1. Fuses are classified into working levels according to their functions. At this time, the first letter indicates the functional level, and the second letter indicates the object to be protected.
1. First letter
a Local range protection (backup protection fuse)
g Full range protection (general purpose fuse)
2. Second letter
G Cable and wire protection (general application)
M Switching device protection (motor circuit protection)
R Semiconductor protection (used as rectifier protection)
L Cable and wire protection (according to DIN VDE regulations)
II. 1. Fuse aR (DIN VDE/IEC) Local range semiconductor protection
2. Fuse gR (DIN VDE/IEC) Full range semiconductor protection
III. In addition, "slow action" and "fast action" are also marked on the fuse, which is stipulated in IEC/CEE/DIN VDE (DIN is the code of German standard, similar to the "GB" in front of the Chinese standard number; VDE is the world's authoritative certification body, (abbreviation of "German Electrical Engineers Association") They can publish their own safety standards, and the standards they publish are often adopted as German standards. "VDE DIN" placed before the German standard means that this standard is a German standard published by VDE. IEC is the International Electrotechnical Commission).
1. The "fast action" characteristic means that the fuse disconnects faster than the working level gL/gG under short-circuit conditions. The fuse used in the DC-railway power supply system has a "slow action" characteristic, which is particularly suitable for breaking DC currents with large inductance.
2. The fast action and slow action characteristics of the fuse are also suitable for protecting cables and wires. Full range fuses (gL/gG, gR, fast action, slow action) can safely and reliably disconnect overload currents and short-circuit currents. Local range fuses can only be used for short-circuit protection (aM, aR).
3. Letter introduction:
gL (DIN VDE)/gG (IEC) Full range of cable and wire protection
aM (DIN VDE/IEC) Partial range of motor circuit protection
aR (DIN VDE/IEC) Partial range of semiconductor protection
gR (DIN VDE/IEC) Full range of semiconductor protection