How do you calculate motor fuse rating?
Formula to Calculate the Fuse Rating
V for voltage in volt); I for current in Amps. 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).
What is rating of a fuse?
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 type of fuse is best for motor protection?
Time delay fuses
How many watts can a 5 amp fuse take?
Fuse ratings45 AMPFor circuits of more than 13kw (13000 w)13 AMPFor appliances between 700 and 3000w (3kw)5 AMPFor lighting circuits. The maximum permissible load of a lighting circuit is 1200w or 12* 100 watt lamps3 AMPFor appliances up to 700 watts, such as table lamps and alarm clocks3
How do you size a 12v fuse?
- Find the continuous amperage of the device you are trying to power and multiply that number by 1.5, then round up to the nearest fuse size you can find.
- Cross check that fuse size with the maximum fuse size chart below and verify that your fuse size is below the maximum fuse size listed in the chart.
How many amps is 3 horsepower?
Common Horsepower to Amps ConversionsHorsepowerAmpsVoltage3 HP20.7 A120 V3.5 HP24.2 A120 V4 HP27.6 A120 V4.5 HP31.1 A120 V11
What is full load current of a 3 phase motor?
All are given at the nameplate details. Look at the above formula, the three-phase full load current is equal to Power divided by the 3 times of product of line to neutral voltage and power factor. Here three-phase full load current is equal to the power divided by 1.732 times of line to line voltage and power factor.
How many amps does a 1.5 HP 3 phase motor draw?
AC Motor Full Load AmperesHP200 Volts380-415 Volts1/22.51.33/43.71.8220.127.116.11.93.323
How do you create a fuse rating?
In order to select the right amperage of the fuse, you first need to know the full-load steady-state current of the circuit at an ambient temperature of 25º C (68º F). Once the current value is determined, then a fuse rating should be selected as to be 135% of this value (taken to the next standard value).
What is Max series fuse rating?
The module manufacturer also lists the maximum series fuse rating. This value dictates the largest size OCPD that can be used — typically modules have 15A or 20A series fuse ratings. … Therefore, if three strings are placed in parallel, the output circuit OCPD’s rating would be calculated as: 32.7A × 1.25 = 40.8A.
What is minimum fuse rating?
For the lighting circuit, the fuse current rating should be minimum 2 times the full load current of the total number of lighting. For individual circuit, the fuse rating should be 1.5 times of the full load current.
Why is it better to use a circuit breaker than a fuse?
The breaking capacity of a circuit breaker can be greater than equivalent fuses (up to 150 kA). And under overload conditions, a circuit breaker can trip up to 1000 times faster than a fuse. Some circuit breakers also provide exceptional fault current limitation, a capability previously associated only with fuses.
What should motor overloads be set at?
2) Thermal Overload Set Incorrectly-The basic requirement for overload protection setting for motors is 125% of their full-load current according to the NEC; however, it makes sure you read the overload relay instructions.
Do all motors need overload protection?
Most other continuous duty motors having a marked service factor of not less than 1.15 or, with a marked temperature rise not over 40 degrees Celsius, are required to have overload protection rated at 125 percent of the motor nameplate full-load current rating.