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How do you calculate fuse rating?
The fuse rating can be calculated by dividing the power used by the appliance by the voltage going into the appliance. I (Amps) = P (Watts) ÷ V (Voltage).
How do you determine the rating of an induction motor fuse?
Motor Fuse sizing calculation:
- For single-phase: Motor fuse rating = PkW x 1.25 / (pf x V(V))
- For Three-phase: Motor fuse rating = PkW x 1250 / (1.732 x power factor x V(V-L))
- Fuse rating Calculation:
- For single-phase:
- For Three-phase transformer,
- Example:
How would you choose the correct fuse to fit for an electrical appliance?
Selecting the correct fuse
- Fuses come in various ratings, but the common sizes are 3 A, 5 A and 13 A.
- The current flowing through an appliance can be calculated using the equation:
- Electric power P = voltage V x current I.
- P = VI.
- Once the current is known the next highest fuse rating is chosen.
What is the current rating of a fuse?
Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element. A wide range of power switching transistors are also available, with current rating up to several hundred amperes and voltage ratings well over 1000V.
What are motor rated fuses?
Motor circuit protection fuse-links have a dual current rating, consisting of a continuous current rating and a rating relating to the operational characteristics. The letter ‘M’ separates these two ratings, for example, 20M32.
How does the fuse rating differ from the rating of electrical device?
More the Power of the device more the fuse rating.. so since current will be more, the fuse rating will be higher.
What is the fuse rating?
The maximum value of safe current allowed to flow through a fuse wire before it melts is called fuse rating. If a fuse of higher rating is used, it will not blow and protection of the circuit will be achieved. If a fuse of lower rating is used, it will blow before the circuit is fully loaded.
What is current fuse rating?
How to calculate fuse rating for electrical equipment?
The function of a fuse is to break a circuit when a current threshold is exceeded. It’s a single function device, and historically single-use. Calculating the rating of very basic protection equipment fuse, we use the thump rule just select a fuse rated 150% – 200% of normal operating current of the specific circuit.
How do you choose the correct fuse size?
Identify the smallest gauge wire the load current will flow through. One common misconception about choosing the correct fuse size is that it depends on the load of the circuit. However, the load of the circuit is not suitable to use alone when choosing a fuse size. The fuse size should be based on the SMALLEST wire in the circuit.
How to calculate fuse sizing for a 250kVa transformer?
Calculate the fuse sizing of the 250kVA, 415 V three-phase transformer. Hence the nearest available size of the fuse is 710Amps. Therefore, 250kVA transformer can be charged with the 710A fuse. For the lighting circuit, the fuse current rating should be minimum 2 times the full load current of the total number of lighting.
How to calculate fuse rating for three phase transformer?
For Three-phase transformer, Transformer fuse rating = 2000 x S (kVA) / (1.732 x V (V-L)) Example: Calculate the fuse sizing of the 250kVA, 415 V three-phase transformer. Fuse rating = 2000 x 250 / 1.732 x 415 = 696 Amps. Hence the nearest available size of the fuse is 710Amps. Therefore, 250kVA transformer can be charged with the 710A fuse.