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Overview notes of single phase conversion options for Monarch 10ee

RatchetWerks

Plastic
Joined
Nov 12, 2023
Hey all,

I recently purchased a Monarch 10ee MG unit. I need to convert it to a single phase unit. I have done some research and took notes. Here they are below. Can you guys fact-check my research? Hopefully this helps others make a decision in the future. Personally I only consider options 1-4 viable.

Follow on questions:
1. Does anyone have a direct part number recommendation for a DC motor controller for option 3? Is BICL reputable/in-business? Does anyone have hands-on experience with them?
2. Does anyone have hand-on experience with VFD'ing the OEM 3PH motor with the appropriate line filters (to avoid high voltage spikes)? Since the VFD is going to run at a single constant RPM + line filters. I don't think it will burn up the OEM 3 PH motor.


Research Notes:
  1. Steelman Method:
    1. Summary: Open up the OEM 3PH AC motor, and re-wire internal winding.
    2. Cost: $200
    3. Time: 1 weekend
    4. Pros:
      1. Keeps all OEM parts
      2. Reversible back to 3-Phase configuration
      3. Zero tuning/integration needed
    5. Cons:
      1. High starting currents(Brown out risk)
      2. OEM levels of noise
      3. OEM level of MG efficiency
    6. Reference: PM Post
  2. VFD on old OEM 3PH Motor
    1. Summary: Add VFD to OEM 3PH motor
    2. Cost: $1000
    3. Time: 1 weekend
    4. Pros:
      1. Not invasive to machine, no OEM parts removed.
      2. Minimal tuning/fiddling
      3. Low-ish start up inrush current
    5. Cons:
      1. Might burn out OEM 3 phase motor windings if no line filter is used
  3. DC Solid-State Controller
    1. Summary: Bypass all of the Motor Generator logic, provide pure DC power to the motor via solid state controller
    2. Cost: $1500
    3. Time: 1 weekend
    4. Pros:
      1. Cleanest solution while retaining all the OEM parts in the machine
      2. Can be switched back to a MG setup, via wiring changes only
      3. Lowest noise levels
      4. No extra moving parts
      5. Not invasive to machine
    5. Cons:
      1. If DC controller fails, it could fail the OEM DC motor?
      2. DC Controller Company may not be in business anymore?
    6. Reference: LINK
    7. Thoughts: This seems to be the “best” solution if the company is still in business.
  4. VFD + Inverter motor to direct drive the back gearbox
    1. Summary: Rip out everything. DC Motor + Motor/Generator unit , replace with VFD + inverter grade motor direct driving the spindle.
    2. Cost: $2000
    3. Time: 4 weekends + machining favors to be pulled
    4. Pros:
      1. Modern drive technology
      2. Minimal parts in the loop
    5. Cons:
      1. Removes many OEM parts
      2. Loses the “soul” of the machine
      3. Cannot easily revert back to OEM spec
      4. Need to store/sell/scrap MG unit
      5. Becomes a “project” to tune and fiddle with
    6. Reference: LINK
    7. Thoughts: While this is the “best” modern technique, it is very invasive, requires a bit of tuning magic to get everything to just work well, and remove the soul of the machine.
  5. VFD + Inverter-rated 3PH motor driving OEM DC generator
    1. Summary: Remove old AC motor, build adapter plate to drive DC generator
    2. Cost: $2500
    3. Time: 4 weekends + machining favors to be pulled
    4. Pros:
      1. Keeps the soul of the machine
    5. Cons:
      1. Most labor intensive option
      2. Many parts in the loop
      3. Seems silly from a system perspective: 1 Phase AC -> DC -> 3 Phase AC ->Shaft Power -> DC Generator-> DC Motor ->Shaft Power to spindle
  6. Static Phase converter:
    1. Summary: Attach a box that starts the motor with 3 phase, then run it steady state with single phase power to a 3PH motor
    2. Cost: $300
    3. Time: 1 weekend
    4. Pros:
      1. No moving parts
      2. No extra motor in the loop
      3. Doesn’t touch the OEM machine
    5. Cons:
      1. Reduced form OEM power output, since motor is partially powered
      2. Very bad efficiency since the motor is partially used.
      3. Seems like a poor bandaid solution.
    6. Thoughts: I don’t like this from a systems and engineering perspective
  7. Rotary Phase converter:
    1. Cost: $1000
    2. Time: 1 weekend
    3. Pros:
      1. Zero modifications to machine
      2. Might add more noise due to motor
    4. Cons:
      1. Bulky, requires external control box
      2. Silly energy conversion path: 1PH Power -> Shaft Power -> RPC (Generates 3rd leg of power via motor) -> 3PH OEM motor -> Shaft Power -> DC Generator -> DC Motor -> Shaft Power for spindle
    5. Thoughts: I don’t have space for the RPC, or like the energy conversion path.
 
