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MIAC 8 bits controlling a DC motor > 1.75A

Posted: Fri Jun 30, 2017 11:21 am
by go233
Hello,
I would like to control 2 DC Motors;
they absorb more than 3A each.
I need also to change rotation direction of both.
Could you give me any suggestion, please?
Thanks
Giovanni

Re: MIAC 8 bits controlling a DC motor > 1.75A

Posted: Fri Jun 30, 2017 1:45 pm
by LeighM
Do you need speed control, or just on/off?
Perhaps you could use two MIAC relays to control the on/off power supply,
and use another pair of relays (or solid state outputs) to drive a pair of external DPDT relays to control direction.

Re: MIAC 8 bits controlling a DC motor > 1.75A

Posted: Fri Jun 30, 2017 1:53 pm
by Docara
Hi

More info required

What voltage for the motors
What control signal voltage (inputs)
3A ??? What is the peak value

Check the DRV 8*** range of MOSFET Bridge drivers eghttp://www.ti.com/lit/ds/symlink/drv8829.pdf is one I found with a quick Internet search

Hope it helps
Matt

Re: MIAC 8 bits controlling a DC motor > 1.75A

Posted: Fri Jun 30, 2017 3:46 pm
by go233
The motor is
RS Pro DC Geared Motor, Brushed, 12 V, 4.5 → 15 V dc, 2000 gcm, 3090 rpm, 19.8 W
RS Stock No.454-0877
Brand RS Pro
Mfr. Part No.942D51

the specs are attached to this post.
I think is a 2.85A at 12V.

Yes I would like to have speed control, too: I think if I connect the A and 0V to the input of an SSR I might sort it out?
Farnell
D1D20 - SSR, PANEL MOUNT, 100VDC, 32VDC, 20A
Manufacturer: CROUZET AUTOMATION
Manufacturer Part No: D1D20
Order Code: 1533374

What do you think?
Giovanni

Re: MIAC 8 bits controlling a DC motor > 1.75A

Posted: Mon Jul 03, 2017 11:15 am
by Docara
Hi Giovanni,

http://www.robotshop.com/uk/36a-drv8871 ... board.html - Assembled Board (£6ish)
http://www.ti.com/lit/ds/symlink/drv8871.pdf - Data sheet

Look at pages 8,9,10,11

You will see from the table on page 8 that you will need two PWM pins to fully control the motor with forward reverse and brake or toggle for 100% speed forward or reverse.
Page 9 how to limit the maximum current if desired
Page 10 outlines the inbuilt protection available
Page 11 shows a basic example of how to connect up

Edit : just seen this https://www.pololu.com/product/1213 and this http://www.hobbytronics.co.uk/dual-6a-d ... controller

Matt

Re: MIAC 8 bits controlling a DC motor > 1.75A

Posted: Mon Jul 03, 2017 3:29 pm
by go233
Hi Matt,
Ok, I will buy the driver and I will post my results.
(give me a week or so)
thank you!!!
Giovanni

Re: MIAC 8 bits controlling a DC motor > 1.75A

Posted: Mon Jul 03, 2017 7:09 pm
by Docara
Hi Giovanni,

Please check and verify for yourself if they are suitable for your specific requirements, don't just buy one because of my suggestion.

Matt