Anyone know how to wire a drill motor?

[Travelover]

Maybe this is slightly off topic to tractors, but we have some pretty bright folks here..

I was given a bunch of old tools including a Milwaukee 3/8" 110v drill. It didn't work and when I disassembled it, I found that the reversing switch had crumbled. The trigger variable speed switch is OK. I checked on line and found the switch assembly is about $40! My thought is that I can replace the reversing switch function with a DPDT switch.

Anyone know how the two brushes and two field leads are supposed to be wired - i.e. are the brushes and field coils wired in series or parallel? Is the drill rotation reversed by swapping polarity between the brushes and the field?

Thanks in advance!

 

[Travelover]

OK, I'll answer my own post to help anyone else that might search this subject in the future.

I figured this out by trial and error by powering the drill from a 24 volt AC transformer temporarily, to minimize the "collateral damage".

The brushes and the field are wired in series. The drill is reversed by a DPDT (double pole double throw switch) which reverses the polarity of the field relative to the brushes (armature). New DPDT switch at Radio Shack - 2 for $2.99.

Satisfaction of fixing it myself, priceless.

 

[tinkertoys]

Good for you. nothing like figuring it out yourself sure gives one a sence of accomplishment.

 

[digger2]

Glad you got it fixed.
If it would'nt have been a Milwaukee,i'd say chuck it.But since it is a Milwaukee,great.
In my opinion,Milwaukee makes some of the best tools you can buy.
I started converting to Milwaukee about 10 years ago.As my old
"Crapsman" tools wear out,(that does'nt take long)i replace them with Milwaukee,and i havent
found a bad one yet.......digger2