DC Motor Torque with PWM Control: Bill Black in South Florida

In summary, a user is seeking clarification on how a DC brushed motor with PWM control will perform in terms of torque when operating at full voltage but a reduced duty cycle. They are unsure if there is a predictable mathematical relationship and have researched the topic extensively. They receive a response that the torque will go from 0 to 10 units as the duty cycle goes from 0 to 100%, and are directed to further resources on pulse-width modulation. However, they still have questions about how the motor perceives the applied voltage and the meaning of power percentage in this context.
  • #1
billblack
34
2
I had posted this is in "Electrical Engineering" but no one has posted any thing so I am posting g my question here as well.

I've done my best to find an answer to no avail. Can anyone offer some insight?
Subject: DC brushed motor with PWM control
If the motor has 10 units of torque @ full rated voltage in the spec sheet, what torque can be expected when operating at full voltage but a reduced duty cycle? Is there some predictable mathematical relationship? I'm hoping for 100% torque, but doubting the possibilities.
I await enlightenment,

Bill Black
waiting for Noel in South Florida
 
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  • #2
Well, I guess the torque will go from 0 to 10 units as the duty cycle goes from 0 to 100%

Have you looked at this: Pulse-width_modulation?
 
  • #3
dlgoff said:
Well, I guess the torque will go from 0 to 10 units as the duty cycle goes from 0 to 100%

Have you looked at this: Pulse-width_modulation?

Yes..I have researched this quite a bit past Wikipedia. I'd "guess" the same thing, but I was trying to avoid guessing.
The torque specs on motors are most often given in reference to the voltage applied. If the PWM is supplying, for instance, 10 VDC @ 60% duty cycle, does the motor "see" that as a 6 VDC applied to the motor or as 10VDC applied 600 mSec per Sec? Is there any difference between the two conditions?
Heck...maybe I am just analyzing this to death and @ 60% power means 60% power no matter how you name it.
??
Thanks!
 

1. What is a DC motor?

A DC motor is a type of electrical machine that converts direct current (DC) electrical energy into mechanical energy. It consists of a stator, which provides a stationary magnetic field, and a rotor, which carries the armature winding and rotates in the magnetic field.

2. How does PWM control affect DC motor torque?

PWM (Pulse Width Modulation) control is a technique used to vary the amount of power supplied to a DC motor by rapidly switching the power on and off. By adjusting the width of the on/off pulses, the average voltage and current supplied to the motor can be controlled, thus affecting the torque output of the motor.

3. What are the benefits of using PWM control for DC motors?

PWM control allows for precise control of the motor's speed and torque. It also reduces power dissipation, which can increase the efficiency of the motor. Additionally, PWM control can protect the motor from overheating and extend its lifespan.

4. What factors can affect the performance of a DC motor with PWM control?

The performance of a DC motor with PWM control can be affected by the supply voltage, duty cycle of the PWM signal, and the motor's load. Other factors such as the type and quality of the motor, as well as environmental conditions, may also play a role.

5. Can PWM control be used for any type of DC motor?

Yes, PWM control can be used for most types of DC motors, including brushed and brushless motors. However, the specific PWM signal and control method may vary depending on the motor's design and specifications. It is important to consult the motor's datasheet or manufacturer for recommended PWM control parameters.

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