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12v 5a PWM, how to test

pevweb

Nov 6, 2020
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Hi guys

I just bought one of these last week.
https://www.amazon.ca/FTVOGUE-Contr...07PN9BTFJ/ref=cm_cr_arp_d_product_top?ie=UTF8


I trying to use it to control a wiper motor.
for power I'm using a 12v 5a power supply. If I hook directly to motor I can make it turn.
If I try to put the PWM in the middle nothing happens.
how can I test this unit to figure out what's wrong. The red LED light comes on so that may indicate a problem, not sure as there no documentation that came with it

anyone have experience with these and how to test to see if there's something wrong with the PWM or maybe with how I wired it

thanks
 

pevweb

Nov 6, 2020
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oops,the title should read, 12V not 21V! but I can't edit the title it seems
 

bertus

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Nov 8, 2019
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Hello,

Do you see the blue potentiometer?
It says overcurrent next to it.
Try to adjust it and see what happens.

PWM controller adjust.png

I will change the title for you.

Bertus
 

pevweb

Nov 6, 2020
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I was wondering about that thing... how do you adjust this?

and thanks for the title change :)
 

bertus

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Hello,

The potentiometer can be adjusted using a small screwdriver.
It will adjust the overcurrent level.

Bertus
 

Kiwi

Jan 28, 2013
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The red LED is labelled as Alarm, so looks like there is a problem.
Q1 - Is the green LED also on, or just the red?

Q2 - Does the green LED light up without the motor connected?

Q3 - Is the wiper motor installed in a vehicle?
 

pevweb

Nov 6, 2020
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The red LED is labelled as Alarm, so looks like there is a problem.
Q1 - Is the green LED also on, or just the red?

Q2 - Does the green LED light up without the motor connected?

Q3 - Is the wiper motor installed in a vehicle?
the green was on when power when motor was on
I need to go test it again to see if light was on when motor not connected
it's not attached to vehicle, getting power from my 5am power supply
 

bertus

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Hello,

When the motor runs at the 12 V 5 A powersupply, then it should also be able to run with the controller.
It can be there is a PWM position that there is to less power for the motor to run and the motor will stall.

Bertus
 

Alec_t

Jul 7, 2015
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According to the ad the current limit is adjustable from 1A to 10A (although strangely the ad rates the unit as 15A ???). What is the stall/start-up current draw of the motor? If it exceeds 10A the unit may be shutting down to protect itself.
 

pevweb

Nov 6, 2020
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According to the ad the current limit is adjustable from 1A to 10A (although strangely the ad rates the unit as 15A ???). What is the stall/start-up current draw of the motor? If it exceeds 10A the unit may be shutting down to protect itself.
So I tested, on low speed I'm getting about 1.6 - 2 A and on high speed it goes up 6.6A , I checked again and my power supply is ^A and not 5 as I had mentioned. And me getting a reading of 6.6 i'm guessing is due to my multimeter not being high end?
 

pevweb

Nov 6, 2020
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Ok , so here are the parts

This is the power supply, as mentioned , 6amps (and not 5 as I had previously said). according to the diagram shown the negative would be the outside of the connector
IMG_3323.png
This is the connector I'm using to connect my power supply. I put the multimeter on it (on continuity) and found that the part that would touch the outside of the connecter is connected to the negative side on thw connector (left screw on image)
IMG_3324.png
So I connected the wire from the negative from the connector to the negative on the PWM (power side).


IMG_3325.png
This is the connection to the motor. from here I can switch the wires and it makes no difference. if I inverse the wires the motor will simply run in reverse
IMG_3326.png

so, anything wrong with any of this?
 

Alec_t

Jul 7, 2015
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I don't see anything wrong with the connections.
on low speed I'm getting about 1.6 - 2 A and on high speed it goes up 6.6A
Those are the currents at normal running speed. The stall/start-up current will be several times those values, albeit for a short time while the motor gets up to speed, so could well be higher than the 10A current limit and cause the PWM unit to shut down.
Check reply #5 in this thread.
 

pevweb

Nov 6, 2020
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I don't see anything wrong with the connections.

Those are the currents at normal running speed. The stall/start-up current will be several times those values, albeit for a short time while the motor gets up to speed, so could well be higher than the 10A current limit and cause the PWM unit to shut down.
Check reply #5 in this thread.
humm....well, here's a stupid question. How can a 6A power supply push more than 6A? like that much more.
and how could I test the stall/start current. If it's all hooked up and then I open the power should I see a high number for a fraction of a second type thing?
and say the thing is pulling more than 10A (which I still don't get with the 6A power supply) I would simply need to get a PWM rated for 20A or something higher like that?
 

Alec_t

Jul 7, 2015
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How can a 6A power supply push more than 6A? like that much more.
It depends on the supply construction, quality, type and method of rating (average or peak Amps). A linear supply will usually tolerate a short-duration overload without fuss if it's been conservatively rated, whereas a SMPS may struggle, die or have the smarts to go into shut-down if overloaded. To complicate things, supplies from less-than-honest online sellers may have exaggerated ratings (e.g. Chinese Wots? rather than genuine Watts :) ).
how could I test the stall/start current
If you have a multimeter, measure the motor resistance when disconnectd from the control unit and supply. Repeat for several positions of the motor's armature. Divide 12V by the resistance to get the stall current.
I would simply need to get a PWM rated for 20A or something higher like that?
A PWM unit rated honestly for 20A or above would have more chance of surviving. If the PWM unit doesn't have one, don't forget to include a suitably-rated reverse-biased freewheel diode across the motor to protect the PWM unit from the back-emf generated at motor switch-off.
If it's all hooked up and then I open the power should I see a high number for a fraction of a second type thing?
It's unlikely your meter would respond fast enough for you to measure the start-up current.
 

pevweb

Nov 6, 2020
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If you have a multimeter, measure the motor resistance when disconnectd from the control unit and supply. Repeat for several positions of the motor's armature. Divide 12V by the resistance to get the stall current.
.
humm, not sure I want to take the body out again, was so hard to put back in, could not center the thing because of the strong magnets . Testing from the leads won't be accurate enough?
 

Alec_t

Jul 7, 2015
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You don't have to remove the armature. Test from the leads. Run the motor briefly. Test again. Rinse and repeat. The idea is to average measurements which differ due to inconsistent brush contact with the commutator segments.
 

pevweb

Nov 6, 2020
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You don't have to remove the armature. Test from the leads. Run the motor briefly. Test again. Rinse and repeat. The idea is to average measurements which differ due to inconsistent brush contact with the commutator segments.
So i did that and obtained around 1.2 ohms , that would mean it's about 10 amps... but guessing it can go slightly over and that might explain why the controller shuts off I guess.
so , would getting something like this fix my issue?
https://www.amazon.ca/Controller-Ad...er&qid=1604888942&sprefix=PWM,aps,243&sr=8-11

and regarding a reverse-biased freewheel diode, that's something that would need to be soldered to the board on the PWM? I had to look that one up. Or is there a way to add that without the need to solder to the board?
 

Bluejets

Oct 5, 2014
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Usual place is on the output of driving transistor or mosfet but on the motor leads should work just as well.
I would tend to solder it in place though, whichever .......
 

Harald Kapp

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As the controller linked in post #18 is specifically designed to drive motors, a flyback diode is probably already on board.
In any case, as Bluejets stated, you can mount the flyback diode also in parallel to the motor connections. No need to solder it to the controller pcb.
 
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