# How many amps does a motor need?

Contents

## How many amps does a 1.5 hp motor use?

Common Horsepower to Amps Conversions

Horsepower Amps Efficiency
.75 HP 5.18 A 90%
1 HP 6.91 A 90%
1.25 HP 8.63 A 90%
1.5 HP 10.4 A 90%

## How much power is needed to run a motor?

Most electric motors are designed to run at 50% to 100% of rated load. Maximum efficiency is usually near 75% of rated load. Thus, a 10-horsepower (hp) motor has an acceptable load range of 5 to 10 hp; peak efficiency is at 7.5 hp. A motor’s efficiency tends to decrease dramatically below about 50% load.

## How powerful is a 15 amp motor?

Others are rated 15 amp and are rated 3 or 3 1/2 HP, Porter Cable and Milwaukee. On an induction motor which is brushless, unlike a router, a 12 amp rating is generally 3/4 HP, a 15 amp rating is generally 1 HP. 746 watts = 1 hp. at 120 volts that is about 6.25 amps per hp.

## How much current is needed for a 5hp motor?

Full-Load Current in Amperes Single-Phase Alternating Current Motors

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HP 115V 230V
5 56 28
7-1/2 80 40
10 100 50
The voltages listed are rated motor voltages. The listed currents are for system voltage ranges of 110 to 120 and 220 to 240.

## How many HP is 15 amps?

Common Amps to Horsepower Conversions

Amps Horsepower Efficiency
15 A 2.17 HP 90%
20 A 2.9 HP 90%
25 A 3.62 HP 90%
30 A 4.34 HP 90%

## How many amps does a 25 hp motor draw?

AMP DRAW BASED ON HORSEPOWER

HP 1 Phase Amps 3 Phase Amps
115 volt 208 volt
15 46.2
20 59.4
25 74.8

## How do I know what size motor breaker I need?

You must size the conductors at 125% of the motor FLC [430.22(A)]. You must size the overloads no more than 115% to 125% of the motor nameplate current rating, depending on the conditions [430.32(A)(1)].

## How do you find the amperage of a motor?

Given horsepower and volts, it is possible to calculate amps. The calculation of amps uses Ohm’s Law, which is amps times volts equals watts. Multiply the horsepower by 746 watts. For example, an engine at two horsepower with 230 volts would be calculated as two horsepower times 746 watts, which equals 1492.

## How much power does a 20 hp motor use?

If the motor actually delivers 20 horsepower (hp) of mechanical power, then the motor will draw 49 amps.

## What size breaker do I need for a 15 amp motor?

A 12 wire and a 20A breaker is needed. 15A ends can be used on 20A circuits.

## Will a 15 amp saw trip a 15 amp breaker?

To the right of the grey band: definitely will trip, above magnetic trip. You can check the stall current by measuring the resistance of the motor, and calculate I = 120/R. It’s usually not listed, and likely well above the 15A rating. Your breaker will not trigger immediately if the current is briefly above 15A.

## How many volts are in a horsepower?

1 horsepower ≈ 745.7 volt-ampere.