Deep Talk about Magnetic Latching Relay
Recently, many people inquired the application and usage of latching relay by sending message, so Let’s do an exposition on two aspects for this issue.
Magnetic latching relay, like ordinary relay, is a kind of automatic switch, which generates magnetic field by electrifying the internal coil, and then drives the transition of stable state of contact according to the permanent magnet with polarity, so as to realize the switching on and off of circuit.Because of the permanent magnet and its internal mechanical structure, the coil of the magnetic latching relay does not need to be energized all the time, but only needs to be energized during a short period of time when the contact is converted.If the ordinary relay needs to keep the current contact state by energizing all the time, on the one hand, it will increase the power consumption of the control part, because the coil has a certain power consumption in the energized state; on the other hand, the relay coil will generate a certain amount of heat for a long time energized, which will affect the life of the relay.This indicates that magnetic latching relay is more suitable for some occasions that require low power consumption of control circuit or relay contact conversion is not particularly frequent.
Magnetic latching relays are mainly used for electric meters nowadays, a lot of meters are meters with multi-tariff, prepaid or postpaid are generally have a remote or local control, the control of when electric meter delay the bill or are some anomalies such as cover open events, the owner can control power meters. Another common application scenario is ev charging pile, which is basically similar to the application principle in electricity meter, because charging pile also does not need frequent on-off circuit.
Magnetic Latching relay coils are generally divided into two types, namely single coil and double coil. It is known that the polarity of the magnetic field of the coil will change according to the polarity of the voltage when the DC current passes through the coil, and the internal mechanical structure will undergo different transformation by using the magnetic field change. A single coil, which is a coil inside the relay, changes the state of the contact directly by converting the polarity of the input voltage.Double coil, that is, two coils, one coil control disconnect, the other coil control close.For example, the single-coil circuit, due to its control circuit needs a voltage polarity conversion, the general use of the simple circuit is H bridge (H bridge, often used to control the positive and negative motor rotation), there is also the use of magnetic holding relay special control chip, its internal structure is also H bridge, but it has added some amplification and protection circuit.
To sum up, Magnetic latching relay has the advantages of fast action, stable performance, long service life, small volume, etc., and is widely used in intelligent electricity meters, charging piles, intelligent lighting, intelligent distribution network and other occasions.
