Application Notes Relays - zettlerelectronics（应用笔记继电器zettlerelectronics）.pdf

Application Notes Relays Electromechanical Relays A member of the ZETTLER Group www.ZETTLER Defi nitions and Application Notes Air distance Switching high loads creates arcs; these arcs may not extinguish ➝ Clearance before the movable contact of a ➝ change-over relay touches the opposite contact. The intrinsically insulated outer contacts All-or-nothing relay are then connected by the arc; this leads to short circuits (e.g. Electrical relay whose ➝ input energizing quantity is either within in the applications shown below). This problem can be avoided the operative range or zero; ➝ wave form of coil energization. by using a separate relay which interrupts the circuit before the change-over relay switches and which closes the circuit Ambient temperature (in use) afterwards. Temperature, measured directly near the relay. The maximum allowed value may not be exceeded, otherwise there is the danger of lasting damage (e.g. reduced contact force or over- heating of the energized coil). Ambient temperature (storage and transport) The maximum allowed value may not be exceeded, otherwise there is the danger of lasting damage. Application guidelines Very diff erent loads (e.g. high load and measuring signal) shall not be switched by the same relay. ➝ Contact erosion from switching high loads may pollute the low level switching contacts. The actual contact load shall not be lowe