Power Drill Speed Control

[Jye]

I pick up a cheap power drill from supercheap yesterday and will be using it to run a pump, but the speed control on it isnt the best So I am thinking of using an external speedcontrol and would like some words of wisdom from those in the know, is this motor speed control suitable? I dont mind making one from scratch but if there is a nice little unit out there I could use that would be great.

Cheers
Jye

 

[sintax69]

They work great have one on my grain mill driving a drill works fine and have been using it for about a year now

 

[Piste]

Just be careful that the drill is not thyristor controlled as it will create problems if it is the same electronic device as the drill.
Being a cheap drill it is probably just a variable resistance as opposed to a sophisticated electronic controller.
I'm pretty sure if you have the drill set at max it will negate the internal speed control and allow the external to operate unhindered.
Iain, electronic guru (used to be anyway).

 

[Jye]

Thanks guys, this is all good news :beer:

 

[Jye]

I picked one up this afternoon to test and it does work very well between 50-100rpm (the range Im after) There seems to be a minimum rpm and then you have some speed control above this.

Is this what you are finding?

 

[poppa joe]

Too late ..JYE..
But i use a plug in Kamrook type controller.Cheaper..
Works for me..
Cheers
PJ

 

[Jye]

Do you have a link poppa?

 

[poppa joe]

NO JYE
I got it at Garage sale
But any hardware Bunnings etc should have them
i use mine on a drill +bilge pump from tank To filter .Just like a double adaptor with control.
Cheers
PJ

 

[Jye]

Can you explain what it is? I have no idea :huh:

 

[poppa joe]

JYE
Plug it in to your wall socket..put your drill plug in ..and it has an adjustment on it.. just like a fan controller........Looks like a double adaptor..but with a controller
Cheers
PJ

 

[Piste]

Heres a fairly simple circuit if anyone wants to try to build one, just a simple bridge, couplke of electrolytics, SCR and diode, just change some of the specs to suit 240v.
http://home.maine.rr.com/randylinscott/aug99.htm

 

[Jye]

Haha Piste thats the same circuit I found before starting this thread, but I have never used a silicon controlled rectifier before. If you have had any experience with them and could point be the right direction for part from jaycar or RS components I will give the circuit ago.

Cheer
Jye :beer:

 

[Piste]

The specs are on the circuit and a call to Jaycar or whoever should yield the goods.
I used to work for Motorola semiconductors many moons ago and could have reeled off a part number, no longer I am afraid, but quoting 25amp with a 600piv should be sufficient to get the right bit, and they do run hot so adequate heat sinking is essential, one of those big black alloy finned heat sinks, and an insulating spacer if required, depending upon the SCR package.
If the SCR comes in a TO3 package they tend to dissapate heat a lot better, the TO3 is an oval flat metal can with two wires protruding from the base, the can is the third contact.
The initial voltage (120vac on circuit) is not that critical as the final wattage rating for us and out US counterparts comes out about the same.
Failing that how about using a small induction motor (read quiet running) with a gearbox.
Lapidary people use them for tumbling stones and use a simple belt and pulley system, the unit can run for a couple of weeks non stop to achieve the polish they require.
I know you already have the drill but it could be of use for anyone else wanting to make a similar unit for stirring.
Wouldn't be too hard to put together and neccessity is the mother of invention, and saving money.