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Solid State 10EE controller options

DaveC

Aluminum
Joined
Jun 4, 2006
Location
SF Bay Area
I have a 1959 10EE and two Southcon aftermarket solid state controlers. Both controllers use speed pots to control the armature voltage and switches to control the field.

One controller has an SCR drive for the field, and uses a 3-position switch to generate three DC field levels. This configuration gives low, medium, and high speed operation.

The other controller has a fixed-voltage field drive and a switch that drops a 100 watt resistor in series with the field to weaken it for high speed operation. This configuration gives a low and high speed range.

My question is about which controller I should use. For its simplicity, I like the idea of the simple fixed-voltage field drive with its dropping resistor. However, I can imagine that the SCR field drive might ultimately give higher performance.

I am contemplating using a microcontroller to generate both the armature and field control voltages based on a single rotary encoder speed control. This would use the SCR field controller to emulate the original 10EE speed pot. What I don't know is if this would be worth the effort. I'd be interested in hearing opinions on how important the higher, "field-weakened" speeds are in everyday operation, and if there are any compelling reasons to go with the more complex solution.

Also, when my lathe was converted to solid state, the owner discarded the whole spindle control lever assembly. I'd like to incorporate that lever back into the new control electronics, so if anyone a lever assembly for sale, please contact me privately.

Thanks!

DC
 
Oh, one other thing.

If I do decide to make a microcontroller-based speed controller, I could easily add a pair of digititally-controlled potentiometers to emulate the original 10EE speed pots. If someone could describe the original pot (both mechanically and electrically) I'd appreciate it. I'd also need to know what DC power is available to run the microprocessor.

Of course, I'd make these available to folks needing replacement 10EE pots.

Thanks!

DC
 
Some aspects of the speed control pot were described Here.

Now, this description was for two separate pots, suitably interlocked.

An actual implementation with dual electronic pots would be somewhat different, of course, but the essential "crossover" feature would still be present.
 
The "field weakened" high speeds are very useful if you are using the EE as a collet lathe to do small diameter work.

But if you don't plan on that, then probably a 2000 rpm upper limit would get most other jobs done.
 








 
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