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Powder brake hack question - Brother HS-50A

SeymourDumore

Diamond
Joined
Aug 2, 2005
Location
CT
Guys

I know this may be a long shot, but I'll try anyway.

On my Brother, the board that controls the powder brake is flaky.
Sometimes it works, sometimes it doesn't with no apparent intervention.
I know things can behave in a weird fashion, but after some trouble shooting they either start working or go south for good.

Anyway.
My wire brake circuit is messed up. It is not the brake unit as I have 2 spares, they all do the same thing: When the brake is commanded ON, they lock-up as tight as they can.
Period, The End!
They go full-on brake to the point that the wire snaps at the pinch rollers in the back due to the wicked high tension.

After a very little research I've found that these things ( powder brakes ) are current controlled devices.
IOW, they are rated for a certain DC voltage ( in my case it's 24V DC ), and the amount of brake force is dependent on the current flowing through them.

So what I am trying to do is very simply this: Take a 24V supply and install a series potentiometer in the line to control the current.
For this machine I do not need ANY!!! accuracy for the wire tension!
It is literally a bandsaw for one part, and one part only!
Dedicated, does not cut anything else!
Right now I've actually disconnected the brake unit altogether and all I need to do is to stop the spool-bounce for a few seconds with my hand when the wire starts up.
After that the spool pretension is what keeps the wire tight enough for it to run.


Anyway, I plan to rig up something over the weekend, but does anyone have any insights into what I may run into?
As it is, I plan to use a couple of 12V batteries in series to power the thing just so I don't introduce anything that might damage a board that is now Unobtanium from
a company that has never acknowledged that these things ever existed.
 
Mount a rubber clamp against the wire spool to add drag. Prevent that initial hop. I did this year's ago on a machine.
 
Mount a rubber clamp against the wire spool to add drag. Prevent that initial hop. I did this year's ago on a machine.

That's actually what I'm doing right now with my fingers.
Only need it for the first 4-5 seconds for the hop to stop.
There is one odd problem though.
With the tension soo loose, the machine acts a bit weird when detecting short circuit.
It almost like it doesn't see it and just plows through until way way in trouble.


Regarding the adjustable power supply, I believe this is a current controlled device so that won't work.
 








 
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