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Is this a suitable motor controller for a 1941 10EE?


Dec 28, 2022
My round dial 10EE has a functional drive motor, and the generator works with a basic DC circuit. The inline exciter is missing however, and I'd like to get more power, and better rpm stability under load. (I replaced the contactor box several years ago with help from forum members. The ways appear to have little detectable wear.)

Looks like the odds of getting a working inline exciter are slim. I found the thread on using a DC drive controller to power the original drive motor. Maybe the best route to go is a Parker SSD. Is this one for $599 decent price?

I have no idea how often these appear on eBay. Possibly it might be a good idea to watch for a while and see what turns up.

Did you notice that drive is in Dubai, United Arab Emirates?

If you can mount an encoder to the shaft, there are DC drives that will accurately regulate the speed.
I own two 10EEs. Both were a head ache to maintain with original drives. I ripped the old stuff out and went 3 phase VFD and could not be happier. One has run nearly 20 years now with no drive issues at all. I did the second one two years ago with a modern VFD rated motor and Hitachi VFD - no backgear. It is the sweetest lathe I have ever ran.

I do know many here think this is a sacrilege. It is possible to maintain the old drives. My meager understanding of the 10EE is it controlled both armature and field voltages to get more range. Today's drives do not do that. So, your best bet is to search for original equipment.
Karl T is right. I set up my VFD/AC drive for less than the 599.00 you want to spend. It runs like a swiss watch with power to spare, dead reliable and is quiet. Its nice have all original but its even nicer to have a lathe you can count on. Don
The 512C drives appear to be 2 quadrant drives, meaning you do not get regenerative braking. If you want a to use a Parker drive look for a 4Q (4 quadrant drive) like the 514C-16 drives. Keep looking as those prices are a bit high.
Thanks for the replies. I don't think that Dubai is generally known as a source of industrial equipment, so I'll steer clear of that deal. Ideally, a working inline exciter will pop up. I'm not wedded to keeping the original DC motor, but it does run.
I think abom on youtube has a series on running the original motor with two separate dc drives, one for the armature coil and one for the field coil, with a programmed controller to coordinate the two drives. I think they were planning on releasing instructions after completing the project.
If your speed control rheostats are working you only need the main controller. The second controller is only needed if you do not have a functioning rheostat to run the field voltage through.

I set mine up this way and it works well.
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Does your machine require 115VDC or 230VDC for the field. I'm not familiar with inline exciter versions. If it only needs 115VDC, I have an entire MG piggy back exciter unit from my 42 10EE I can sell you cheap.
Thanks for the offer, but the inline exciter is 230v and not compatible with the piggyback ones. Appreciate the tip on the controller(s), to the best of my knowledge the rheostat on my machine is in working order.
Walt, There's no reason that you can't get good performance with the basic setup that you have, that is, a stock motor/generator drive sans exciter. Your machine is currently using a bridge rectifier circuit in place of the exciter. There are lots of people using rectifiers in place of exciters and having good results. Let's figure out what's going on with your rectifier setup before you consider changing the drive.
Hi Cal,

Thanks for the guidance. It appears I'm priced out of a Parker 514C for the immediate future anyway. The one example I was able to find on eBay was $788. I can't spend that much right now because I promised my wife I'd finish building kitchen cabinets for our nearly complete remodeling project, and still need to purchase materials. My machining hobby has to take a back seat to that.

Thanks for all the ideas.

I spent some more time on this project, and dug through some old notes. I had set it aside at the point that I got most of the electrical problems sorted out, with help from forum members. The AC motor and DC generator unit would spin up, but it ran poorly with lots of arcing at the armature and brushes. Cal had observed the generator armature appeared to be dirty, but I got pulled away by a prior commitment and never followed up until yesterday.

I disconnected the power, pulled out the brushes, and used 600 grit sandpaper to clean it. I reshaped the ends of the brushes which had become distorted. Only one side of each brush had been clipped down, resulting in uneven wear.

The lathe now runs with no arcing at the brush and armature assembly, and it spins up well, at least to 2000 rpm (by the lathe's dial). Can't judge the power under load until I buy a tool post, but things are looking much better. I am operating with a very simple 4-diode rectifier circuit running off 120v AC to replace the missing exciter. It may be all that I need, but I want to figure out what kind of performance I'm giving up, if any by not having a variable exciter source.

The feed mechanism is difficult to engage, and the lathe makes a lot of noise when it is engaged. I need to do a lube change at bare minimum. It probably is in dire need of cleaning too.

When I was working on the electrical components, this resistor was connected to the (broken) substitute exciter circuit that the lathe came with. Is it an original part of my machine? Sorry for the bad photo, broke the lens on my phone camera. The resistor is a ceramic tube about a foot long, and has a stamp that indicates it's an Ohmite Dividohm No. 1360, 100 ohms.