7 replies to this topic

[Jairus]

Been searching out parts to build my 3rd replica of a Gorski controller.
Got a question for you smart people.
What is the purpose of the brass straps?
They seem to be soldered to the power strip, some only one strip and this one two over the top.

 

 

I have replicated this best I can since that ebay item is nearly $200.

 

I think it's just to hold the heat sink steady, but was just wondering what you guys thought.
BTW, it's a double micro in the metallic blue Russkit handles.
Updates as they happen.

 

[Isaac S.]

My only guess would be that it brings more heat to the heat sink but there are more good pictures here if you need them- https://www.facebook...76295014&type=3

[Jairus]

Well, thats funny.
The gold one is the second one I made.  Notice the JHW logo?

[Isaac S.]

I bet you had seen it but there were lots of pics of the brass strip so still thought it might be helpful. I did see that one, I thought you just painted the handles but now I know that you made the whole thing. 

[old & gray]

Hi Jairus,

 

I still have my Gorski Double Micro controller from 1968. It’s a little more original than Abe Lincoln’s ax but it has been updated and repaired numerous times.

From the pictures and literature on the Gorski site I would agree the purpose of the brass band was to conduct heat from the resistor to the heat sink, however I would offer some comments.

• The last band on the resistor is the failure point. Other than when the controller is “full on” current is always flowing through that band. Drawing heat from the last band is the critical job to prevent resistor failure.
• Heat is removed in three ways conduction, radiation and convection. For conduction there must be a direct path of contact. This is the most efficient way to transfer heat. Radiation occurs across the air gap between the resistor and the heat sink.
• Personal opinion; I don’t like the brass band. There is not a solid bond from the brass to the aluminum but worse with the band the heatsink becomes a power hot surface. Any contact of the heatsink with either the brake or track posts/clips will most likely result in a short circuit and a heck of an arc burn.

[Jairus]

Image saved Bob, thank you!

[old & gray]

Image saved Bob, thank you!

 

Image was from Isaac's link in post 2; highlight is mine. 

 

I'll have to pull my Gorski back out, like I did in 1975, in 1995, in 2017 

[bbr]

the last band of the nichrome wire would pop all the time with the parma resistors. it was hard to solder to the power band again.

we JB weld coated the entire resistor and sanded the face flat for smooth operation.

so much simpler in the old days LOL, but needed multiple controllers of different resistor values