Is it correct to choose aR or gR for automotive fuses?

1. Fuses are classified into working levels according to their functions,

The first letter represents the functional level, and the second letter represents the object to be protected.

1. Initial letter

A – Local range protection (backup protection fuse)
G – Comprehensive protection (universal fuse)

2. Second letter

G – Cable and Wire Protection (General)
M – Switchgear 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 of semiconductor protection

3、 In addition, the fuse is also labeled with “slow action” and “fast action”, which are specified by IEC/CEE/DIN VDE standards.

DIN is the German standard code, VDE stands for “German Institute of Electrical Engineers”, which can publish its own
Safety standards. IEC stands for International Electrotechnical Commission. ）

1. Quick action: When short circuited, the disconnection speed is faster than gL/gG.
Suitable for high-speed disconnection.
2. Slow motion: Suitable for DC railway power systems and high inductance DC currents.
Both types are suitable for protecting cables and wires.
The full range of fuses (gL/gG, gR) can provide overload and short circuit protection.
The local series fuses (aM, aR) only provide short-circuit protection.

3. Letter introduction:

GL (DIN VDE)/gG (IEC): Comprehensive Cable and Wire Protection
AM (DIN VDE/IEC): Partial range motor circuit protection
AR (DIN VDE/IEC): Partial range semiconductor protection
GR (DIN VDE/IEC): Full range semiconductor protection