# Maximum Continuous Current in BLDC motor.

#### Track99

Joined Jun 30, 2022
38
Hello my friends. The datasheet for the BLDC motor below is saying that the "Maximum Continuous Current" is 21 A (205 s).

1) Does this mean, in normal english, that the motor can draw 21 Amps of current, for a maximum of 205 seconds without damaging the inside of the motor?
2) In a situation where the maximum current is being drawn, does it mean that 21 Amps are going through EACH of the 3 black wires or does it mean that a total of 21 Amps are going through the 3 wires together, into the BLDC motor?

Motor picture is below, friends.
Thank you my friends for the replies.

Last edited:

#### nsaspook

Joined Aug 27, 2009
10,706
21 Amps of current, for a maximum of 205 seconds without damaging the inside of the motor? Depends on the degree of cooling.

By convention we usually describe a three phase load by the current in one phase.

Joined Jul 18, 2013
26,291
Although if true BLDC there is only two conductors carrying current at any one time, no 3 phase applied.

#### Irving

Joined Jan 30, 2016
3,190
Which datasheet are you reading - can't see that limitation for the KDE 8218XF-120

#### Track99

Joined Jun 30, 2022
38
Which datasheet are you reading - can't see that limitation for the KDE 8218XF-120
You are correct Irving. I used rough numbers, for this post, and a rough picture, because I didn't have the motor in front of me on the table.
The real numbers are: Maximum Continuous Current* 142 A (180 s).
It is a KDE10218XF-105

#### Track99

Joined Jun 30, 2022
38
Although if true BLDC there is only two conductors carrying current at any one time, no 3 phase applied.

Thank you my friend.

From your post I will make 3 guesses:

1) When measuring the current, we will see a total of 21 Amps drawn , together, by 2 of the 3 wires ( by wires, I mean phases).
I am guessing, if we measure the current in all three phases, then we will see a total of 21 Amps drawn together by ONLY, ANY 2 wires at any given point in time.
2) We will never see 21 Amps drawn through ONLY one wire ( by wires, I mean Phase. )
3) We will never see 21 Amps drawn though ALL 3 wires. ( by wires, I mean Phases. )

Are my guesses correct my friend?
Thank you

Joined Jul 18, 2013
26,291
At any given time during operation, one conductor only, will be non-conducting.
Current will be carried by the other two.

#### JuliaSmith

Joined Nov 9, 2022
6
Yes all 3 wires will conduct a total of 21 A current and the maximum power the motor that the motor can consume is 21A.So technically the motor will provide it highest speed with 21 A of current supply