Supplying Proper Voltage and Current to Peristaltic Pump

bertus

Joined Apr 5, 2008
22,270
Hello,

Here is an other idea for a bidirectional speed control:

bi_speed_contol.png

The schematic comes from the attached article.
You could control the speed with an external voltage from 1/3 VCC to 2/3 VCC on pin 3 of the LM324, in stead of the potentiometer.

Bertus
 

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MaxHeadRoom

Joined Jul 18, 2013
28,617
Why use a computer board of any capability just to deliver power to run a motor?? No logic function is needed just to provide a fixed DC voltage, and the power handling portions of the circuit need to be built up separately anyway.
So you apparently have insights into the OP's final intention?

I have never used the Arduino, but have used the lowly Pic for something like this that required more than a simple reverser.
Often these types of pump are used in a metered process so typically there would be one or more types of sensors in order to provide some kind of controlled measuring etc.
Max.
 
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Thread Starter

oquabili

Joined Aug 13, 2018
11
Those are BJTs, not MOSFETs.
The circuit I posted needs MOSFETs.
Do you understand the difference?

Where do you purchase parts?
Well this is a very early prototype, so I'm open to purchasing anywhere, but greatly prefer reputable retailers (Mouser, DigiKey, and Amazon is what I've been using the most).

I read a little bit about the differences between BJTs and MOSFETs so I do understand the difference now. If you have recommendations for MOSFETs I should use however, that would be helpful. Thanks.
@oquabili You don't have access to mains power?
If not, If used in a portable application etc. I would look at a LiPo, Lithium-Polymer battery or even a the small 6v lead acid as used in emergency lighting etc.
Max.
In this case, since it's an early prototype, I have a power supply that I can set the voltage on and use for now. I'll look into power solutions in a later prototype iteration, once I have the intended functions all working properly.

For now, I'm going to move forward on crutschow's idea, and see if I can get the wiring done properly. I'm still a little new to reading wiring diagrams.
 

MisterBill2

Joined Jan 23, 2018
18,167
At some power level relays become the smaller way to go. At several amps most transistor types will need a heat sink of some non-small size, while a relay arrangement can be smaller. Another advantage is that momentary high voltage spikes will usually not destroy a relay, while they can demolish a transistor. At 5 amps and 120 volts AC, or 90 volts DC, the smaller cube relays are much smaller and only two of the 4-pole types would be required.
 

Thread Starter

oquabili

Joined Aug 13, 2018
11
How about this version?
Max.

View attachment 162059.
This is awesome, and much easier for me to understand. As per the diagram, I'll use the IRF540 and IRF9540 for my N-channel and P-channel respectively. And as for the two relays, I believe I can simply replace those without output from the Arduino?

At some power level relays become the smaller way to go. At several amps most transistor types will need a heat sink of some non-small size, while a relay arrangement can be smaller. Another advantage is that momentary high voltage spikes will usually not destroy a relay, while they can demolish a transistor. At 5 amps and 120 volts AC, or 90 volts DC, the smaller cube relays are much smaller and only two of the 4-pole types would be required.
Thank you for the heads up. In my case, I'm running at very low power (Only 6V, 500mA) so I'm going to try with the transisters first.
 

MisterBill2

Joined Jan 23, 2018
18,167
Relays would be driven from whatever the control source is. There is a wide selection of control voltages available. But you would need some way to assure that only one or the other would be on at any time. Of course, that also applies to transistor "H" bridge arrangements.
 
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