5MFP 8-R vs 5MFP 3-R
| Part Number |
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| Category | Fuses | Fuses |
| Manufacturer | Bel Fuse Inc. | Bel Fuse Inc. |
| Description | FUSE GLASS 8A 125VAC 5X20MM | FUSE GLASS 3A 250VAC 5X20MM |
| Package | 5mm x 20mm (Axial) | 5mm x 20mm (Axial) |
| Series | 5MFP | 5MFP |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
| Mounting Type | Through Hole | Through Hole |
| Package / Case | 5mm x 20mm (Axial) | 5mm x 20mm (Axial) |
| Size / Dimension | 0.217" Dia x 0.827" L (5.50mm x 21.00mm) | 0.217" Dia x 0.827" L (5.50mm x 21.00mm) |
| Current Rating | 8A | 3A |
| Fuse Type | Cartridge, Glass | Cartridge, Glass |
| Voltage Rating - AC | 125V | 250V |
| Breaking Capacity @ Rated Voltage | 10kA | 200A |
| Response Time | Fast | Fast |
| Approvals | CE, CSA, PSE | CE, CSA, cULus, PSE |
| Melting I²t | 113 | 13 |
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1. What are fuses used for?
The main uses of fuses include the following aspects:
Overload protection: Fuses play an overload protection role in circuits. When the current in the circuit exceeds the rated current of the fuse, the fuse will automatically melt and cut off the circuit, thereby preventing the circuit from being damaged due to overload. This protection mechanism is very important for preventing equipment damage and fire accidents.
Short circuit protection: When an abnormal situation such as a short circuit occurs in the circuit, the current will increase sharply, and the fuse will quickly melt and cut off the power supply, thereby preventing the circuit and equipment from being damaged by excessive current. This protection measure can effectively prevent the precision components inside the equipment from being irreversibly damaged.
Adjusting current: The rated current value of the fuse can be adjusted and set according to the power size of the equipment. When the current in the circuit is too high, the fuse will automatically melt, thereby reducing the current and protecting the equipment from overload. This feature makes the fuse a convenient current controller.
Preventing fire and safety accidents: When the current is too high, the circuit may generate high temperature and even cause a fire. Fuses cut off the current by melting, effectively preventing fires or other safety accidents caused by excessive current.
Ensure user safety: In the case of unstable external power supply or improper operation, the fuse can quickly cut off the circuit to avoid electric shock or other personal safety accidents caused by abnormal current. -
2. What is this fuse?
A fuse is a component used for circuit protection, also known as a fuse or fuse. Its main function is to automatically melt and cut off the current when the current abnormally rises to a certain height and temperature, thereby protecting the safe operation of the circuit.
Definition and function of fuse
Fuse is defined as a fuse according to IEC127 standard, and its main functions include:
Overload protection: prevent the current from exceeding the rated current of the equipment or circuit, avoiding equipment damage or fire.
Short circuit protection: when a short circuit occurs in the circuit, quickly cut off the circuit to prevent the short circuit current from spreading further.
Personnel safety: ensure the normal operation of the equipment and avoid the risk of electric shock caused by short circuit of electrical contacts or current overload.
Equipment protection: reduce the cost of repair and replacement of electrical equipment and protect the entire electrical equipment system. -
3. Is the fuse AC or DC?
Alternating current
Fuses can be used for both AC and DC. The design and application of fuses depend on their specific type and purpose.
Application of fuses in AC and DC
AC fuses: suitable for AC circuits, using the current zero-crossing characteristics to extinguish arcs, commonly found in household appliances and industrial equipment. The frequency of AC (such as 60Hz or 50Hz) makes it easier to extinguish arcs, so the size of AC fuses is relatively small.
DC fuse: Designed for DC circuits. Since DC has no zero point, it is more difficult to break the arc. Usually, special structures (such as filling with quartz sand) are required to force the arc to extinguish. DC fuses are usually larger in size to reduce arcing. -
4. What is the main function of a fuse?
Overload protection
The main function of a fuse is overload protection. After the fuse is properly placed in the circuit, when the current abnormally rises to a certain height and temperature, the fuse will melt itself to cut off the current, thereby protecting the safe operation of the circuit. The working principle of the fuse is based on the fact that heat is generated when current flows through a conductor. When the heat generated exceeds the speed at which the conductor dissipates heat, the fuse will melt.