Option #1 - Steelman: Grant G is working on a Steelman conversion. It's certainly taking him more than one weekend. When you peel back the hype, a Steelman conversion is just a fancy static phase converter (SPC) with run capacitors.

Option #2 - Run MG from VFD: This has been discussed. I don't know of anyone that's doing it. In general, finding a large enough VFD that runs from 240 single phase is a problem.

Option #3 - Solid-State DC controller:
I don't know if BICL is still in business or not. Be aware that his design was intended to drop into a Modular Drive base; putting it in a motor/generator (MG) base requires some gymnastics. I don't know if he relies on having the Modular drive's monstrous step-up transformer. The only BICL drive that I can recall being installed was done by Leo Williams, who sadly passed away a number of years ago.​
There are a number of Parker 514C DC drives in use. There's a information in the 10EE sticky. Some of the owners have had a bit of buyers remorse over scrapping their OEM drives. I DO NOT like the dual potentiometer control used in most cases; Ward-Leonard drives adjust EITHER the armature OR field, but not both at the same time; dual controls are an invitation for problems. Hobbyracer's 514C drive uses the MG potentiometers for single knob control. AFIK, the 514C is no longer in production, so you're going to have to find used or NOS stock.​
There are lots of other DC drives out there as well. KB makes one that's fairly inexpensive. Major problem that all but the BICL DC drives have is that that: 1) the controller doesn't directly support field weakening (the 514 solution used a 512 drive for the field and they aren't designed to work together for field weakening); 2) the drives are designed to work motors that use the same armature and field voltages (most 10EE DC motors have 230 VDC armatures, 115 VDC fields). Further, without a large, expensive boost transformer the drives (BICL included) only put out about 180 VDC.​
Option #4 - AC/VFD: Fine if your existing drive is missing or damaged beyond repair. Not my first (or second) choice.

Option #5 - graft AC motor to DC generator: IMHO, this is a non-starter. Way more complicated than it sounds. A much better option (but not an inexpensive one) would be to have a motor shop rewind the MG's AC section to be inverter rated.

Option #6 - Static Phase Converter:This by far the simplest and least expensive option. Several members here are using them. If you have the skills to do option #1, you can build your own SPC for probably $50. It can be as simple as a relay, a capacitor or two and assorted wiring bits. If run caps are added to help power the third phase, performance is better than the 2/3 rated power that you get without them. Start with an SPC and see if it suits your needs. You can always move up to an RPC by just adding a used 3-phase motor as an idler.

Option #7 - Rotary Phase Converter:
This is the most common solution for powering an MG 10EE from single phase. (It's what I use.) Again, you can build your own motor starter box (same box used as an SPC) for about $50. WNYSupply has kits for around $100 (link). Last I heard, used 3-phase motors sell for about $10/HP, so under $100 for a 7.5 HP idler.​
As far as there being a "Silly energy conversion path", I think you just don't understand how it works. The idler motor, in conjunction with the run capacitors, provides reactance to shift power from the two incoming legs to power the third phase. It's not like a separate motor/generator step.​
As to size, my RPC control box mounts on the wall and uses a common 8x8x3" junction box. The idler motor takes up about 2 square feet of floor space. Park it under a bench or against the end of the lathe (you DO NOT want to place the tailstock end of the lathe hard against the wall).​
on edit: correct inverter motor voltage
 
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There are many other options, depends on how much creativity you have flowing in your blood.

1. fluid drive. That is what a 1940 Sundstrand 10EE has (the first 10EE). I have mine running on a 3HP single phase motor.
2. True three phase. That is what I use for my shop. Phase Perfect.
3. 15HP RPC for shop power. Then you can run several tools at once.
4. A high quality DC power supply, with field weakening and resistors to enable a 2sec. shutdown.
5. 3phase from the power company.
 
