1. Loose or cracked contacts
Contacts are the electrical contact parts that complete the switching of loads in relays. Some products have contacts that are riveted or press-fitted, and the main defects are loose contacts, cracked contacts, or excessive deviation in size or position. This will affect the contact reliability of the relay. The occurrence of loose contacts is caused by unreasonable dimensions in the matching parts of the spring and contact, or improper adjustment of the riveting pressure by the operator. Contact cracking is caused by excessive material hardness or excessive pressure.Three-phase clamp phase volt-ampere meter can directly display vector diagrams, especially suitable for power supply and consumption units to check the wiring status of electric energy metering systems and relay protection systems. For contacts of different materials, different material processes are adopted. Some contact materials with higher hardness should be annealed before contact manufacturing, riveting, or spot welding. Contact manufacturing should be done carefully because there are tolerances in materials, so the cutting length should be determined after trial cutting each time. Contact manufacturing should not have burrs, scratches, or incompleteness. Contact riveting deviation is caused by the operator not aligning the mold correctly or misalignment of the upper and lower molds. Contact damage and contamination are caused by not cleaning oil stains and iron filings on the mold. No matter what kind of defect, it will affect the working reliability of the relay. Therefore, during the contact manufacturing, riveting, or welding process, it is necessary to comply with the self-inspection regulations of first-piece inspection, middle sampling, and final inspection to improve assembly quality.
2. Unstable relay parameters
Many parts of electromagnetic relays are riveted, and the main problem is loose riveting or poor bonding strength. This defect can cause unstable relay parameters, large parameter changes under high and low temperatures, and poor resistance to mechanical vibration and impact. The main reasons for this problem are oversized riveted parts, improper placement of parts, unqualified molds or incorrect installation. Therefore, before riveting and welding, it is necessary to carefully inspect the molds and riveted parts to ensure they meet the requirements.
3. Deformation of electromagnetic system riveted parts
After riveting, parts may bend, twist, or become upset, causing difficulties in assembly or adjustment in subsequent processes, and may even lead to scrapping. The main reasons for this problem are oversized or undersized riveted parts, uneven force during riveting, mold assembly deviation or design size errors, and improper placement of parts. During riveting, operators should first check whether the dimensions, appearance, and molds of the parts are correct. If the mold is not installed in place, it will affect the assembly quality of the electromagnetic system or cause core deformation or upsetting.
4. Damage to glass insulators
Glass insulators are made by sintering metal pins and glass. During inspection, assembly, adjustment, transportation, and cleaning, it is easy to cause bending of pins, chipping or cracking of glass insulators, resulting in air leakage and reduced insulation and withstand voltage performance. Pin rotation can also cause displacement of contact springs, affecting reliable on-off of the product. This requires assembly operators to handle parts gently throughout the relay production process, arrange parts neatly in transfer boxes, and not bend or twist the lead-out pins during assembly or adjustment.
5. Coil faults
There are many types of coils used in relays, some with outer wrapping and some without. Coils should be stored separately in special containers to avoid collision and entanglement, which can cause wire breakage when separated. During riveting of the electromagnetic system, the pressure of the hand press or press machine should be adjusted appropriately. Excessive pressure can cause coil wire breakage, coil frame cracking, deformation, or winding breakdown. Too little pressure can cause loose winding and increased magnetic loss. Multi-winding coils usually have leads of different colors as heads. When soldering, care should be taken to distinguish them, otherwise the coil may be soldered incorrectly. Coils with start and end requirements are usually marked to indicate the start and end. During assembly and soldering, attention should be paid to avoid reverse polarity of the relay.
