I spoke to JT yesterday and he is preparing some possible upgrades for all the machines. One is a DC drive system to replace the AC motors and all the belt mechanisms for changing speeds. Another is a stepper driven power feed unit that can cut threads and upgrade all the old machines to 3 axis power feed.
I went ahead and ordered the DC system for my Patriot. I got the controller, switches and speed pots by mail in 2 days. The motors should arrive next week. JT also sent me an instruction file on how to drill the new mounting holes for the motors. He included the drill and tap as well. Today I plan to work on mounting the control board and the other controls. I removed all the old belt change stuff, and let me tell you, its about 75# worth of mechanism that you no longer need. Attached are some pictures of the progress so far. Once the motors arrive I will post the mounting and how it all works.
The problem with DC motors are that they are expensive and heavy. Three phase motors with a VFD drive are very light cheap by comparison. The VFD drive is the expense. Unless you are threading something which you don't do very often it has no benefit above 500 rpm.
Your using the same control I'm using on mine I see. Recommend adding some kind of air flow(fan) to cool the controller. (I used 2 35mm 12volt dc fans) Gets hot on long run time. Also if your using the same motor as I did. Recommend adding some kind of fan to that. I'm using a 120mm 120cfm 110ac fan. These motors weren't designed to run for long periods with out some time of cooling.
Thanks- According to the instructions, there are 2 cooling fans in the set- 1 for each motor, but no mention of a fan for the control board. The patriot has 2 mounting holes in the housing for fans, so maybe I will get some for the board as well. I'm anxious to get the set up and running, what is your opinion of the torque etc on these drives.
They have plenty of power. Keep in mind they don't like get wet. I'm only running the mill with dc motor. Don't use the lathe on mine often enough to justify a dc motor.
A couple of changes in my program. On the advice of some other shoptask owners, I decided to go with the Minarik controller. It has a lot of features including dynamic braking and can run off 220 volt power. I ordered 1 controller and will run it on 220 volts and pull a 110 leg off that to run the original controller. After I compare the performance I can decide whether to go with 2 Minariks. On your advice I also ordered a couple of cooling fans for the CNC housing. The patriot has 2 mounting places already in the housing for cooling of the CNC and I found 2 fans for 7.00 each that fit. I got my motors and other fans yesterday. The motors came with pulleys installed - 2" for the lathe and 2.5" for the mill. They bolted up in a snap. Got them mounted and belts installed and adjusted. I also followed the wiring diagram JT sent me and have the DC wires using spade connectors and the 110 volt wires using bullet connectors so there is no chance of mixing them up. The motors are USA made and are surprisingly small, but rated at 2.25 HP . They also have a thermal overload switch. Today's plan is to get the motor cooling fans mounted.
A couple more pictures
I did a little more last night and this morning. I though about a number of options for the fan mounting. I wanted them to blow past the pulley through the motor to help keep stuff from being pulled into the open end. I don't think the mill is any real problem because it sits vertical and well above any cutting. The lathe would be subject to chips and fluids from a coolant system, so I plan to make up a cover for it as well. Anyhow, after some looking and pondering, I decided to mount the mill fan inside the top cover just over the motor end. There is just enough room to clear all the mechanisms. On the lathe I decided to put the fan on the door. I wavered around a bit because both places required cutting a hole in the parts and its a new machine. Finally I kicked myself into gear and layed out the holes and used a 4" hole saw to cut the holes. Mounted the fans and ran the wires and tested out the openng and closing of the covers. Everything works and fits nicely. Watch out though- the hole saw makes a razor sharp edge on the sheet metal and I now have a nice band aid on my finger to prove it.
Kicked around the idea of a lathe motor shield for a while and tried to make one out of some old sheet metal. I don't have a shear or break, so I was bending the stuff over the edge of the bench and rivetting the corners together- by the time I finished it look like c*ap. Then I noticed the CNC drive cover for the Z axis was almost identical to what I was making. I pulled it off and it fit like a glove- all I needed to do was drill 2 holes. JT said he had one in stock and the price was cheap, so he is sending one to replace mine. I drilled it out and sprayed it black to match the motor mount. I just need to get a rubber grommet to plug the hole where the acme screw goes through.
A further update on the controllers- I ran the motors- one off the original controller and one off the Minarik. I can't tell too much difference without some sort of dynamometer test, but I feel the Minarik is putting out more torque. This may be due to the fact that it has the load compensation adjustment. I am going to order one more before buttoning the whole thing up.