Author Topic: PWM Current > 3 Amp  (Read 4276 times)

venkut

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PWM Current > 3 Amp
« on: May 25, 2012, 03:28:23 PM »
I have a one application where I have to use 3.5 Amps to allow 100% flow for proportional solenoid. I am using 24-20 micro-controller, Is there anyway, I can use 2 PWM pins to generate 3.5 Amps on the coil? Is there any alternate method is available? I really appreciate your responses.

Offline pinias

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Re: PWM Current > 3 Amp
« Reply #1 on: June 12, 2012, 07:02:27 PM »
Venkut,

I have done some applications where the load has high current consumption so my controller PWM output is driving a SSR. It makes things easier and you protect the controller.

I hope this helps.

Regards

venkut

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Re: PWM Current > 3 Amp
« Reply #2 on: October 22, 2012, 06:14:48 PM »
Thank you for the reply. Would you mind sharing what exactly have you done when high amp needed?

Offline Marbek_Elektronik

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Re: PWM Current > 3 Amp
« Reply #3 on: June 02, 2020, 02:43:11 PM »
Now, 8 years later I have the same problem:

What is the maximum current at PWM Output? Is it 5A or 3A ?

The controller will shut down the output between 5,00 and 5,25A.

We want to use the outputs because we can look to the current via servict-tool. No relais.

Look here: Technical InformationPLUS+1® MC0XX-1XX Controller Family
https://assets.danfoss.com/documents/DOC322258021780/DOC322258021780.pdf     Page 15

I have opened an old controller. There is a Mosfet and the specification is 35A at maximum.
But, OK, traces and other components shoult transport the current.

What ist the max. current, 5A? And what ist the long-time current, 3A?

It would be nice, if an technical ingenieur form danfoss could answer this question.
Thanks!
Marbek Elektronik, Dipl.-Ing. Bernd Konrad
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Offline Mike

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Re: PWM Current > 3 Amp
« Reply #4 on: June 02, 2020, 08:31:06 PM »
I've actually run into a similar problem. In my case I am using the output for a small 12V DC pump which draws around 2.3A but pulses cause large (500mA) fluctuations in the amp draw. My output status is often tripping the overload status, it then shuts off the output until the signal to the ouptut is turned off for 200ms (as indicated in the manual).

As you mentioned per the specification sheet the ouptut should be capable of 3A continuous with an instantaneous trip of 5-5.25A. Would seem to me that they are using a re-settable thermal fuse. With something like that it would trip at less amperage over a longer duration. So with 3.5A it may trip but instead of instantaneous it may take more like 5 minutes. though it could also be a combination of fuse and part of the software in hardware template that is protecting the outputs. IE digitally turning off the output if the feedback value is greater than 3A with the fuse as a backup.

If you have a junk/test controller you could always try connecting the outputs in parallel and just make sure that they are both activated at the same time. Add the feedback values together to get the actual current draw.

Offline jashom1

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Re: PWM Current > 3 Amp
« Reply #5 on: June 03, 2020, 03:38:44 AM »
If you can justify it, have you thought of using an MC018? HEAPS of current available there :)

Offline Marbek_Elektronik

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Re: PWM Current > 3 Amp
« Reply #6 on: June 03, 2020, 05:36:43 PM »
We use MC050-110, OX024 and MC024-130 in this machine. Normal PWM outputs.
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Offline tronelec

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Re: PWM Current > 3 Amp
« Reply #7 on: June 04, 2020, 01:43:34 AM »
Remember to connect the additional power supplies according to the controller, for example in mc024-120 you must connect positive c1p2 and c2p11 and c2p12. it can add two outputs so configured as supply source to reach 6 amps with two outputs parallel to a solenoid (google translate)

Offline Marbek_Elektronik

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Re: PWM Current > 3 Amp
« Reply #8 on: June 06, 2020, 07:20:48 AM »
Thanks, (we allways connect all positiv pins to power)
but often, there are not enough pins. So, we need a little more than 3 A at 1 PWM-Output by digital configuration, no PWM current or PWM voltage. Just On or Off.
Actually the current is 3,2 A and it works.

But, is it allowed?
« Last Edit: June 08, 2020, 03:12:16 PM by Marbek_Elektronik »
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Offline Mike

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Re: PWM Current > 3 Amp
« Reply #9 on: June 08, 2020, 02:56:36 PM »
IMO depends on how strict you are about staying in the green vs edging into yellow. 200mA over is not a lot. It seems they are stressing the 5A as the hard limit for output tripping which you are well below. I do not however know the internal hardware or setup so I would test it out thoroughly before shipping.