Clausing 5914 VFD

[machPete99]

I did this a while back, but figured I'd post the info for others that might be interested.

This setup completely replaces the original Reeves drive and countershaft arrangement. The motor is the original Doerr 2HP 3PH unit. I am using the stock cogged belt size/length, but have fitted the motor with a slightly smaller drive pulley (22T). I redrilled the motor support brackets so they could use the slots previously used for the countershaft support. A piece of 1/2" steel plate is used to get the motor in the correct location, in line with the spindle pulley.

Mechanical parts, from McMaster-Carr:
6495K615 - H Series Quick Disconnect Timing Pulley (1-1/2" wide H series Quick Disconnect 22T)
6086K34 - Quick Disconnect SD 7/8" ID 3/16" keyway
6484K284 - H Series 63" x 1-1/2" Belt (630H150)
99020A420 - 3/16" key stock

VFD is Hitachi WJ200-022SF, from Drive Warehouse. I am using 4 x 50 ohm 100 watt resistors (in series/parallel pairs for 100 ohm total) for braking. Most of the control items are from Automation Direct. The enclosure is good sized (14 x 12 x 8), from factorymation, so does not need a separate fan. I am using a (2) pole motor switch as a disconnect, relatively simple control wiring. The original motor flexible conduit has been rerouted to enter the enclosure, near the top. Everything is mounted to a an aluminum plate which can be removed for service.

The speed control is pricey but industrial quality (Allied: Honeywell 53C11K + Schneider Electric ZB4BD922). The control panel is located where you stand so you can change speed etc. while machining.

Pete

 

[wa5cab]

Another member here inherited a 6900 Series on which he says the variable speed drive had been disabled and a VFD added, possibly with the original motor. He hasn't taken any photographs yet so I don't know exactly what was done to it. It is difficult to judge from your one photo how high your motor is off of the floor. Is it located approximately where the countershaft once was? Maybe that's what was done to his.

Over what motor RPM range (slowest to fastest) do you run the motor? And whatever the slowest speed is, have you noticed any tendency to overheat after running for an hour or more at that speed?

 

[machPete99]

The top of the 1/2" motor mounting plate (bottom of motor flange) measures about 15-1/4" from the bottom of the housing.
Motor centerline is approximately at the centerline where the countershaft would be. Its actually slightly lower due to the slightly smaller pulley.

From my calculations, speed range is similar to what the Reeves would do, if allowing motor to go from 24-120 Hz (696 - 3480 RPM):
Direct drive: 388 - 1940 RPM, Back Gears: 55 - 277 RPM

Any slow turning I tend to use the back gear mode, so motor is turning relatively fast. I have not seen any overheating issues. The only issue I have is that using too much brake at higher speeds with a large (8") chuck can cause the control to kick out. My "brake" knob simply changes the braking constant for quicker stops, but needs to be used at lower speeds. All of these settings are adjustable on this VFD.

I was able to drill 1" holes in a couple 3/8" thick steal disks recently without any trouble (in back gear), no shortage of torque for "normal" tasks. This VFD does have some special settings ("Sensorless Vector", "Torque Boost") that are supposed to produce more torque at lower RPMs, and I do have them enabled.

The "Jog" mode is really the same as setting the motor to a slow, fixed speed (currently 6 Hz or 174 motor RPM, 14 backgear spindle RPM). Its probably best for things like powered tapping, but I have not used it yet. You probably don't want to run at that speed continuously.

You can reverse the motor while running, although it goes through standard deceleration and acceleration rampings.

 

[wa5cab]

OK. That sounds encouraging.

What size is the 5914?

 

[machPete99]

The 5914 can swing 12" over the carriage, 36" between centers, weighs about 1100 pounds or so (maybe less now, without the countershaft stuff). Spindle has 1-3/8" bore, can take 5c collets with proper adapter sleeve. Ways are hardened on this lathe, cannot detect discernible wear on mine.

Mine is mid 70s vintage. I had to replace bearings in the motor, back gear (drive hub) and quick change gearbox. Everything else is just cleaned up a bit. The countershaft clutch mechanism has at least one oddball bearing that you might not be able to easily find. I did have to make sleeves for some of the bearings as current sizes differ on the ID a bit.

 

[wa5cab]

OK. What's the swing over the bed, and the nominal distance between centers?

 

[chips&more]

How smooth running is the new conversion? Are you getting any noise in the finish of your cuts? Do you miss the clutch?

 

[machPete99]

I did not run the lathe much in its original configuration, except at the shop that I bought it from, so cannot compare much on finish. The lathe seems to run very smooth, especially in direct drive. It is also much quieter now; the Reeves setup made a lot of rumbling noise. There is a small amount of whine from the VFD but not objectionable. Noise now is predominately from the gear train, when in back gear, or running the lead screw. I ended up adjusting the banjo position for better engagement and that also quieted things down a bit. I would not have been able to hear that issue over the Reeves rumble.

The VFD has electronic braking which I think is similar to the mechanical clutch/brake capability, and you can also adjust it, within some amount of reason. I don't really miss the original clutch, and it had some issues (would not stay engaged). It might have been nice to rig a another stop switch to the original clutch/brake lever but I did not bother (at least yet). Having the handle at the carriage is a nice feature, but I arranged to have the control buttons in close proximity.

Being able to change speed in the middle of a cut is a nice feature. You can dial in the color of the chips. The original Reeves control on this lathe is not really in a very good location.

 

[machPete99]

Attached is a recent project, flanges for a tractor loader support. These were made from DOM tubing, OD turned down, and CRS flanges, tigged on and then trued up on the lathe. I think this was all using HHS tooling (MO Max), in back gear. Finish was not super important, so probably cut a bit aggressively. No noise in the cut here, and these are tough materials. The pits on one of the flanges is the weld area.

 

[Dhector]

Another member here inherited a 6900 Series on which he says the variable speed drive had been disabled and a VFD added, possibly with the original motor. He hasn't taken any photographs yet so I don't know exactly what was done to it. It is difficult to judge from your one photo how high your motor is off of the floor. Is it located approximately where the countershaft once was? Maybe that's what was done to his.

Over what motor RPM range (slowest to fastest) do you run the motor? And whatever the slowest speed is, have you noticed any tendency to overheat after running for an hour or more at that speed?

If I am the member your referring to I have a pic n this thread page 2.

I like the setup you have there. Looks like it could get rid of a lot of wear spots like I have.
http://www.hobby-machinist.com/threads/new-clausing-6913-gear-box-engagement-lever-fixed.