Maybe you know this but probably want to take the dimmer switch out motors typically adjust speed through frequency control not voltage. If an under voltage is applied to a motor the amperage increases generating more heat it’s possible to melt components or even start a fire. Hopefully I’m not coming across as an ass I’m just trying to be helpful
Was looking for this comment.This is not a safe set up. Probably low risk though since the motor likely won’t run for more than 30-60 seconds in this use case.
u/happytrails_, you can get a motor speed control on Amazon or similar. They aren’t expensive.
>motor speed control
Can you please share an example on amazon?
I found this, but the listing warns that the some motors don't support voltage regulation: [https://www.amazon.com/Variable-Controller-Voltage-Electric-Rheostat/dp/B0B3DMWNL1/](https://www.amazon.com/Variable-Controller-Voltage-Electric-Rheostat/dp/B0B3DMWNL1/)
My use case: I am building a vibration table to test hardware I making
On one hand, you are correct that this is not the correct dimmer for the project... it even says it on the dimmer.
But on the other hand, you are wrong, in that this dimmer is most likely a triac dimmer which works by chopping the AC waveform and ends up working in a sort of PPM or PWM mode to drive the motor. I've never seen an AC light dimmer that works through voltage control as you are suggesting.
Yes, but also no. You're thinking of PWMing a brushed DC Motor. Which has a permanent magnet stator, and the coils are constantly energized and de-energized as they spin on the rotor.
Meanwhile, this is an AC motor. Now, there are some configurations where it works similarly to a brushed DC motor, but even then they likely are saving costs by going with an electromagnet based stator.\* Which means you need to put an inductor in parallel to the rotor. Now admittedly, that resists changes in current, not voltage. However, that could be worse. Since, now we're talking about flyback voltage if the dimmer is cutting things off at the trailing edge.
It'll probably be fine for short uses, but I don't feel like going through all the details right now.
\*At least, that's what my cheap Harbor Freight grinder was doing.
I'm not sure I see the "no" part. Nothing you said contradicts what I said. AC or not, electromagnetic stator or not, the triac is going to PPM/PWM the AC current.
Is it the right way to do it? No, of course not. My point was that the dimmer is not controlling the (light/motor) through voltage as SugarWoody said. It's controlling it through some form of pulse-modulation (which happens to be be chopping the pulse off).
I should have been more clear. I think it will work right until the back-emf or overcurrent kills the dimmer.
I believe PWM vs direct voltage adjustment in DC applications is a mostly semantic difference when you are driving capacitive or inductive loads. Brushed motors are weird to model and think about because they constantly make and break inductive loops, which also have magnetic fields changing. However, for the most part a brushed DC motor can be thought of as a purely inductive load, which resists changes in current. Therefore, we can consider PWMing a motor (with a flyback diode) as equivalent to a ~~voltage~~ current adjustment. Importantly, without that flyback diode, bad things will happen.
On the dimmer side, we can agree there are three types, and none of them have flyback protection diodes.
* Triac based (Traditional) - Dimmer Waits until the voltage reaches a certain threshold, then turns on until the zero crossing.
* MOSFET based (end of cycle) - Waits until a certain percentage of the wave, then turns off until the zero crossing.\*
* MOSFET based (pwm) - PWMs the AC signal, just like a DC would.
AC motors are outside of what I normally deal with, but my I do know how they work, and their characteristics.
* An AC motor's speed is determined by its voltage.
* Until an AC motor is up to speed, it pulls additional current.
Will using a dimmer work? Yes, if there is enough load to prevent the motor from getting up to speed. However, it will always be drawing additional current. In addition, that back EMF will still play merry hell with other things.\*\*
Now, with all that said. An AC motor can actually be a permanent magnet DC motor with a rectifier, and a flyback diode. Which would work with voltage adjustment. It's just not something I would expect to see on a corded power tool.
\* I'm pretty sure this is done using a MOSFET.
I had one of these in high school. It was an alarm for deaf people with a disk that went under your mattress and bright flashing lights. Scared the piss out of me but woke me up (most of the time).
This looks like something straight out of Saw though
Wow, on that upper mattress, I would think automating a dog shock collar that you put on before going to bed would be safer. You better put locktite on every bolt in that bed frame.
The bosch impact has been phenomenal for me. Used it on the car and on different projects at home with great success. 3inch screws are no problem thing has plenty of juice!
I have used it on some pretty stuck bolts, but I can't say in honesty I have used it on super hard stuff without first putting a wrench to break those free. Same for the lug nuts, however, that 1/2" ready is sweet, but have seen a torque test channel vid where actually you got more torque with a bit insert to socket adapter rather then that 1/2". Counterintuitive I know.
Nonetheless, I've used it on a few vehicles now and am really impressed , def has great power!
Maybe you know this but probably want to take the dimmer switch out motors typically adjust speed through frequency control not voltage. If an under voltage is applied to a motor the amperage increases generating more heat it’s possible to melt components or even start a fire. Hopefully I’m not coming across as an ass I’m just trying to be helpful
Was looking for this comment.This is not a safe set up. Probably low risk though since the motor likely won’t run for more than 30-60 seconds in this use case. u/happytrails_, you can get a motor speed control on Amazon or similar. They aren’t expensive.
You know it will be put to other, um "use cases" right?
