Technical Electrical Gurus- I've got a Question About Grounds

Forgot to mention: the pwm stays nice & cool too! Maybe because I’m running it off the low speed power?

 

Just an update: I did the mod with the relay as Trendz diagrammed above.

Except I must have made a mistake. But it has turned out to be a GOOD mistake: The PWM now works on all 3 speeds of the VA speed control. So say I want it at 60% of VA's designed low speed, I can get that. But click the VA speed switch to medium or high speed (without changing the setting on the PWM), and I also get 60% of whichever of those I choose.

This is exactly how I would have chosen to do it in the first place!

 

So, I am going to ask the question for those wondering....

What is a PWM?

 

Short for Pulse Width Modulation. A simple electronic form of regulating power to electrical devices, by simply switching the power on and off rapidly. 50% on and 50% off gives you equal to half the input voltage, i.e. it would make a12V bulb driven by a 12V battery light up as if it was connected to a 6V battery.
Works good for light bulbs, motors and similar "simple" devices, but not for more advanced electronics such as a radio.

 

Thanks. I wouldn't have guessed it.

 

Welcome to the modern age. Now, let's get back to traditional hot rods.

Sent from my Trimline

 

It's not quite that simple. On larger motor circuits not originally designed for this use, you also need current-limiting circuitry to control current inrush. Without it, the current can actually be higher and motor overheating can occur. This also reduces lamp life, as the thermal shock of being turned on and off is the main cause of lamp failure. There's several other factors that effect how well it works, including the frequency of the pulse widths.

 

It's NEVER that simple. But for explaining the function to grumpy old men that think electronics that has been around for 50+ years aren't traditional it may be good enough.

 

I think if I had air I would be happy enough.

 

I think it's a great explanation, to help someone understand what PWM is.

We use it in our robots...it's great. But it's not traditional hot rod stuff, even so.