What type of motor do I need ?

Hi guys,
I want to motorize this desk :

Till now I only worked with very small motors for things like toy cars/3d printers. And I have few questions:

  1. As an experienced people with motors, give me an educated guess : what torque do you think I need ?
  2. Under the same wattage, what motor will give me more torque and speed, DC or Stepper ?

I'm currently have this motor at home (left over from other projects) :

Do you think it is strong enough

Any input will be appreciated

  1. As an experienced people with motors, give me an educated guess : what torque do you think I need ?

An experienced person would never guess, they would measure the torque required.

  1. Under the same wattage, what motor will give me more torque and speed, DC or Stepper ?

Question cannot be answered without providing both power and speed.

You're forgetting several important factors before you can determine what kind of motor (and gearbox, possibly) is required.

  1. the amount of weight you've placed on the desktop and

  2. how fast you want the desktop to raise and lower.

With whatever motor and drive system you may choose, you also have to consider that lowering the desktop may require negative torque (braking) but this depends upon what type of mechanical system IKEA provides with the desk.

Making any assumptions about what is required to do this will most certainly be wrong.

Do you have the desk now, if so you can estimate torque by hanging weight on crank handle.

Unfortunately I do not have the desk now, I wanted to pre-order the motor, I will have the desk only on august.

Regarding the questions:
There will be probably 10-20kg on the desk.
And 60 RPMs should be fast enough (it is about the same speed a person will crank it manually).

I'm looking for a ballpark estimation to start with, not something very accurate.

tautau123:
Unfortunately I do not have the desk now, I wanted to pre-order the motor, I will have the desk only on august.

You really need to get the desk first.

Friction in the mechanism will have a lot to do with the torque needed by the motor…

A cheap source of high-torque 12v DC motors is a screen-wiper motor from a scrapped car - but whether it is enough I have no idea.

…R

Well, 5kg force on 20 cm crank * 60 RPM = about 62 Watts, but that's a wild, ballpark guess, probably doubling that wouldn't be out of bounds. :confused:

I’ve used that kind of desk before, they have a lot of friction in the mechanism to prevent it descending
if you sit on it. Yes, wait till you have your desk and can measure the torque, in the upwards direction
with full load - the friction is not guessable, you need to measure.

Then double that figure for good measure and select a gear motor with that torque on the output, perhaps
100 to 200rpm output speed is reasonable, I remember having to crank the handle a lot…

If we are allowed to guess, here's mine: an accu screwdriver/drill. The accu could be a perfect power buffer. Its charger can probably not handle the current that the motor needs, but the charger would just take care of charging when you don't run the motor.

The windshield wiper has probably the right rpm on the axis. The screwdriver has probably too high speed without an additional gearbox and using it on half effect would just creat heat on wrong place.

I use this to run up jacks under my camper. I bet it would work a treat on the desk!
And $19.99 at Harbor Freight!

CordlessDrill.jpg

Measure the torque first, before buying anything! As I said my experience is they have a lot of friction.