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Millermatic 30E dynamic braking question

jzr75601

Jun 27, 2020
1
Joined
Jun 27, 2020
Messages
1
Hello All
This is my first time posting on this forum
I have this old Millermatic 30 E wire feeder which is part of a mig welding machine.
The problem I'm having with it is, the wire feeder continues to feed wire for a fraction
of a second after releasing the gun trigger which causes the welding wire to "over feed"
at the end of a welding cycle.The wire should actually stop immediately to prevent this
condition.
The motor which feeds the wire uses "dynamic braking"( large high wattage resistors switched across the motor leads)to accomplish this. .
So I posted the schematic of which I pointed out the two resistors in the schematic which I think actually perform this function, Any help is greatly appreciated.

Scan_20200625.png
in hopes that some one might be able to explain the circuit better than I understand it.
 

Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
Messages
6,901
Sounds to me like the burn back controller is playing up.

.......or you have it adjusted incorrectly
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
There is an SCR which i think would be switched on to brake. Check this.
My eyes are too dim to read the device values.
 
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