Velocity control for an induction motor

Thread Starter

Rufinus

Joined Apr 29, 2020
65
Hi everyone.

I´m going to buy a drill press. The one I´m going to buy have a regular induction motor (1.400RPM 220V 50Hz). You can change the velocity using the belts and pulleys. But sometimes maybe I want a finer velocity control.

Can I use this velocity control to adjust the velocity of that kind of motor?

Velocity control

Sorry, I haven´t found the version in english. The motor is 300watt.

And another question, when I reduce the speed of the motor, the torque reduces so much?

Thank you

Best regards

Mod translated.E
Specification:
Item Type: DC Motor Controller
Material: printed circuit board
Size: approx. 85 x 58 x 38mm / 3.3 x 2.3 x 1.5inch
Input voltage: AC 220V
Suspend current: 10A
Regulation voltage: DC 10-210V
Wiring type: fence terminal
Output voltage: linear under load
Maximum current: 20A
Speed regulation method: potentiometer (linear)
Control type: 500K with switch
 

ericgibbs

Joined Jan 29, 2010
12,214
hi Rufinus,
That unit looks suitable for speed control, the torque may be reduced, but by moving the drive belt onto a different pulley, it should be OK.
E
 

LesJones

Joined Jan 8, 2017
3,077
Eric, I do not agree. The motor is an induction motor which will only work with AC. The motor controller has DC output so it wil NOT work with that motor. There is no reliable way to control the speed of a single phase induction motor. You could probably get a small change of speed by changing the supply frequency but any significant change in frequency would cause problems with starting as the reactance of the start capacitor changes with frequency. There are two options. 1 Replace the motor with a three phase motor together with a VFD. (Variable frequency drive.) The other option is to fit a DC permanent magnet motor and use the speed controller in the link.

Les.
 

LesJones

Joined Jan 8, 2017
3,077
Hi Eric, It's easy miss something when reading a post quickly. It's a nice thought to send the PM to avoid the TS connecting it up.

Les.
 

GetDeviceInfo

Joined Jun 7, 2009
1,805

ericgibbs

Joined Jan 29, 2010
12,214
hi,
I use the second module listed above on my Capstan drill, lathe and other mains powered tools, works as a satisfactory speed control.

E
The one on the left image side.
 

Attachments

LesJones

Joined Jan 8, 2017
3,077
I agree with GetDeviceInfo. The 2KW device is a phase angle controller. It will work with series wound (Universal.) motors such as used in most mains powered hand tools but the motor on the TS's drill is a single phase induction motor. I also think the speed steps obtained by moving the belt between pulleys is close enough for drilling.

Les.
 

ericgibbs

Joined Jan 29, 2010
12,214
hi Les,
The adverts state Induction motor speed controller.?

My bench mounted Capstan drill is a single phase induction motor, puzzling.??

E
 

shortbus

Joined Sep 30, 2009
8,429
The OP may want to re evaluate thier needs in speed control.
I have to agree with this. As someone who has been a machinist for a living ~55 years and took machine shop in school for 3 years before that The drill press step pulleys are usually well thought out speed wise for the drills and other things that a drill press is used for.
 

MaxHeadRoom

Joined Jul 18, 2013
22,641
hi Les,
The adverts state Induction motor speed controller.?

My bench mounted Capstan drill is a single phase induction motor, puzzling.??

E
As most have pointed out, it is a roll of the dice when trying to control a 1ph AC induction motor with Triac etc speed control. this why all the DIY CNC'ers out there use a 3ph motor and a 1ph fed VFD for their AC spindle.
The 1ph motor VFD units have a history of dropping out of run when under load or low RPM's.
You find the Triac controlled motor, mainly 1/2 hp and lower in fan applications etc .
I would never attempt one on a drill press.
Some are re-purposing DC T.M. motors for this use, often available free at curb side pick ups! ;) .
 
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