Thank you all for the responses. Right now I'm doing some VFD research on option 2. I'll report back with my findings.

Cal, you're 100% correct, I'm not familiar with RPCs at all. All of my machines is crammed into 400 sqft. Finding the floorspace for the RPC is very difficult. I'd prefer solutions that would tuck inside the machine. If I had more floor space I'd give option 7 more thought.

Cal, for option 2. I think I found quite a few VFD units that will drive the OEM 3PH motor at 240v @ 5HP 3phase. (See screenshot below)

I'm leaning towards option 2 and don't mind using my MG unit as a test mule.

Are 180VAC operating voltages common in the states? I've only seen 120/208/240/280/600V AC induction motors prior. I did a quick google search. Most 180 VAC motors are spec'd for DC motors.

1700142705214.png
 
Sorry, I must have been thinking about DC motors. You're correct, inverter duty motors are typically 240/480. I'll go back and fix my earlier post.
 
  1. Static Phase converter:
    1. Summary: Attach a box that starts the motor with 3 phase, then run it steady state with single phase power to a 3PH motor
    2. Cost: $300
    3. Time: 1 weekend
    4. Pros:
      1. No moving parts
      2. No extra motor in the loop
      3. Doesn’t touch the OEM machine
    5. Cons:
      1. Reduced form OEM power output, since motor is partially powered
      2. Very bad efficiency since the motor is partially used.
      3. Seems like a poor bandaid solution.
    6. Thoughts: I don’t like this from a systems and engineering perspective
  1. Static Phase converter:
    1. Summary: Attach a box that starts the motor with 3 phase, then run it steady state with single phase power to a 3PH motor
    2. Cost: $300
    3. Time: 1 weekend
    4. Pros:
      1. No moving parts
      2. No extra motor in the loop
      3. Doesn’t touch the OEM machine
    5. Cons:
      1. Reduced form OEM power output, since motor is partially powered
      2. Very bad efficiency since the motor is partially used.
      3. Seems like a poor bandaid solution.
    6. Thoughts: I don’t like this from a systems and engineering perspective
FWIW. I've not said anything because I don't have a lot of time on it yet, maybe 8 hrs, but so far my SPC has been running just fine. No difference that I can tell with the RPC. I do have to say I will probably never put an industrial level of stress on the MG so my experience with basically 2/3 power may not be valid for what you plan to do with yours.

The box is smaller than the DTDP switch for my RPC and is simply screwed to the wall above the 220 outlet. I have a smaller box off to the side with the balancing capacitors. The hardest part was the wire gland provided wasn't big enough for the recommended wire gauge and I had to fool around getting the power into it. I didn't hardwire it, a cable to the receptacle, and twist lock receptacle to plug the Monarch into.

Apparently the person I purchased it from has had some bad experiences with Monarch owners who didn't know their motor HP is and the SPC he sells need to be matched to the HP closer than 3-5.
This company has been in business a long time and has pretty good sale going on. Might be worth a $100 lesson for your own experience:
 
I did, you coached me through adding them. Below is what I recorded. Next is to do it under a higher load, but to get there something to do first, or second, keeps cropping up.

  • 1x 40 μF between T1 and T3 plus 1x 40 μF between T2 and T3
    • L1 Amps max 77, steady @ 7
    • L2 Amps max 83, steady @ 7
    • L3 Amps max 18, steady 6
    • L1 - L2 Voltage 247, steady at 235v
    • L2 - L3 Voltage 223, momentary drop to 120, steady at 240
    • L3 - L1 Voltage 24, momentary drop to 0, climb to 120, steady at 237

OK. Honestly don't recall why I thought the MG aren't 5 HP. My MG manual doesn't list a motor HP, the WiaD manual I have lists 5 HP. I got a 4 - 8 SPC from eBay:
IIRC I paid less then the current listing.
 
On MG machines the DC spindle motor is 3HP, but the MG set is 4.6HP. WiaD machines were available with either 3 or 5HP DC spindle motors.
 
The static phase converter sounds very enticing, considering a solution is less than $200.

Thankfully I found a pretty good deal on a 10HP VFD for about the same cost. I plan on running it on the the OEM 3PH MG AC motor. I'll be purchasing an O-scope to measure the transient voltage spikes. If the voltage spikes are large, I'll install dv/dt filter on the loadside.