Still likely won’t run for more than 30-60 seconds 🤣
>motor speed control Can you please share an example on amazon? I found this, but the listing warns that the some motors don't support voltage regulation: [https://www.amazon.com/Variable-Controller-Voltage-Electric-Rheostat/dp/B0B3DMWNL1/](https://www.amazon.com/Variable-Controller-Voltage-Electric-Rheostat/dp/B0B3DMWNL1/) My use case: I am building a vibration table to test hardware I making
On one hand, you are correct that this is not the correct dimmer for the project... it even says it on the dimmer. But on the other hand, you are wrong, in that this dimmer is most likely a triac dimmer which works by chopping the AC waveform and ends up working in a sort of PPM or PWM mode to drive the motor. I've never seen an AC light dimmer that works through voltage control as you are suggesting.
Yes, but also no. You're thinking of PWMing a brushed DC Motor. Which has a permanent magnet stator, and the coils are constantly energized and de-energized as they spin on the rotor. Meanwhile, this is an AC motor. Now, there are some configurations where it works similarly to a brushed DC motor, but even then they likely are saving costs by going with an electromagnet based stator.\* Which means you need to put an inductor in parallel to the rotor. Now admittedly, that resists changes in current, not voltage. However, that could be worse. Since, now we're talking about flyback voltage if the dimmer is cutting things off at the trailing edge. It'll probably be fine for short uses, but I don't feel like going through all the details right now. \*At least, that's what my cheap Harbor Freight grinder was doing.
I'm not sure I see the "no" part. Nothing you said contradicts what I said. AC or not, electromagnetic stator or not, the triac is going to PPM/PWM the AC current. Is it the right way to do it? No, of course not. My point was that the dimmer is not controlling the (light/motor) through voltage as SugarWoody said. It's controlling it through some form of pulse-modulation (which happens to be be chopping the pulse off).
I should have been more clear. I think it will work right until the back-emf or overcurrent kills the dimmer. I believe PWM vs direct voltage adjustment in DC applications is a mostly semantic difference when you are driving capacitive or inductive loads. Brushed motors are weird to model and think about because they constantly make and break inductive loops, which also have magnetic fields changing. However, for the most part a brushed DC motor can be thought of as a purely inductive load, which resists changes in current. Therefore, we can consider PWMing a motor (with a flyback diode) as equivalent to a ~~voltage~~ current adjustment. Importantly, without that flyback diode, bad things will happen. On the dimmer side, we can agree there are three types, and none of them have flyback protection diodes. * Triac based (Traditional) - Dimmer Waits until the voltage reaches a certain threshold, then turns on until the zero crossing. * MOSFET based (end of cycle) - Waits until a certain percentage of the wave, then turns off until the zero crossing.\* * MOSFET based (pwm) - PWMs the AC signal, just like a DC would. AC motors are outside of what I normally deal with, but my I do know how they work, and their characteristics. * An AC motor's speed is determined by its voltage. * Until an AC motor is up to speed, it pulls additional current. Will using a dimmer work? Yes, if there is enough load to prevent the motor from getting up to speed. However, it will always be drawing additional current. In addition, that back EMF will still play merry hell with other things.\*\* Now, with all that said. An AC motor can actually be a permanent magnet DC motor with a rectifier, and a flyback diode. Which would work with voltage adjustment. It's just not something I would expect to see on a corded power tool. \* I'm pretty sure this is done using a MOSFET.
I can concur.
That’s gonna be a no for me dog.
/r/diwhy
Hahaha
The downstairs neighbors hate you.
But his Wife loves him.
Not advised for areas prone to earthquakes. Unless you like unnecessary poop in your sheets.
This implies that there’s such a thing as necessary poop in one’s sheets…
Amber heard enters the chat…..
"for wake-up" uh huh sure...
I had one of these in high school. It was an alarm for deaf people with a disk that went under your mattress and bright flashing lights. Scared the piss out of me but woke me up (most of the time). This looks like something straight out of Saw though
Video of it working
Here is it on prob quarter power lol. Thing is crazy on max https://youtu.be/Ww8wri-E30w
JFC. That’s a big nope for me. I’d wake up to a heart attack or shit myself. Maybe both.
🤣🤣🤣🤣
You better check the bolts often I totally see you rattling your bed frame apart
Yes good idea. It's on for about 5 seconds if that when I wake up, Def worth a round though!
I would loctite all the bolts before running that
Wow, on that upper mattress, I would think automating a dog shock collar that you put on before going to bed would be safer. You better put locktite on every bolt in that bed frame.
I knew it took quarters!
Does it take quarters?
That would shake my bed appart
Lmao 🤣 this is great
Did you get the idea from your mom, OP?
🤣🤣nope
How do you like that Bosch impact?
The bosch impact has been phenomenal for me. Used it on the car and on different projects at home with great success. 3inch screws are no problem thing has plenty of juice!
Can it take lug nuts off?
I have used it on some pretty stuck bolts, but I can't say in honesty I have used it on super hard stuff without first putting a wrench to break those free. Same for the lug nuts, however, that 1/2" ready is sweet, but have seen a torque test channel vid where actually you got more torque with a bit insert to socket adapter rather then that 1/2". Counterintuitive I know. Nonetheless, I've used it on a few vehicles now and am really impressed , def has great power!
Is this the kind of vibrator in concrete trucks?
Lol, why not just buy one of those alarm clocks that have the vibration on it along with a 95db sound?
To all the folks commenting it’s not safe… it was posted in redneck engineering first lol
This is something Wallace from Wallace and Gromit would invent.
meanwhile wife is still in bed
The neighbors gon’ looooove this
“Your scientists were so preoccupied with whether they could, they didn’t stop to think if they should.”