A reduction in power to the tool isn't done with a resistor as some people are suggesting could be done. The resistor would have to be very big and would get very hot. The way the power to the tool adjusts the speed (or indeed a tungsten light that might need dimming), is by using an electronic device that basically switches the mains voltage going to the tool on and off at a high speed. It basically chops the power going to the tool on and off very quickly. Maybe 100 times a second or more. If you set the control knob to make the tool go slower, the amount of time the power is off to the tool is longer than when it's turned on. Turn the knob to go faster and the power will become more on than off. This all happens in a solid state electronic device, usually a thing called a Triac. There are no actual swith contacts, it all happens within the device which is made from silicon and has no moving parts.
I've made one of these speed controllers in the past many years ago for my old mains powered drill. Firstly you must make sure that your controller is of ideally a much higher wattage than your power tool. And the correct voltage for your country. Secondly, don't run the tool for long at a time. As the tool is rotating much slower, so is its fan. So over heating of the tool can happen simply because of that.
How long did the dimmer switch last before it burnt out. I also need to do the same to sand car body panels. Does the dimmer switch take the Resistance load?
you should by an 2000w or 4000w dimmer which are very cheap.The grinders are commonly 500 to 850w which is much lower than the operating power of the dimmer.
A simple dimmer switch might end up burning out your grinder motor. An actual motor speed controller would be safer and better. You need to find out what kind of motor is in your grinder and then match it with motor speed controller to do it right. The simple dimmer might also get hot enough to start burning.
Hi, Thank you for sharing these informations, I'm looking to use a grinder as table saw, the blade rpm is under 10 000 but grinder is 12 000 rpm, so I decide to reduce the grinder rpm using somthing like that. Can you tell me tif the grinder still work as usualy? Did you feel any deterioration ? Many people says that reducing voltage (that what dimmer do) can dammage (or dammage) the motor. Thank you
Hi, I've used it quite a lot with the dimmer and haven't seen any problems or damage. The dimmer is inline and only temporary so can easily be taken out.
why its not working on variable speed angle grinder . Minimum speed at setting 1 of my angle grinder seems still too fast for polishing. i fear that it will burn paint of my car even at lowest speed at setting 1. how should i control or further reduce speed of my 6 speed angle grinder
@@StevenVacher I got a variac ready so I could slow down my grinder to avoid burning but i ended up not needing it. To my surprise, against all the conventional knowledge I found on TH-cam, I was able to use a ceramic oxide 40 grit disc from 3M with a small 1200RPM dewalt grinder without any burning on a knotty log. I believe it was a spruce log. I now suspect that maybe using a high quality sanding disc might prevent the burning issue. Perhaps it is the cermaic oxide breaking to form new sharp edges which keeps the disc sharp, or maybe 3M's discs just don't clog very easily for whatever reason.
A reduction in power to the tool isn't done with a resistor as some people are suggesting could be done. The resistor would have to be very big and would get very hot.
The way the power to the tool adjusts the speed (or indeed a tungsten light that might need dimming), is by using an electronic device that basically switches the mains voltage going to the tool on and off at a high speed. It basically chops the power going to the tool on and off very quickly. Maybe 100 times a second or more.
If you set the control knob to make the tool go slower, the amount of time the power is off to the tool is longer than when it's turned on. Turn the knob to go faster and the power will become more on than off. This all happens in a solid state electronic device, usually a thing called a Triac. There are no actual swith contacts, it all happens within the device which is made from silicon and has no moving parts.
angle grinder needs it by default! I will ad this to my laboratory :)
I've made one of these speed controllers in the past many years ago for my old mains powered drill. Firstly you must make sure that your controller is of ideally a much higher wattage than your power tool. And the correct voltage for your country. Secondly, don't run the tool for long at a time. As the tool is rotating much slower, so is its fan. So over heating of the tool can happen simply because of that.
Great vid! Any way of knowing the RPM?
How long did the dimmer switch last before it burnt out. I also need to do the same to sand car body panels. Does the dimmer switch take the Resistance load?
Hi KJV, I haven't used this setup all that much but I haven't had any issues with it so far...
Odd !!! My dad's initials are KJV 🙂
@@StevenVacher thanks for the information. I will give it a go. I'm a Christian KJV is Gods Eternal Word. King James Version.
you should by an 2000w or 4000w dimmer which are very cheap.The grinders are commonly 500 to 850w which is much lower than the operating power of the dimmer.
A simple dimmer switch might end up burning out your grinder motor. An actual motor speed controller would be safer and better. You need to find out what kind of motor is in your grinder and then match it with motor speed controller to do it right. The simple dimmer might also get hot enough to start burning.
Thanks for the heads up Matt, I haven't used it very much so haven't experianced any issues as yet. 👍
Yes, I agree...👍
Hi, Thank you for sharing these informations, I'm looking to use a grinder as table saw, the blade rpm is under 10 000 but grinder is 12 000 rpm, so I decide to reduce the grinder rpm using somthing like that.
Can you tell me tif the grinder still work as usualy? Did you feel any deterioration ? Many people says that reducing voltage (that what dimmer do) can dammage (or dammage) the motor.
Thank you
Hi, I've used it quite a lot with the dimmer and haven't seen any problems or damage.
The dimmer is inline and only temporary so can easily be taken out.
Very good idea.I use the same for my Drilling machine
why its not working on variable speed angle grinder . Minimum speed at setting 1 of my angle grinder seems still too fast for polishing. i fear that it will burn paint of my car even at lowest speed at setting 1. how should i control or further reduce speed of my 6 speed angle grinder
share link to purchase
Why the manufacturers did not installed a speed controller?
Cut production cost
Very good
does the angle grinder get hotter?
Not noticeably, that said, I've never actually measured it with any instrumentation.
@@StevenVacher im thinking of trying to use a variac to accomplish the same thing so hopefully that will also not heat up
@@hobomnky let me know how you go and how well it works :-)
@@StevenVacher I got a variac ready so I could slow down my grinder to avoid burning but i ended up not needing it. To my surprise, against all the conventional knowledge I found on TH-cam, I was able to use a ceramic oxide 40 grit disc from 3M with a small 1200RPM dewalt grinder without any burning on a knotty log. I believe it was a spruce log.
I now suspect that maybe using a high quality sanding disc might prevent the burning issue. Perhaps it is the cermaic oxide breaking to form new sharp edges which keeps the disc sharp, or maybe 3M's discs just don't clog very easily for whatever reason.
@@hobomnky Wow, that is interesting, I might give that a go. I'll have a look at where I can buy some 3M discs. Thanks for the heads up.
Most excellent!
Dimmer very work for no load speed machine (almost pure Dynamo)
You're going to burn that motor out. A dimmer switch is not the appropriate type of switch to do that.
fry up your motor in notime ;)