1955 Monarch 10EE

[tailstock4]

Here is some information on another VFD conversion that I believe may be similar to what you are considering for your 10EE conversion.

I had always wanted to convert my Pratt & Whitney to a VFD setup to help quieten the machine as the old contactors and two-speed motor were a bit noisier than I like. The Pratt & Whitney is otherwise a quiet machine and is even more so after the VFD conversion.

I did this conversion with the help and advice of Mark Jacobs. I chose to use a Black Max 5 hp because I really like the smooth, quiet performance of these motors. They also appear to deliver really good power at lower speeds and stay cool. I went with a Yasakawa 10 hp which makes the machine single or three-phase. I’ll let Mark tell you about the particulars and fine points of the drive and of the components used and why.

Another thing this conversion accomplished was to get rid of the piggyback electrical box off of the back of the machine keeping the machine looking original and reducing its footprint.

Mark did a really good job of sourcing the control switches which function and look very much like the originals. I run the machine from 30 to 90 hertz. This gives me a speed range of 7 RPM to 1,500 RPM with 18 speeds in the headstock.

This has always been one of my favorite machines and this setup just made it that much sweeter. Here are a few pictures of the conversion.

 

[markba633csi]

This is also a nice conversion by Deek:

10ee VFD Conversion

Hi All, I wasn't going to post my conversion, but my buddy talked me into it saying he thought it might help others facing the same issues. Here's my story... I've been wanting a 10ee for some time. Out here on the west coast they are few and far between. I haunted auctions, used equipment...

www.hobby-machinist.com

 

[RLHansen]

I rebuilt a 10EE for my brother replacing the tube circuit and DC motor with a 5 HP, Permanent Magnet, AC Motor and an appropriate VFD (230 3Phase input) to handle the PM motor. That rebuild went well. I did keep the back gear so the connection from the AC motor to the back gear transmission was a bit of a build out, mechanically.

I bought my own 10EE (which is 20 years newer than yours and looks 50 years older !!) and planned to convert it to an AC drive. I purchased a PM 5HP motor and a VFD. When I got the 10EE at my shop, I decided to tinker with the original electronics. It took me a few weeks, but I've replaced the tubes with solid state retrofits, bought the new style (PC board based) control box, replaced the field loss relay, cleaned all of the contactor contacts and she now runs beautifully. I suppose as long as I keep that AC motor and drive around, the fixed up DC circuit will continue to perform flawlessly. It took me a little while to get the max speed and IR Compensation set correctly, but with patience it's now fine.

I want to do a minor cleanup to the machine, a bit of sanding/filling and a new paint job. Problem is, the machine runs and performs so well I don't want to take it out of service for the cleanup job. Of course, I cleaned out all of the grunge and left over metal chips, cleaned all of the ways, taper attachment and changed out the cross slide nut so it's clean where it needs to be. Just could look prettier.

If there's any advice I can add, please reach out. It appears to me that there's allot more talent on this site than my meager work, but thought I'd share what I've done.

 

[MikeInOr]

Mark, I was hoping you would chime in, thank you.

I have 3 phase power available via a 15 hp RPC (currently feeds my LeBlond that the 10EE will replace) and/or could pull and new single phase feed if needed for the 10EE.

I am assuming my choice of incoming power dictates the the phase of the VFD, is that correct?

Is there any advantage of 3 phase vs. 1 phase power?

I am definitely keeping the back gear btw.

DEFINITELY wire the new VFD for 1 phase!

1) Your 15hp RPC does not produce true 3 balanced sinewave power legs with each leg 120 degrees apart from each other. The 3 power legs your RPC produces are not balanced and not 120 degrees apart. What the RPC produces is fine for running 3ph motors on 1ph. I have a 10hp RPC and have used it to power 3 phase motors for decades but it there is no advantage to using it to power a VFD.

2) A single phase only VFD is a rare beast. Almost all VFD's have a third input power lug for running the VFD on 3 phase. The only exceptions I can think of is 120v 1ph to 240v 3ph VFD's. The first thing any VFD does is convert the incoming 1-ph or 3-ph power to DC power. A 1 phase rectifier used 4 diodes. A 3 phase rectifier uses 6 diodes. Most all VFD's have 6 diode rectifiers of which only 4 diodes are used when running on 1 phase. A 3 phase rectifier will output considerably smoother DC power IF it is running on true balanced 3 phase power (NOT what your RPC puts out).

3) You can convert your 1 phase powered VFD to 3 phase input power by replacing the power cord with a 4 conductor power cord if it is ever deployed in a shop with true 3 phase power from the electric company.

4) Your RPC consumes power to keep the idler running. Running a VFD in 3 phase mode through your RPC is just wasting power with no benefits.

 

[Ultradog MN]

Welcome to the Monarch club.
I can't help with your new drive system as I'm electrically illiterate.
But threads like this make me grateful for my 12CK as most drive issues can be repaired with an axe

 

[jwmay]

I just wanted to say I love that picture with the forklift. Both of you look like you’re having a great time!

I have no advice. But it looks like you got a pretty nice machine!