28BYJ-48 and ULN2003 continuous or not

Using Arduino Motors, Mechanics, Power and CNC
1

Hi guys,

I want to drive a peristaltic pump with a 28BYJ-48 stepper and ULN2003 drivers.

I don´t want to get it too hot, because it should run around 4-5h at a time and the pump is made of 3D printed PETG.

If I aim for around 5 RPM, should I drive it continuously with 5rpm (programmed with the Stepper.h library) or choose a higher speed with delays between the movements so the pump also does 5 rounds in a minute? It doesn´t matter that the flow would be less continuous.

I would guess, that starting and stopping requires more current. But on the other hand the continuous drive method always needs power...

Thanks in advance :slight_smile:

Cheers,

Dodoka

2

I think you need to do some tests to see what effect the different options have on the temperature.

If you have a longer shaft between the motor and the pump there will be less heat-transfer.

I wonder if the bearings and gears in a cheap 28BYJ motor are intended for such extensive work?

...R

3

It looks like this. So the motor itself is on the fresh air for the most part :slight_smile:

I would have to make a completely new pump to implement a longer shaft...

Shouldn´t the bearings and gears be fine with such slow speeds?
And I sadly have no equipment to monitor the temperature for a long period...

4

dodoka:
And I sadly have no equipment to monitor the temperature for a long period...

If it doesn't hurt your finger it probably won't do the plastic any harm.

Shouldn´t the bearings and gears be fine with such slow speeds?

No all the gears are moving slowly - that's the whole point of gears. Complex products that retail for $5 are unlikely to have been designed with longevity in mind. That's why people pay $100 and up for parts.

...R

5

According to different sites PETG should be ok with up to 70-80°C. I hope the motor won´t be that hot^^ I just can´t test it in action because I don´t have the tube.

I found the motor for 1,26€ on Aliexpress, so it´s not that big of a deal. It would still be nice if it can bear the stress. If not, I´ll have to use a nema17 stepper.