Reverse rotation twice a second

Danny Vain-Nielsen

Joined Oct 26, 2015
4
Hi all!

I'm a an engineering student, and I don't know a whole lot about DC motors. Is it possible for a DC motor to reverse rotation twice a second? We need that kind of movement for a shaft. We might also have to make the rotational angle adjustable, meaning sometimes 180 degrees, other times 150 degrees. Is that possible and easy for a newbie to program?

Joined Jul 18, 2013
19,006
Depends on the inertia of the armature and the load.
Do you intend accurate positioning?
If so you either need PID feedback or use a stepper motor.
Max.

Danny Vain-Nielsen

Joined Oct 26, 2015
4
The torque is quiet heavy. 57 NM. Do you know an easy and inexpensive way to doing this?

joeyd999

Joined Jun 6, 2011
4,239
A linear actuator?

Joined Jul 18, 2013
19,006
57N-m, That is a considerable load, I envision some kind of gearing to use an small motor.
Is it possible to use a linear actuator to operate a small rack with a pinion on the shaft.
You may want to employ one of the free sizing programs to get an idea of sizing.
Such as Kollmorgen graphical motor sizing.
Max.

joeyd999

Joined Jun 6, 2011
4,239
57N-m, That is a considerable load, I envision some kind of gearing to use an small motor.
Is it possible to use a linear actuator to operate a small rack with a pinion on the shaft.
You may want to employ one of the free sizing programs to get an idea of sizing.
Such as Kollmorgen graphical motor sizing.
Max.
Why rack and pinion? Sounds like he just wants to move a shaft. Direct drive from the actuator.

Danny Vain-Nielsen

Joined Oct 26, 2015
4
I asked a big company doing linear actuators and they had none, that could move so fast.

Joined Jul 18, 2013
19,006
Why rack and pinion? Sounds like he just wants to move a shaft. Direct drive from the actuator.
Smaller linear actuator with extra gearing, there has to be some kind of linear to rotary connection anyway.
Max.

Joined Jul 18, 2013
19,006
I asked a big company doing linear actuators and they had none, that could move so fast.
How did they assume you were transferring to rotary?
Max.

crutschow

Joined Mar 14, 2008
23,306
Here are some high torque stepper motors (up to 50 Nm), but I don't know their cost.
You could likely use one of those with a gear reduction to increase the torque.

mcgyvr

Joined Oct 15, 2009
5,394
What about a mechanical solution like a crank so you never need to change direction but get the same motion effect..

Biff383

Joined Jun 6, 2012
50
30hz for any motor seems to be asking a lot. Maybe better to think about a solinoid? Way simple in the US. Not all that difficult in the rest of the world.

crutschow

Joined Mar 14, 2008
23,306
30hz for any motor seems to be asking a lot.
........................
Where did you get 30Hz?
The OP wants twice a second or 2Hz.

kubeek

Joined Sep 20, 2005
5,599
Probably mistaken for 30 RPM.

Biff383

Joined Jun 6, 2012
50

Biff383

Joined Jun 6, 2012
50

Joined Jul 18, 2013
19,006
I have a large NEW unused Bayside precision planetary through-hole gear box 15:1 with 180Nm output.
The original cost was around $2000 yours for$150.00 + shipping.
Max.

Last edited:

Danny Vain-Nielsen

Joined Oct 26, 2015
4
We will look at it... our budget is around 6500 € for everything the machine needs. But the school want us to buy only from wellknown companies.

I think the solution is to choose a 400 W DC motor and install to a constant speed at 60 rpm and then making a crank to get the forward and backwards movement.