Slow blow fuse and how to distinguish the power of the fuse
May 31, 2022
How to distinguish the power of the fuse? What is a slow low fuse? What is its working principle? The following is an analysis by the car fuse holder manufacturer.
1. What is a slow fuse
The deceleration fuse is also called a delay fuse. Its delay characteristic is as follows: when a non-fault pulse current occurs in the circuit, it is not affected by the interference current and provides protection against overload. The current of some circuits is several times larger than the normal current when switching instantaneously. Although this peak value is very large, it appears for a very short time. We call it pulse current, and some call it impulse current, or surge. current. Ordinary fuses cannot withstand this kind of current. If such circuits are used with ordinary fuses, they may not be able to start normally. If larger fuses are used, the circuit cannot be protected when overloaded. The melt of the delay fuse is specially processed to absorb energy. Adjusting the energy absorption can make it resistant to inrush current and protect overload. The specification specifies the characteristics of delay. If the characteristics specified in the standard cannot meet your requirements, you can contact the manufacturer to solve it.
Second, how to distinguish the power size of the fuse
The fusing current of the fuse should be between the rated current and the maximum current of the equipment, so as to ensure the normal operation of the equipment. Timely power off when approaching maximum current
The rated current is the current of the electrical appliance working at the rated voltage, which refers to the maximum current that is allowed to pass for a long time when the heat generation does not exceed the allowable temperature for long-term heat generation at the reference ambient temperature and under the working conditions of the rated voltage.
The maximum current refers to the limit of the current that can be withstood without affecting the safe state of the equipment. Generally, it is only allowed to appear for a short time, otherwise the equipment will be damaged.
The maximum working current of the motor is its working current, which can work for a long time, generally up to 1.2 times of the rated current. Usually, the motor selection is too small due to improper calculation of the design power, but when the rated power exceeds the rated power, the motor can continue to work. The current is the maximum working current.
In general, when selecting a fuse, its fusing current should be considered. For example, a 30A fuse means that its blowing current is 30A, that is, when the current in the circuit reaches 30A, the fuse will blow. However, when the load power increases, the current increases. Therefore, it also indirectly reflects the power size. According to the estimation of the 380V voltage squirrel cage motor, the rated current of the 50KW motor is about 50A, and the rated starting current is 50×6=300A. The calculation formula for selecting the fuse is Inf=Ie/(1.8～2.5 )=300/2=150A.
The above is the introduction of "how to distinguish slow-melting and fast-melting fuse sockets". For more detailed information about fuse sockets, please contact our manufacturer.