suggests. Rather than relying on a physical contact moving to complete the circuit, solid state relays (SSR) employ optical semiconductor switching elements, such as diodes, thyristors, triacs and transistors. In this article, ATO automation will explore these two typical relays and find out more about their differences. 

Thermal overload relays are protective appliances used for overload protection of motors or other electrical equipment and electrical lines. In the actual operation of the motor, for example, in the process of dragging the production machinery to work, if the machinery is abnormal or the circuit is abnormal and the motor is overloaded, the motor speed will drop and the current in the winding will increase, which will make the winding temperature of the motor. If the overload current is not large and the overload time is short, and the motor winding does not exceed the allowable temperature rise, this overload is allowed.

A relay is an electrical control device, which is an electrical appliance that makes a predetermined step change of the controlled quantity in the electrical output circuit when the change of the input quantity meets the specified requirements. It has the interactive relationship between the control system and the controlled system. Usually used in automatic control circuits, a relay is actually an automatic switch that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

Thermal overload relays are overload relays that apply the principle of current thermal effect and use electrical thermal bimetallic sheets as sensitive components. The electrical thermal bimetal sheet is made by heating and rolling two alloys with large difference in linear expansion coefficient. When heated, the bimetallic sheet bends from the high expansion layer to the low expansion layer. When the current is too large, the element acts due to "heat", so that its linked moving contact cuts off the power supply of the controlled circuit and the protected equipment.

The dedicated solid state relay has the functions of short circuit protection, overload protection and overheat protection. It can realize the intelligent module required by the user and directly use it in the control system with the combination logic curing package. SSR can use external analog signal to trigger the module to achieve linearly adjustable output voltage.

A solid state relay is an all-electronic circuit combination component that relies on the electromagnetic and optical properties of semiconductor devices and electronic components to complete its isolation and relay switching functions. Compared with the traditional electromagnetic relay, the solid state relay is a relay without machinery and no moving parts, but has essentially the same function as the electromagnetic relay.

Solid state relay, short for SSR, is a non-contact switch composed of microelectronic circuits, discrete electronic devices, and power electronic power devices. The isolation device is used to realize the isolation between the control terminal and the load terminal. The input end of the solid state relay uses a tiny control signal to directly drive a large current load. So, how to maintain a solid state relay?

The working principle of electromagnetic relay is that when the electromagnet is energized, the armature is sucked down to make the two contacts, and the working circuit is closed. When the electromagnet loses its magnetism, the spring pulls the armature up, cutting off the working circuit. It is usually used in automatic control circuits. It is actually an automatic switch that uses a smaller current to control a larger current, so it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

Modern industrial automated machinery is powered mostly by motors. The torque generated from a rotating motor provides the driving force for moving conveyor belts, gears, chains and other mechanical components, so a motor naturally becomes such an integral part that is key to the driving system. When it comes to the protection of the core power part, you can't pay too much attention to it. Thermal overload relays are used to provide overload protection, open-phase protection and protection against the unbalanced current for motors and they can also avoid heating in electrical equipment. The thermal overload relay works by the thermal effect of electric current to push the action mechanism to make or break contacts for the protection of electrical appliances.

When an electrical circuit has two contactors and only one of them needs to be turned on at a time then the interlocking system is used. The interlocking system ensures that only one contactor can be on while another one will be in off condition even if we try to manually on.

A PLC takes in inputs, whether from automated data capture points or from human input points such as switches or buttons. Based on its programming, the PLC then decides whether or not to change the output. A PLC's outputs can control a huge variety of equipment, including motors, solenoid valves, lights, switchgear, safety shut-offs and many others.

Programmable relay stores some typical relay logic control program in internal memory in advance and realize some simple logic control and sequence control function by the user program combination and calls. The user program uses the ladder diagram or functional diagram language through panel, intuitive and easy to understand. The switching signal input by the button, switch etc.

Relays are an electronic control device with a control system (that is, an input loop) and a controlled system (output loop), and are usually used in automated control circuits. The relay is actually an "automatic switch" that uses a small current to control the operation of a large current. It plays the role of conversion circuit, automatic adjustment and safety protection in the circuit.

Programmable relay stores some typical relay logic control program in internal memory in advance and realize some simple logic control and sequence control function by the user program combination and calls. Its integrated internal software function and programming software can replace the traditional relay logic circuit, such as the logic circuit composed of relay, contactor and timer, and has a strong anti-interference ability. Therefore, programmable relay is widely used in industrial automation control system, small machinery and devices, building electrical and other fields. It is applicable to the control of intelligent residence system, lighting system, heating and ventilation system, door, window, fence and moving door.

A monitoring relay is a commonly used electromagnetic relay that is used for the voltage protection and control of the power drag system. The coil is connected to the main circuit in parallel to sense the line voltage of the main circuit; the contact is connected to the control circuit and is the executive element. According to the size of the pull-in voltage, voltage monitoring relays can be divided into over-voltage relays and under-voltage relays. ATO monitoring relay has a great many function, including overvoltage protection, undervoltage protection, voltage unbalance protection, phase failure protection and wrong phase protection.

ATO time relay is a very important component in the electrical control system. In many control systems, time relays are required to implement time delay control. It is an automatic control electrical appliance that uses the principle of electromagnetic or mechanical action to delay the closing or breaking of contacts. Its characteristic is that there is a delay from the time when the attracting coil gets the signal to the action of the contact, which is generally used for the motor starting process control with time as a function.

A relay is an electrical control device. When the change of the input quantity (excitation quantity) reaches the specified requirements, the relay makes a predetermined step change of the controlled quantity in the electrical output circuit. It has an interactive relationship between the control system (also known as the input loop) and the controlled system (also known as the output loop). Usually used in automatic control circuits, it is actually an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit. Relays are widely used in industry. Therefore, today we will introduce the structure, function and classification of relays. We hope that after reading this article, you can have a general idea of relays.

A relay is an electrical control device, which is an electrical appliance that makes a predetermined step change of the controlled quantity in the electrical output circuit when the change of the input quantity meets the specified requirements. It has the interactive relationship between the control system and the controlled system. Usually used in automatic control circuits, it is actually an "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.