In the integrated wiring project, there are many need to use the parts, in addition to master the relevant integrated wiring skills, for the integrated wiring need to use the parts also need to understand.For example, what is a relay and how the relay wiring.

What is a relay

Relay (English name: relay) is an electrical control device, is when the change of input (excitation) to reach the specified requirements, in the electrical output circuit to make the controlled amount of a predetermined step change.

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 a small current to control the operation of a large current of an "automatic switch."Therefore in the circuit plays the role of automatic regulation, safety protection, conversion circuit and so on.

How to wire relays

Because the main purpose of the application of relays is to control strong current with weak current.(including low voltage control high voltage, small current control large current).The realization of the action is through the control of its own coil power off, so that its contact power off.(in layman's terms, the magnet pulls or doesn't pull, and the magnet controls the contact switch)

Therefore, the connector of relay includes the contact connector of its control circuit and the connector of its control coil.

Intermediate relay contacts have a certain load capacity, when the load capacity is relatively small, can be used to replace the use of small contactors, such as electric shutter and some small appliances control.This advantage is not only can play the purpose of control, and can save space, so that the control part of the electrical appliances do more delicate.

This is the most common use of intermediate relays, for example, when the contact of one contactor in a circuit control system needs to control more than one contactor or other element and an intermediate relay is added to the circuit.As we know, although the contact capacity of the intermediate relay is not very large, it also has a certain load capacity, and the current required for its drive is very small, so the intermediate relay can be used to expand the contact capacity.

For example, can not directly use the induction switch, the output of the transistor to control the load is relatively large electrical components.Instead, intermediate relays are used in the control circuit to control other loads, so as to expand the control capacity.

In the industrial control circuit, such a situation often occurs, the control requirements need to use the contactor normally closed contact to achieve the purpose of control, but the contactor itself with the normally closed contact has been used up, unable to complete the control task.

At this time, an intermediate relay can be connected in parallel with the original contactor coil, and the normally closed contact of the intermediate relay can be used to control the corresponding elements, and the contact type can be converted to achieve the desired control purpose.

In some control lines, some electrical components often use intermediate relay, with its contact open and close to control, such as color TV or monitor in common automatic degaussing circuit, transistor control intermediate relay on and off, so as to control the degaussing coil on and off.

Eliminate interference in circuits: in industrial or computer controlled circuits, though there are various.Intermediate relay function is used to transmit signals or control multiple circuits at the same time, can also be directly used to control a small capacity motor or other electrical executive components, its structure and ac contactor is basically the same, but the electromagnetic system is smaller, more contacts.

How to select relay

Thermal relay the electrical components, I believe most of the electric power technical staff are all very understand, the main purpose of the thermal relay is applied in the motor control circuit, the motor overload protection, or other equipment when the circuit or equipment overload problems, thermal relay will disconnect circuit, to achieve the effect of protection.

A lot of the master that just begins to learn electrician to feel not simple, very easy confuse, today we will use the most popular language to understand thermal relay, focus on the thermal relay A lot of the master that just begins to learn electrician to feel not simple, very easy confuse, today we will use the most popular language to understand thermal relay, focus on the thermal relay how to judge good or bad?

Thermal relay important parameters: generally speaking there are three points, thermosensitive elements, normally open point NO and normally closed point NC, manual automatic reset knob!When the circuit or equipment overload fault, the thermal sensor will produce deformation, can make the thermal relay normally open point NO closed, normally closed point NC disconnected, usually we use NO normally open point as a fault alarm signal, normally closed point NC as a disconnect control circuit use!After the action of thermal relay, you can choose manual reset or automatic reset!

We judge the quality of thermal relay mainly through the above three attributes:

1，The thermal sensor should be on at all times, the multimeter gear should be adjusted to diode or buzzer, the measurement should be on, the thermal sensor is measured as follows:

2，Measurement of normally open point NO and normally closed point NC

Note: the gear position of the multimeter is also a diode file or a buzzer file. The normally open point NO is disconnected under normal conditions, while the normally closed point NC is closed under normal conditions

This is the normal state of the thermal relay. Next, manually simulate the protection state of the thermal relay and turn the overload protection switch to the action state:

3，After overload protection action of thermal relay, manual reset and automatic reset can be selected. Taking manual reset as an example, we need to measure the change of contact after reset:

Conclusion: the above measurement, if is normal, we can roughly think thermal relay is good, remind everybody, thermal relay can choose manual reset and automatic reset, if it is automatic reset, and don't need to pipe it in practical application, thermal relay will return to original working condition, the next protection, if it is a manual reset, must be manually reset button (red button in the above picture), can be the next overload protection!

What is a relay?How are the relays wired?Believe you see here have had certain understanding, actually relay is an electronic control device, it has a control system (also called input circuit) and control system (also called the output circuit), usually used in automatic control circuit, it is actually with less current to control large current of a kind of "automatic switch".Therefore in the circuit plays the role of automatic regulation, safety protection, conversion circuit and so on.