One is to screen the main failure environmental factors by simulating the actual use environment (such as temperature, air pressure, humidity, salt spray, impact, vibration, external use current conditions, especially the charge-discharge curve impact). Another is to analyze and verify the composition of the key component materials such as contact materials, contact point design area and shell materials, consider the principle characteristics of the material factor from the intrinsic perspective, and combine these data to analyze the failure rate of after-sale data. In fact, there are external disturbance factors: including the different arc bin structure of the contactor, the structure of the drive coil (now the two-stage coil structure) and the drive control mode, the difference of the external drive circuit, some energy-saving drive circuit.
These are what we do research and accumulate data, and then accumulate.
Anyway, the main difference between the contactor and the relay lies in the disconnected load situation
Contactors are used for a load type with high voltage, high current or both. Generally used for equipment with more than 15 amps or 3kW. For lower quantities, a common relay is used.
Note: in fact, we use the contactor and relay is also to see their own hobbies, you do not believe to see how the Japanese use: the preface is written so, this series is not contactor?
From the domestic design mainly has these differences, we are rigorous point or to distinguish below
1) Differdifference in current driven by contact
Generally, the manufacturer will give a factory value of the conduction resistance, and we will evaluate the long-term heating model of the whole contact according to this value. This point also needs us to discuss carefully, what is the actual temperature of the contact? Does the contact affect the heating of the warehouse, especially the external seal structure? The actual contact size, material, and contact situation will have a large impact on the following similar absolute characteristics.
When we actually take apart the contactor, the contacts are not small. Although some contactors are separated by different current and different contact sizes, we need to establish a real database in this place, to select samples for coil aging = contact resistance monitoring and contact temperature monitoring
Contactor carrier
Relay carrier
This heat, mainly or the above bolted connection impedance and static contact connection impedance two parts of heat.
2) The contactor is equipped with an arc suppression mechanism, but the relay usually does not have it
At very high power loads, currents are likely to cross contact points when the switch is converted. Electric shock may cause significant damage to the contact point, causing the contact point failure earlier than its expected life. At at lower voltage with relarelay. This basic specificity determines the difference in the characteristics of the break:
Figure 1. The properties of the contact material are very critical
The fragmentation diagram, and the safety analysis of emergency electric vehicle power system, we on the one hand in the separation of consideration, need to directly record and consider the vehicle safety in which state really want to do so, such as collision, such as voltage drop, temperature rose sharply, unable to output power such as thermal runaway conditions.
3) The difference between the contactor and the relay is the power consumed in the maintenance conduction state
The contactor requires the design of the actuator to switch larger contacts, thus requiring a much larger solenoid coil, which consumes more current during startup and maintenance. In contrast, the smaller electromagnet in the relay is easier to switch and does not require much current.
Post time: May-05-2023
