Power for DC motor controller

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I bought one of these 24v DC motor controllers:
https://www.ebay.com/itm/311703088756
It came with zero documentation.  I found the basic connections on the  
web, but nothing else.

My question here is: it takes 12-24v DC in and with just a variac and  
bridge rectifier, it works.  But would it work better with a regulated  
supply?  I'm guessing not because of its own big cap and PWM output.  
But what do I know.  If regulated would be better, in what way?

I don't want to just add caps because it will have very intermittent  
duty and the fully-charged cap voltage would be way over the  
controller's rated 24v.

Thanks,
Bob


Re: Power for DC motor controller
says...
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Usually the motor controller will work better.  As the speed slows down  
the PWM will give much more tork at the low RPMs.


Re: Power for DC motor controller
On 3/5/2018 4:36 PM, Ralph Mowery wrote:
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Thank you.  It's the low speed that's most important in this case.

Re: Power for DC motor controller
On Mon, 05 Mar 2018 22:41:38 -0500, Bob Engelhardt

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The website says it is a PID controller.  That's probably way more
sophisticated than you need or want.  Do you have some tachometer
feedback signal?  (and do they provide enough info so you can tune it
for your motor and load?)

With all the extra connections, and board mounted switches, looks like
it could be tricky to apply.

Re: Power for DC motor controller
On 3/6/2018 1:05 PM, default wrote:
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"... enough info ...?  Zero, zip, nada ... that's the problem.


Re: Power for DC motor controller
On Wed, 07 Mar 2018 21:22:29 -0500, Bob Engelhardt

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If it is a DC motor and you have a DC supply I'd go with a simple PWM.
You can't filter the output of those, it defeats the purpose of
chopping the power to control speed...

A better solution is a variable output switched mode power supply then
you can filter and send smooth DC to the motor and hang all the caps
you want on the output if you want a "stiff" power supply.  

El cheapo PWM: https://tinyurl.com/y8sojspj

article on modding a SMPS for variable output:  
https://tinyurl.com/hztw8o3

off-the-rack variable DC supplies:
https://tinyurl.com/y7q22rnw

I've got a cheap "battery eliminator" style PS that I got on Ebay for
~$20, it only outputs 3-12V in 1.5V increments at 5+ amps.  It would
be child's play to make it continuously variable, just put a
potentiometer in place of the rotary switch.  Then it would need a
meter and be less useful for what I use it for, so I haven't done it.

Re: Power for DC motor controller
On 3/8/2018 6:17 AM, default wrote:

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Yeah, but ... I already HAVE the subject controller!  I went for a more  
sophisticated controller because of the extremely variable motor's run  
conditions:  it will run at low speed with no load, then a minor load  
will be added, then a major load.  I need the speed to stay more-or-less  
constant through these changes & not have to be diddling with it.

Re: Power for DC motor controller
On Fri, 09 Mar 2018 08:44:06 -0500, Bob Engelhardt

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Understood.  A PID controller can be tuned for load and the regulation
response can anticipate the power needed to maintain a set-point.  To
do that it needs feedback so it knows what the RPM is, then it has to
be tuned to your system.  

The scant information supplied does say it is for closed loop speed
control, and the info seems to suggest that can be an analog or
digital feedback.  You don't mention if you have some form of
feedback.(?)

Short of finding the manufacturer and getting some more info, I
wouldn't know what to tell you.  

I wouldn't be too crazy about PID control, any closed loop control
scheme should be able to maintain precise speed control.

Also you mention it will run at low speed.  Geared motors are better
choices as a rule.  180 watts is ~1/4 HP or less.

Re: Power for DC motor controller
Bob Engelhardt wrote:

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** The controller ideally should be supplied by a battery pack, a hefty
SMPS or a transformer based DC supply with about 30,000uF of smoothing.


....  Phil

Re: Power for DC motor controller
On 3/6/2018 1:23 AM, Phil Allison wrote:

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Thanks ... that's 2 yea & 0 nay.  I'm sure there's the parts in my  
"collection" for a regulator.

Re: Power for DC motor controller
On Monday, March 5, 2018 at 11:41:10 AM UTC-8, Bob Engelhardt wrote:
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Maybe you could Google the part number on that black square chip for a datasheet?  Or did the seller sand that off?

Michael

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