I'll post up part numbers, math and data once the project is successful. (I don't want to prematurely lay out specs, and put a bad solution in the wild)
 
If you're going the VFD route, you might want to look into using a shaft grounding ring. The high voltage transients from a VFD can find their way to ground by passing through the bearings and destroy the bearings over time. This is especially a problem on large motors (tens to hundreds of HP). Here are a couple of resources:
 
The static phase converter sounds very enticing, considering a solution is less than $200.

Thankfully I found a pretty good deal on a 10HP VFD for about the same cost. I plan on running it on the the OEM 3PH MG AC motor. I'll be purchasing an O-scope to measure the transient voltage spikes. If the voltage spikes are large, I'll install dv/dt filter on the loadside.

I'll post up part numbers, math and data once the project is successful. (I don't want to prematurely lay out specs, and put a bad solution in the wild)
Preventing VFD Induced Bearing Damage in Electric Motors
 
An ac servo motor is vastly better than anything dc, or anything vfd.
I had all in the past, so..

My 12x lathe with a 2.5 kW cont. ac servo motor has better torque than a haas st10, with 10 hp, and very much better continuous rpm/sf.
And it wont hard-crash breaking stuff, because the servo drive faults first.
In about 0.01 seconds (at 12 kHz).

Sure, an ac servo is expensive, about 1200€, and about 300-400€ for steel, mounts, HTD-30-8 pulleys (--128:24) belts etc.

Pros:
The extra torque is absolutely, amazingly, incredibly, wonderful and useful.
The seamless rpm 0-1000 rpm at chuck is excellent.
Cons:
Need to build heavy sturdy mounts in steel, buy big pulleys, $$, buy servo stuff $$.
 
....... I think you just don't understand how it works. The idler motor, in conjunction with the run capacitors, provides reactance to shift power from the two incoming legs to power the third phase. It's not like a separate motor/generator step.....

Not quite correct.
For residential 230v single phase supply,
the two incoming legs are 1 phase.
The RPC idler motor and run correction caps
provide 2 additional phases via the 3rd wire,
between it and the 2 incoming original single
phase supply wires.

-Doozer
 
  1. VFD on old OEM 3PH Motor
    1. Summary: Add VFD to OEM 3PH motor
    2. Cost: $1000
    3. Time: 1 weekend
    4. Pros:
      1. Not invasive to machine, no OEM parts removed.
      2. Minimal tuning/fiddling
      3. Low-ish start up inrush current
    5. Cons:
      1. Might burn out OEM 3 phase motor windings if no line filter is used

This is where I landed.....bought a single phase ~ 5HP 220 VAC VFD that did the job. Has not let me down thus far.

I am also concerned about running the old 3PH motor on a VFD and appropriately rated wire/winding insulation and concerns about voltage spikes. Luckily in my case the motor of the MG set was "gone through" in recent decades of which I do not have have any details but presumably it is in a better place than say an untouched example of the MG set.

I've been curious of of the filter.....I've talked to some EE's and they typically refer to a filter on the line side of a VFD but have also seen references of using a filter on the load side of the VFD to tamper these voltage spikes.

More details available on my thread or glad to weigh in with additional commentary as needed.

I see this thread gathered a bunch of feedback which is good that I haven't read through yet.

Brian
 
..

I've been curious of of the filter.....I've talked to some EE's and they typically refer to a filter on the line side of a VFD but have also seen references of using a filter on the load side of the VFD to tamper these voltage spikes.

.....

Brian
Line reactors on input sides of VFDs are recommended if you have more than one VFD on the same branch circuit.
Line reactors on the output sides of VFDs are recommended if you have more than 25 feet of wire (or so) between the output side of the VFD and the motor.

This information should be in your VFD owner's manual.

--Doozer
 
Hey all OP here,

I wanted to give a general status update.
I added a VFD to the OEM 3PH motor and added some DV/DT filters. It works very well so far!

I'll do a detailed write-up later in a new thread.

But adding the dv/dt filters massively reduced harmonics. The photo with the laptop screenshot. Left is with DV/DT filters attached, and right is without DV/DT filters.

Right now I'm trying to package all these components inside the machine. I'll also do another write-up on that once completed.
1708352899927.png
1708352928126.png
 








 
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