Hecheng Electric DC Relay Design Features
Design to improve short-circuit resistance
- Why need to resist the external force when electrified:
- 1. The ampere force of a energized conductor in a magnetic field (Figure ①):
- According to the left-hand rule, the magnetic field generated when energized will cause the contact bridge to receive a relatively downward force;
- 2. Electric contraction force generated by contact energization (Figure ②):
- The microscopic contact surface is not smooth, and the current line shrinks through the contact surface, which causes an electric repulsion between the contacts to prevent the contacts from closing.
- When a short-circuit current or a large current occurs, the above forces have a huge impact on the contact bridge, and even directly cause the contacts to separate and generate an arc, which affects safety.
- How to resist the external force when electrified:
- Principle: Placing an armature fixed relative to the contact bridge at a suitable position above the contact bridge, and the other armature is bound to the contact bridge. The magnetic field generated by the energization magnetizes the two armatures to form a magnetic circuit, and then attracts each other to force the contact bridge upward.
- The effect achieved by this design:
- This design overcomes the limited space in the ceramic arc extinguishing cavity, Reasonably achieved the compensating force mechanism, and can be used in contactors above 100A;
- This design can ensure that the contacts are reliably closed and not separated when passing a current of 8kA, which improves the short-circuit resistance of the product.
Design Of Square Ceramic Auxiliary Switch
Reasons for setting auxiliary switches ：
- The auxiliary switch is a monitoring mechanism synchronized with the on-off state of the main contact, which load is small and main function is signal feedback.
- Many applications need to monitor the working status of the contactor at present, such as whether it is in the disconnected state or whether it can be turned on and off normally etc.
Design of auxiliary switch：
- Through some transmission mechanism or signal transmission to reach the auxiliary switch, then gets the feedback of the working status of the main loop.
Difficulties in the design of auxiliary switches：
- Ceramic interior space is limited.
- Ensure the performance of electrical life and temperature rise.
- Special structure design.
Effect of auxiliary switch：
- Overcoming the limited space problem, being applied in products above 100A.
- Accurately and reliably monitor the working status of the main contact, and the parameters and status still meet the requirements.
Product application platform:
- The design of the entire series of products is based on the 1000V voltage platform requirements.
- 400A series products meet the requirements of 1500V voltage platform, being used in super charging, photovoltaic, energy storage and other application scenarios.
- Ceramic sealing structure.
- The cavity is filled with hydrogen gas mixture to prevent oxidation of the contacts. And the gas leakage rate is less than or equal to 6.0*e-9Pa.m3/s, and long service life to meet the vehicle quality assurance requirements.
- Non-polar arc extinguishing design, whish is suitable for the two-way current scenario of the loop, and uses ceramic seals to achieve zero flashover, ensuring safety and reliability.
Hecheng Electric Design Features of Smart Electrical Air-conditioning Contactors
SA&HCDP Summary of technical highlights
Product action reliability design
Reliable pull-in at 70%~110%Us, carrying line voltage fluctuation；
The influence of voltage fluctuation:
Considering line voltage fluctuation is an inevitable phenomenon in most application scenarios, short-term pressure loss will cause the contactor to malfunction and affect the operation of the equipment; Frequent pressure loss will cause frequent contactor release, affecting product life and equipment life.
Method to realize：
Matching calculation of suction force and reaction force curve to ensure reliable suction.
Reasonable iron core and magnetic split ring, no vibration after 75% Us is attracted；
The influence of vibration:
Affect product life and temperature rise;
Method to realize:
Through the optimized design of the short-circuit ring to ensure sufficient retention.
Summary of SA&HCDP Technical Highlights
Design of Product Reliability
Coil protective cover design to better protect the iron core;
Damage of Unprotected：
Most of the application scenarios are dusty and the iron core is not protected, which will cause the iron core area to be gray, then affect the product performance;
Silver contact point protection treatment ensures long-term low contact resistance and connection reliability;
Influence of Unprotected：
Silver contact point are easy to vulcanize, which affects product contact resistance; no power after action;
Method to realize：
Increasing the cleaning of silver contact point and the high-temperature protection treatment process, extending the vulcanization cycle of silver contact point to make the contact resistance change slowly;
AgCdO2 silver contact point, and the uniform thickness of the silver layer ensure the electrical life;
Design of Product Practicality
Full series of standard quick-connect terminals； In addition to the quick-connect terminal, there are two options for Screw connection method, and being arbitrarily matched;
The bottom plate is installed with a porous design, and the installation size can be freely selected;
3P&4P accessory auxiliary contact point has multiple combinations choice , and there are micro switch types to ensure low current reliability;