Don't know but I would think your DC drive may damage the DC motor. Usually the field and armature run on totally different voltages. That is why the motor generator unit has two generators. One developing 240-280V and the other 110V.
Not yet clear which motor he has. A 1941 would probably have been the "inline exciter" MG unit.
Some of those (JLewis has one..) had 200-230 VDC fields rather than 115 VDC.
Odd, too the mention of not reversing. 10EE use Armature-reversing, AND NOT Field Reversing (lower current involved, but slower acting).
The Field supply - wotever and from wherever derived - does NOT want reversing at any time. Symptoms suggest the Armature and Field are paralleld/same source, ergo BOTH reverse, electrically, together, and.. do NOT reverse, physically!
Field source needs to be independent, not reversed. That is cheap and dead-easy, if not already provided for on a corner ofthe PWM drive's PCB.
PWM drives: Those CAN provide the nominal full 230 VDC off 230 VAC input where SCR types deliver only 180 VDC unless provided a boost transformer at input, but..
Most of those as are affordable (KB-Penta, and I have at least one such), rely on ability to keep a big fat capacitor charged, and do not fare well when the load is at or over 2 HP. Economics are less attractive above that point. Probably more a market-demand ==> sales volume issue than a technical one, but big, reliable, and
durable, capacitors get expensive faster than bigger SCRs do, so..
Worse, Monarch/Reliance did not limit themselves to the nameplate's nominal 230 VDC Armature Voltage. Many measurements taken by more than a few folks evidence actual operation at 250-265 VDC. I run at ~ 275 VDC, peak. Motor doesn't seem to much mind, 'coz it spends very little time up there.
That "reserve", OTOH helps to stiffen RPM stability when in the Field Weakened zone - which is MOST of a 10EE's power range.
"More info" on the drive specifics, plus sorting the reversing issue (probably dead-easy), would be helpful so a seeker would be comfortable it did not need a re-do.
And yes - if not "finish the WHOLE job", at least get those paid-for new cross and compound feedcrews into place to reduce worry as to whether they are, in fact, the right ones, arent missing bushes, bearings, etc.. etc.
Even with ... all that sorted, AND a recycled crossfeed dial and handcrank?
If still the bed was not reground, saddle & TS were not re-fitted, spindle bearings were not replaced?
I would not expect what is so far but a basic cleanup to command much over $3,000-$4,000 with those biggies still on the "to do" list. IOW - it is still a "project", and not yet a solid chipmaker.
"Do nothing", expect to discount it another thousand or so to he who mindeth not tackling a greater level of uncertainty.
2CW