# Frequent question: What is the fuse rate for a 3 HP 3 phase induction motor at full load?

Contents

## How do you find the fuse rating on a 3 phase motor?

Motor Fuse sizing calculation:

1. For single-phase: Motor fuse rating = PkW x 1.25 / (pf x V(V)) …
2. For Three-phase: Motor fuse rating = PkW x 1250 / (1.732 x power factor x V(V-L)) …
3. Fuse rating Calculation: …
4. For single-phase: …
5. For Three-phase transformer, …
6. Example:

## How do you calculate full load amps on a 3 phase motor?

The motor FLA calculator uses the following formulas:

1. Single Phase AC Motor FLA (Amperes) = (P [kW] × 1000) / (V × cos ϕ)
2. Single Phase AC Motor FLA (Amperes) = (P [HP] × 746) / (V × cos ϕ × η)
3. Three Phase AC Motor FLA (Amperes) = (P [kW] × 1000) / (V × 1.732 × cos ϕ)

## What is the fuse rate for a 10 HP 3 phase induction motor at full load?

10 HP motor is invariably 3 phase motor, and in India, rated for 440 V. Current at full load will be 13.1 Amp. Fuse rating will be more than double of this to account for starting currents, and correct rating will be 30 Amps for wired fuses.

## What size breaker do I need for a 3 HP motor?

Full Load Current: Three Phase AC Motors

Motor Horsepower Size Breaker
1 230V 460 V 15 15
1-1/2 230V 460V 15 15
2 230V 460V 15 15
3 230V 460V 15 15

## What type of fuse is best for motor protection?

Time delay fuses are the most useful fuses for motor branch circuit application. A time delay fuse can be sized closer to motor full load current, providing a degree of overload protection, better short circuit protection, and possible use of a smaller disconnect switch.

## What is the phase displacement between windings in 3 phase motor?

Phase displacement is 120˚ between each phase.

## How many amps is 3 horsepower?

Common Horsepower to Amps Conversions

Horsepower Amps Voltage
3 HP 20.7 A 120 V
3.5 HP 24.2 A 120 V
4 HP 27.6 A 120 V
4.5 HP 31.1 A 120 V

## How do you calculate the starting current of a 3 phase motor?

An induction motor, starting “across the line”, will typically have an instantaneous draw 6x the kw it is rated to run at. e.g. a 10 hp motor is rated at 7.46 kw, so on starting it may draw 75 kw. On 480 volts 3 phase, the amperage will be I = W / (E x 1.73) = 75,000 / (480 x 1.73) = 90.4 amps.

## How many amps does a 3 phase 10 hp motor use?

AMP DRAW BASED ON HORSEPOWER

HP 1 Phase Amps 3 Phase Amps
115 volt 208 volt
10 100 30.8
15 46.2
20 59.4

## What is the fuse rating that can be selected for a 5 HP induction motor?

Womack Data Sheet 78: Wire Size and Fuse Ratings for 3-Phase Induction Motors

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HP Speed RPM 230-Volt Service
5 1,200 30
5 1,800 30
5 3,600 30
7-1/2 1,200 40

## How do you select a motor overload relay?

2. Min. Thermal Overload Relay setting = 70%x4 = 3 Amp.
4. Max. Thermal Overload Relay setting = 120%x4 = 4 Amp.

11.09.2013

## How is motor overload setting calculated?

The overloads are determined using 125% of the FLA, 7A x 1.25 = 8.75A. The maximum allowable size for the overloads is 9.8A. The overloads can be sized at 140% of the FLA if the overloads trip at rated load or will not allow the motor to start, 7A x 1.4 = 9.8A.

## How many amps is a 3hp 220v motor?

HP 200 Volts 220-240 Volts
3 11 9.6
5 17.5 15.2
7.5 25.3 22
10 32.2 28

## Can I use 12 gauge wire on a 30 amp breaker?

No. 12 gauge wire is rated for a maximum of 20 amps. You need a minimum of 10AWG wire for 30 amps. … Electrical current is measured in amperage (amps), and each wire gauge has a maximum safe carrying capacity.