Motor choice, what does "max amps" really mean?
01-25-2017 | 06:38 PM
#1
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Joined: Jan 2010
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From: NY/NJ
Motor choice, what does "max amps" really mean?
So I'm not a huge newbie to the electric scene, but was wondering what this spec. on motors means. Does "Max amp" mean that is this max it will pull, or the max it will tolerate before some kind of failure? I've attached a screenshot for reference. Can't any motor pull any amount of amps depending on load? Help electric experts 
01-25-2017 | 09:28 PM
#2
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RC Brushless Motor Ratings – Current Rating / Amps
The max current rating refers to the maximum amount of current that a motor is able to handle safely. This current is measured in Amps. The continuous current rating of a motor is the Amps that a motor can handle safely over a long period of time.
You can normally find the estimated current rating of a motor on the factory specs sheet. However the actual current that a Brushless motor will draw depends on a few factors, Kv rating, voltage of batteries, weight of RC vehicle, and gear ratio or prop size.
These all come into play because the harder that a motor needs to work in order to reach its Max RPM/top speed the higher the Amp draw will be. This is why it is a great idea to find an ESC that has a current rating that is higher than your motor’s by at least 20%. It will be a good safety cushion to make sure that you don’t burn up your brushless power plant.
The max current rating refers to the maximum amount of current that a motor is able to handle safely. This current is measured in Amps. The continuous current rating of a motor is the Amps that a motor can handle safely over a long period of time.
You can normally find the estimated current rating of a motor on the factory specs sheet. However the actual current that a Brushless motor will draw depends on a few factors, Kv rating, voltage of batteries, weight of RC vehicle, and gear ratio or prop size.
These all come into play because the harder that a motor needs to work in order to reach its Max RPM/top speed the higher the Amp draw will be. This is why it is a great idea to find an ESC that has a current rating that is higher than your motor’s by at least 20%. It will be a good safety cushion to make sure that you don’t burn up your brushless power plant.
01-26-2017 | 04:52 AM
#3
Thread Starter
Tech Adept
Joined: Jan 2010
Posts: 134
From: NY/NJ
Thanks for the info!
So the max rated current on the info sheet it the max the motor SHOULD pull to keep it safe, not necessarily what it's actually going to pull given the current conditions. Which can be higher or lower.
In the case of a high load condition such as speed runs, would a "bigger" motor rated for higher amperage (let's use 400a for example) be actually pulling lower amps because it doesn't need to work as hard as say a motor rated for 100a?
The question then becomes is it better to use a smaller motor with a lesser rated amperage so that it doesn't murder the ESC or a bigger motor with a higher rated amperage so it doesn't "work as hard" thus also no murdering the ESC? and also not nearing the motors max amp limit?
So the max rated current on the info sheet it the max the motor SHOULD pull to keep it safe, not necessarily what it's actually going to pull given the current conditions. Which can be higher or lower.
In the case of a high load condition such as speed runs, would a "bigger" motor rated for higher amperage (let's use 400a for example) be actually pulling lower amps because it doesn't need to work as hard as say a motor rated for 100a?
The question then becomes is it better to use a smaller motor with a lesser rated amperage so that it doesn't murder the ESC or a bigger motor with a higher rated amperage so it doesn't "work as hard" thus also no murdering the ESC? and also not nearing the motors max amp limit?
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