# How to slow down AC motor?

#### Swab322

Joined Mar 7, 2019
9
I’d like to slow down, as much as possible this black and decker drill motor. I have it wired on a dpdt switch for fwd and reverse. I’m using it for a homemade router lift and I only need it in short burst to make small height adjustments. Was trying to make it with stuff lying around the shop. Or ... any suggestions for a similar set up? Need it to be 110v and a way to connect the drive shaft to a piece of 3/4 all thread.

Joined Jul 18, 2013
19,400
Is this a portable corded or cordless Drill?
If mains operated then it will be a Universal motor and a Triac controller should work, if a portable it is low voltage DC and there are many PWM DIY or ready made, cheap, out there.
Max.

#### MisterBill2

Joined Jan 23, 2018
4,490
Indeed, it might have a built in speed controller, but I am guessing not. An easy experiment, if it is a brush-type motor, is to try running it on 12 volts DC. You can try that first off a car battery, and if the speed is OK then one of those 12 volt or 19 volt power supplies from a resale shop can drive it and you are all set. That is about the cheapest way and it may have enough torque for your application. If you need a lot more torque then a worm gear reduction system is the best choice. There are some really interesting simple cheap ways to make a worm gear set that I have seen. If you are interested I can provide a description.

Joined Jul 18, 2013
19,400
They will most likely both be brushed motors, either low voltage DC or AC fed Universal.
Also both normally come equipped with gearing of some kind.
Max.

#### Swab322

Joined Mar 7, 2019
9
Is this a portable corded or cordless Drill?
If mains operated then it will be a Universal motor and a Triac controller should work, if a portable it is low voltage DC and there are many PWM DIY or ready made, cheap, out there.
Max.
It’s a corded drill..

#### Swab322

Joined Mar 7, 2019
9

#### Swab322

Joined Mar 7, 2019
9
There will obviously be a router in the clamp but this is essentially what I’m trying to accomplish. It works at full speed just fine but I’d like to tame
Indeed, it might have a built in speed controller, but I am guessing not. An easy experiment, if it is a brush-type motor, is to try running it on 12 volts DC. You can try that first off a car battery, and if the speed is OK then one of those 12 volt or 19 volt power supplies from a resale shop can drive it and you are all set. That is about the cheapest way and it may have enough torque for your application. If you need a lot more torque then a worm gear reduction system is the best choice. There are some really interesting simple cheap ways to make a worm gear set that I have seen. If you are interested I can provide a description.
I’m going to hook it up to a dc supply right now didn’t think about that.. eventually I’d like to make it less jerry rigged and just order the appropriate parts, looking for plug and play. I.e. up down switch, motor, and the correct linkage. Just trying to see if it will all work as designed right now.

#### Swab322

Joined Mar 7, 2019
9
Indeed, it might have a built in speed controller, but I am guessing not. An easy experiment, if it is a brush-type motor, is to try running it on 12 volts DC. You can try that first off a car battery, and if the speed is OK then one of those 12 volt or 19 volt power supplies from a resale shop can drive it and you are all set. That is about the cheapest way and it may have enough torque for your application. If you need a lot more torque then a worm gear reduction system is the best choice. There are some really interesting simple cheap ways to make a worm gear set that I have seen. If you are interested I can provide a description.
I’d like to see what you are talking about irt the worm gear set up.

Joined Jul 18, 2013
19,400
If you have torque to spare with the present set up, one of the really cheap 555 PWM controllers, either home built or ebay for a couple of $$. Max. #### MisterBill2 Joined Jan 23, 2018 4,490 One version uses a piece of that 3/8 inch threaded rod as the worm and a plywood disc with a groove cut in it as the gear. Another variation uses the same but requires using a piece of that rod quite hot to char threads into the wooden gear. With just a bit of char the carbonized wood provides a smoother and lower friction surface for the threads to run against. Fir height adjustment it would be OK as that is not a constant running application. And to keeepthem in the proper relative positions there is a wooden piece with cutouts for the gear and bearings for the worm shaft, made with three layers of plywood. It also can hold the grease on the gears. Does the explanation make any sense? Thread Starter #### Swab322 Joined Mar 7, 2019 9 If you have torque to spare with the present set up, one of the really cheap 555 PWM controllers, either home built or ebay for a couple of$$.
Max.
I don’t need much torque to turn it. I did try an old fishing rod building motor but it didn’t have enough. That’s why I started thinking drill. Just hooked up 9,12,&24v power supplies to it and I was only able to get “clicks”. Only sporadic turns with 24v. Hooked it back up to 110 and still works fine. Guess I’ll check out the PWM controllers

Joined Jul 18, 2013
19,400
Sorry, I forgot it is an AC version, so you need the Triac 'Dimmer' style, which again are fairly cheap.
Max.

#### Swab322

Joined Mar 7, 2019
9
Appreciate the input and pardon my ignorance.. if I just wanted to order the stuff to do this, what would I need to make this work? I need a motor with slow enough rpms, fwd and reverse on demand, enough torque to lift the weight of a router and it’self and 110/120v. I can sort out the linkage.. giving up on the drill lol. It won.

Joined Jul 18, 2013
19,400
What was the reason for nixing the drill idea?
So if you are starting from scratch you need an approximation of the torque required, the fact that you are operating into a threaded rod, this a means of offering gearing in itself as operating a threaded rod is form of lever.
The torque required can be obtained by a lever or a pulley etc of a known dia on the bottom of the rod and a spring scale to find the torque required to lift the heaviest estimated load point.
It may be possible with T.M. (Treadmill) motor and controller, or one of the KB boards on ebay etc.
If the torque is low, you may get away with a T.M. motor direct
Max.

#### Alec_t

Joined Sep 17, 2013
10,592
If the motor is an AC-driven universal type, how do you plan to reverse it?

Joined Jul 18, 2013
19,400
If the motor is an AC-driven universal type, how do you plan to reverse it?
He mentions giving up on the drill, by the look of it?.
Max.

#### Swab322

Joined Mar 7, 2019
9
He mentions giving up on the drill, by the look of it?.
Max.
I was ticked earlier.. giving up on harbor freight(that’s another topic) I’m gonna try again tomorrow thanks for the input!