Monarch 10ee retrofit

Hi! I am a new owner of a 1961 monarch 10ee, got a decent deal on it out of the Midwest. it sat for about 3 years that I know of. Mechanical seems alright a little greasy but the electronics seem to be shot, found a mouses nest in the back cabinet. Chewed through wires among other things. I would like to convert to solid-state and retain most of the functions of the modular drive system. I keep reading about the parker conversion but I'm not quite sure where to begin. Other owners of this conversion any info would really help.

As troublesome as the stock drive has the capacity to be, if you have trouble, you can get help. Once you convert, no one knows how to help you. Additionally, almost none of the drives are actually better than the original.

My suggestion is use the resources here[there are many who know a ridiculous amount about these drives] to get the machine turning so you can troubleshoot any lathe problems, then if the drive ends up problematic you can swap it at your leisure

I'm a fair way down the road on a Parker conversion. Before you do anything I would test the DC motor and make sure you have a good motor. No sense in pursuing either fixing the original or a conversion if the DC motor isn't working. Haven't done it myself but I believe a 12V car battery can provide enough voltage on the field and armature to turn the motor.

I started converting mine to a Parker setup because it had already been redone with a non-factory DC controller which was not functioning through the full RPM range.

If you do decide to pursue the Parker setup I'll be happy to discuss it with you.

Ergo22 said:

...the electronics seem to be shot, found a mouses nest in the back cabinet. Chewed through wires among other things...

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Can't imagine what "other things" mice could have chewed through, but wiring should be easy to repair as compared to completely converting this machine to another type of control. I'd rethink this decision.

My recently purchased 10EE was factory wired to run on 460-volts 3-phase. In order to convert it to run on 230-volts single phase, Monarch has advised me to change out two transformers plus a heater, which they are providing at a very reasonable price. It is important to me to try and keep all the original controls, as much as is possible.

So small update I pulled out the thyratron control and it appears there was a small fire in there along with what appears to be extensive damage. At this point given my knowledge I don't think the module drive is salvageable to me atleast.
Wasn't sure how to post pics as I'm new so here's an imgur Link showing the state of the electronics can get more pictures tonight if needed. Appreciate the help Monarch electronics Monarch electronics - Album on Imgur

rabler said:

I'm a fair way down the road on a Parker conversion. Before you do anything I would test the DC motor and make sure you have a good motor. No sense in pursuing either fixing the original or a conversion if the DC motor isn't working. Haven't done it myself but I believe a 12V car battery can provide enough voltage on the field and armature to turn the motor.

I started converting mine to a Parker setup because it had already been redone with a non-factory DC controller which was not functioning through the full RPM range.

If you do decide to pursue the Parker setup I'll be happy to discuss it with you.

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Not concerned about this as a buddies family owns a electric motor repair company.

Ergo22 said:

So small update I pulled out the thyratron control and it appears there was a small fire in there along with what appears to be extensive damage. At this point given my knowledge I don't think the module drive is salvageable to me atleast.
Wasn't sure how to post pics as I'm new so here's an imgur Link showing the state of the electronics can get more pictures tonight if needed. Appreciate the help Monarch electronics Monarch electronics - Album on Imgur

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looks like to me the insulation failed and burnt some wires, wire is cheap compared to a parker drive. A real of wire at the store is your next purchase.

labeeman said:

looks like to me the insulation failed and burnt some wires, wire is cheap compared to a parker drive. A real of wire at the store is your next purchase.

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It's more than just wire kinda hard to tell honestly alot of things are rusted or corroded. Some of the electronics are puffed up and it's all swimming in cutting oil and grease. I seriously think if I power this thing up I'll burn my house down lol. At this point I'm more looking towards other options I understand people won't be able to help me as much with issues but I'm hoping if I build it myself and really get to know the system I'll have an easier time diagnosing it than digging into a super damaged system that I know nothing about.

Ergo22 said:

It's more than just wire kinda hard to tell honestly alot of things are rusted or corroded. Some of the electronics are puffed up and it's all swimming in cutting oil and grease. I seriously think if I power this thing up I'll burn my house down lol. At this point I'm more looking towards other options I understand people won't be able to help me as much with issues but I'm hoping if I build it myself and really get to know the system I'll have an easier time diagnosing it than digging into a super damaged system that I know nothing about.

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Thas not a fire, hell son I have machines that get hotter'n dat on a good day

But seriously the real experts have yet to chime in, and at the end of the day you will do what you please, it is your machine. Be assured if you have to replace every string of wire in the machine, at least you will have a diagram to go by and numerous people who have been there and done that

Saying that, if I were going to do such a thing[24 years with a MG EE] I would go AC freq drive with a gearbox adapter. The machining is more complex than the electronics.

Good advice above on checking the motor

I see what look like patches of exposed fiberglass in the circuit board next to the thyratron. It certainly looks burned.

as many have said, for many reasons, do everything you can do to restore the original drive. You will be much happier in the end.

