PWM and DC motors

Hello community,

I am currently using a DC motor, which specs are 24 V DC, rated current 14 A, and output 250 W. For my basic understanding, shouldn't 24 volt and 14 A generate 336 W? I am a little confused with it before I control my motor with 24 V and 14 A.

Also, I am applying to 24 V and 3.2 A to my motor, which makes 76.8 W. When I grabbed the cable and measure force, it generated only 23 to 30 W. What should I do to control with the Watt, which I expected.

Best,
gsung2

gsung2:
Also, I am applying to 24 V and 3.2 A to my motor, which makes 76.8 W. When I grabbed the cable and measure force, it generated only 23 to 30 W. What should I do to control with the Watt, which I expected.

Let's deal with the easier part first. 76.8 W is the input power for the motor. The output power depends on the conversion efficiency from electricity to mechanical power. The efficiency is likely to vary considerably depending on the speed of the motor.

Actually the same logic may apply to your other question - 24 V DC, rated current 14 A, and output 250 W. It is probably the case that it needs 336 W of electricity to produce 250 W of mechanical power.

...R

A medium motor of that size will have perhaps at best 80% efficiency (unless its brushless which
are usually better), and often less.

Any gearing will dramatically reduce efficiency - not uncommon to see overall efficiency 50% with
a gearmotor.

Brushed motors lose power as heat in the windings, and also to friction in the brushes (which is substantial).
At low speeds the efficiency drops, and if overloaded the efficiency also drops.

The larger the motor, typically the better the efficiency, and when you get to large industrial motors you
might see more like 95+% efficiency.

I should've thought about the efficiency of the motor. Thank you for your answers and have a nice day!