Actions
Forum Thread Details
  • State Not Answered
  • Replies 3 replies
  • Subscribers 301 subscribers
  • Views 1568 views
  • Users 0 members are here
Related
See a helpful answer?

Be sure to click 'more' and select 'suggest as answer'!

If you're the thread creator, be sure to click 'more' then 'Verify as Answer'!

Are there any down sides to using PWM on a motor?

colporteur

I'm evaluating the option of using a L298N Dual H Bridge Stepper Motor Driver Board  and an Arduino to drive an HO scale model railroad train locomotive.

I've read a few online posts that indicate it is possible. I have yet to find any suggestion there is a downside. I haven't seen any cautions or warnings. Mixing new and old technologies usually has it challenges. I was hoping to discover those before smoke signal become my first indication.

The layout has a number of different models of DC locomotives. Some of them are a very old. I have some concerns that PWM may not be healthy for them. I seem to recall reading something negative about PWM but I can't remember where I saw it or just a figment of my imagination.

If anyone has any resources they are will to share please post.

  • 0

    No issue whatsoever for model DC motors : ) PWM is the normal way to speed-control DC motors for a very long time, so any problem would have been discovered by now, and motors have not changed either (some have got fancier with special windings for smoother rotation and so on, but this has nothing to do with PWM or not). For very small motors, you can add an inductor in series, to smoothen out the average current if the PWM rate is very low.

  • 0 in reply to shabaz

    I'm hoping to bench test a few locomotives tomorrow at the layout. I was going to brush the snow off the car and turn over the engine but -25Celcius and going lower, I'll wait:)

  • 0

    As Shabaz points out PWM is a good way to control DC motor speed and power and it is a very efficient method of varying power. The mechanical inertia of the motor and load act like a filter so the frequency generally doesn't vibrate the system.

    The main drawback is that switching high currents at high frequency can cause a lot of powerline and rf noise. Switching power to an inductive load can cause unwanted voltage spikes if not addressed. These aren't usually a big concern with small DC motor applications, but there are methods to reduce PWM noise if needed.