The reason to get the motor squared away is to compare costs. You can get the price of Parkers from ebay. Figure about another $500 for contactors, transformers, switches, wire, etc, depending on how much is salvageable from the existing electronics.

Compare that to the price of a VFD and 7.5HP AC motor.

Either way you’re investing both time and money. Once you start down one path it is wasted time and money to switch paths.

Like I said, I’m happy to help with a Parker conversion. Just don’t want you to regret going that way.

rabler said:

The reason to get the motor squared away is to compare costs. You can get the price of Parkers from ebay. Figure about another $500 for contactors, transformers, switches, wire, etc, depending on how much is salvageable from the existing electronics.

Compare that to the price of a VFD and 7.5HP AC motor.

Either way you’re investing both time and money. Once you start down one path it is wasted time and money to switch paths.

Like I said, I’m happy to help with a Parker conversion. Just don’t want you to regret going that way.

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What features do I lose with a conversion? If any? I'd like to keep load compensation

thermite said:

Before you consider the Module drive dauntingly complex or confusing, just think on this:

Nothing is hidden You can even see the electrodes inside the tubes.

With either of a VFD or DC drive, a single packaged circuit - one of dozens - can have more components than everything out in plain view on the "Hollow-state" drive.

So yes, it is TEDIOUS and time-consuming to replace every wire, clean every terminal, test and test again as you go.

But you do that one at a time.

So it can be done. It HAS been done.

And now that Tim has well-proven Solid State tube substitutes, there is no longer the issue of sourcing the big "semi-unobtanium" fire bottles, either.

- As to which is "better"? The "4Q" SSD - or any OTHER "Regenerative" DC Drive that is otherwise adequate (the Beel/BICL D510 proved to not be) does most things better than the Modular.

But we just don't have enough owners that have BOTH of:

- a PROPER SSD drive - with adequate full-isolation boost (290-320 VAC) on the input AND the required, not optional "ripple filter" to smooth the Single-Phase Drive.

And

- A Modular in good condition.

To do side-by side comparison. To see how much it actually MATTERS.

Surely both make chips.



An SSD from an empty hole is around $3,000, all new parts?

Repair of a module drive should be under $1,000?

Used parts, an SSD conversion CAN get there, too. Or even a tad lower, The Modulae drive transformer, for example, is re-usable with an SSD. That saves a significant chunk of money.

You have research to do. Parts to price, a decision to take.

First, vet the motor!

ONE will "creep" it. But TWO 12 V IC engine batteries in series move it a tad more naturally even if slowly. That can help you ascertain if it has any damaged windings or wedged commutator segments.

Patience is not easy. But it is cheaper than haste. And not by "just a lttle bit".



PS: Thanks, nothing personal. But I don't "do" the "Friends" social-thing.

I HAVE friends. I just need to reserve the ability to hammer them when on PM without worry I might unduly offend!

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I appreciate the info I really think if my motors good a dc regen drive is the best option for me. And no worries on the friend thing I only added to see if I could direct message you since I saw you commenting on alot of ssd posts.

thermite said:

PM has a "send Private Message" function I call "PM-PM". It only has a 50 message box size, and that includes copies kept of outbound. So I have that option switched OFF.

If you click on a(ny) member's loginID, the menu may also show "Send email to" Yours and mine are BOTH active.

That first email traverses "an" SMTP mailserver supporting PM. Not (ordinarily) the same resource set that runs the website.

Once either party has received such a message, "ordinary" email can flow, with attachments that PM-PM does not support... and with ZERO further resource load, thereafter, on any of the very busy PM resource set(s).

Win-Win, that can be.

Email me if/as/when there is a need.

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What are your thoughts on a vfd for this lathe? I've read that servo motors have similar properties to DC motors in terms of usable torque etc. I'm concerned with fitting a quality replacement system on here. I understand that purists say the monarch drive is the best while you say theres not enough good conversions to compare. I'm not made of money but anything in the realm of 4 grand is doable to me. Cheaper is better however I'm not one to sacrifice quality to meet a budget. So I guess I'm trying to grasp what my best option would be. Like I said I'm not sure on the operational status of the DC motor the soonest I can test is today. Tldr with a vfd or DC drive, beyond repairability what else will I lose with each from the original drive? I know the parker drive is capable of the load compensation which is a big thing for me. I also know vfds have active braking on the quality ones. I picked up this lathe stupid cheap so I got no tooling in a non operational condition. Mechanical seems fine everything has been cleaned and checked no grinding or odd noises.

I am also rebuilding a 10EE, my second. The purists here told me i was a fool to not repair the dead drive. After beating my head on the brick wall for a week+, I will be ripping all the old DC stuff out.

I've run my first 10EE twenty years with a five horse 3 phase motor with the original backgear and a VFD to drive it. never one problem. This is a big install job with a fair bit of machine work to mate the backgear to the new motor.


