Power Relay is a device that can generate a jump in the output circuit of one or more electrical appliances when the input quantity (or excitation quantity) meets certain prescribed conditions, and can be used in a direct neutral grounding system. Directional element for zero sequence current protection. What is its role in the industrial control system? The minimum current that a relay can produce to actuate. What is the role of power relays in industrial control systems? Power Relay Manufacturer to tell you.
As a control element, in summary, the relay has the following functions:
1) Expand the scope of control. For example, when the control signal of the multi-contact relay reaches a certain value, the multi-circuit can be switched, disconnected and connected at the same time according to different forms of the contact group.
2) Amplification: For example, sensitive relays, intermediate relays, etc., can control very large power circuits with a very small amount of control.
3) Comprehensive signals. For example, when a plurality of control signals are input to a multi-winding relay in a prescribed form, after comparison and synthesis, a predetermined control effect is achieved.
4) Automatic, remote control and monitoring. For example, the relays on the automatic device, together with other electrical appliances, can form a program control circuit to achieve automatic operation.
In normal use, the given current must be slightly larger than the pull-in current, so that the relay can work stably. As for the working voltage applied to the coil, generally do not exceed 1.5 times the rated working voltage, otherwise a larger current will be generated and the coil will be burned.
Applications in home appliances such as air conditioners often use power relays. In recent years, high-power household appliances have developed rapidly, such as electric water heaters, water dispensers, etc., all use this type of relay.
Because of the three-phase high-power contactors available in the industry, it is relatively rare. Compared with the commonly used contact capacity of 3-5A, there are also larger models such as the capacity of 7A, and the difference between 10A is not so obvious.
In use, its contact action process can be divided into two parts: contact closing and contact opening, that is, the pull-in and release processes of the relay. They are cyclically switched at a certain frequency to form the contact opening and closing phenomenon. In the process of contact closure and opening, there are many special physical and chemical phenomena, such as contact resistance, contact jitter and arc.
The maximum current that the relay generates for a release action. When the current in the relay pull-in state is reduced to a certain level, the relay will return to the release state without power. The current at this time is much smaller than the pull-in current.
The contacts switch voltage and current.
The voltage and current that the relay allows to load. It determines the size of the voltage and current that the relay can control. It cannot exceed this value when it is used, otherwise the contacts of the relay will be easily damaged.
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