Selection outline before selecting the relay
In order to reduce the randomness of relay selection and improve autonomy, a selection outline should be written before selection, which generally includes the following elements:
(1) Elements of Climate elements
Temperature range: humidity range; atmospheric pressure; coastal atmosphere; sand and dust pollution; chemical pollution; magnetic interference; other special climatic stress.
(2) Elements of mechanical elements
Vibration stress; impact stress; centrifugal effect and others.
(3) Input parameter elements
AC parametric excitation; DC parametric excitation; effect of temperature change; excitation mode with or without contact; solid-state switch excitation mode; long-distance wired excitation mode; mutual interference and other excitation factors; low-voltage excitation and high-voltage (high-voltage circuit) output isolation Factors.
(4) Output parameter elements
Incandescent lamp; capacitive load; motor load; inductor, solenoid, contactor coil, choke load; DC resistive load; medium current load; low-level load; dry circuit load, etc. .
(5) Installation method requirements
Welding, plug-in, screw-type or other (such as rail-type installation, etc.)
(6) Security elements
Flame retardant requirements; overload capacity requirements; insulation resistance level.
(7) Screening requirements
The screening requirements include the items to be screened, the applied stress, the monitoring level, monitoring methods, and failure criteria.
(8) Failure rate requirements and reliability assessment
Failure criterion; failure rate assessment and confidence.