This time around, I plan to offer all the DC stuff for sale for $1250. If i get that I will go with a 10 hp 900 rpm motor ($1500) and VFD - no backgear. If it does not sell I will take the back gear assembly and mate it to a 7.5 hp 1800 RPM motor. In either case, the machine will be controlled by a top end VFD - not a chinese elcheapo one.

!0EEs run great with 3 phase and VFD, don't let the purists here tell you different.

The reason the 'purists' give the advice they do is that:

Most of the aftermarket controller installs are crap pure and simple, less than one in ten is comparable to the original.

If you do it right it is very expensive, and a tremendous amount of work

Oh, gee you spent a whole week troubleshooting a drive, how long do you suppose it will take you to troubleshoot a drive no one has any experience with?

If the old drive electronics are worthless, how do you expect to get 1200 bucks for them?

Do you want a lathe to make parts or a project?

It is not purist intentions, it is common sense

Ergo22 said:

What features do I lose with a conversion? If any? I'd like to keep load compensation

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You get load compensation with any of these (Monarch, Parker, VFD).

The Parker conversion basically involves two DC controllers. One to control the field and another to control the armature. The problem you run into is that those units don't completely coordinate. Most folks use two pots to control them independently. To increase RPMs you first increase the voltage to the armature, and then above a certain speed (depending on the motor) you then decrease current to the field. (This is a bit of a simplification, as the Parkers have internal voltage/current/impedance algorithms to compensate for load.)

This usually means two pots to control them. You can either use two knobs to do this, or come up with a mechanical system that interconnects the two. Neither system is perfect. For one, the armature control is Reverse -> stop ->Forward. Stop is mid-range, and either side of stop is faster forward or faster reverse. Until you get to full armature speed and need to use field weakening (the other knob) to go faster. The Monarch system included full field braking, anti-plugging (not allowing forward to reverse without braking first), and this field weakening all in one control knob. The basic Parker system relies on the operator to basically do all that manually by moving the two pots appropriately. I went overboard and am building a digital front end to do that. But I have a lot of electrical engineering experience. For me this is definitely a project I enjoy, not a "get-er-done" quickly to have a usable lathe. I have two other lathes that work fine.

The VFD conversion runs into problems with the reduction gear. Without the reduction gear it is really hard to get good performance over a wide RPM range like the original factory Monarch. You'd like good performance from roughly 20-3500 RPM. (Those exact number can be argued but it's the right ballpark). The low RPM is mostly useful for cutting threads. That is roughly a 180x range. AC motors with a VFD lose performance at the extremes (too slow or too fast). It's easy to get 10x out of a VFD and AC motor. Good performance over 180x is almost impossible. One way to compensate is use a bigger AC motor, thus 7.5 or 10HP is common. But alone that still doesn't get the full range performance. Monarch's DC motors came with reduction gear (I forget if it is 5:1 or 6:1) bolted on the DC motor. So the preferred VFD approach is to re-use that reduction gear. That reduction gear is not bolt-on compatible with typical AC motors with a keyed shaft. Monarch used a splined DC motor rather than a simple key going into the reduction gear. Various machining solutions are possible to adapt an AC motor to the reduction gear. A good inverter rated AC motor of 7.5HP and a name brand vector VFD along with the reduction gear seem to give torque and RPM stability performance that is probably on par with Monarch's DC solution. Close anyway, maybe not quite as good over the full RPM range, depending on getting a good motor and VFD.

Note that both solutions can be run off single phase 220V, but you're probably talking about getting a 15HP rated or 20HP rated 3-phase VFD to derate it to run on single phase input.

In regard to a VFD conversion without a back gear, has anyone looked into running vector duty TENV 900 or 1200 rpm 230-460v motor with a 460v input to increase the range ? A 5 hp motor of that type can be found pretty reasonably ( mine was NOS $400 but I scrounged for it ). Transformers are pretty common on the used market. Performance would start to erode at about 2200-2500 rpm but would still be decent at 3600 rpm. If not enough, a 7.5 hp motor can be had in the same 184 frame size or 213 if necessary. Dave

without the backgear, for sure you want a 900 RPM motor.

With an AC motor you have constant torque so as you cut speed you cut HP. About the best you can do is 5% rated speed. So a 10 HP is now a 1/2 HP motor. You need about that much to run the machine for threading.

Now top end is just a function of centrifugal force to blow the motor up. 900 RPM motors are built the same as 3600, just different wiring connection.

So you can run a 900 RPM motor from about 45 RPM to 3600 RPM. maybe should go more like 7% on the bottom so 60 RPM for bottom. Now I suggest belting it about 3:2 so you end up with 40 to 2400 RPM speed range.

Of course more speed range is possible with the back gear and much cheaper smaller 1800 RPM motors are fine.