Thought I would add a few comments about Jake's 1440GT VFD/System install, we went with Yaskawa's new GA series VFDs which come in a GA500 which is a basic display or the GA800 with a full LCD display. The model chosen was their single phase input GA50UB012ABA which can output up to 12A in ND and 11A in HD (150% output for up to 1 minute). I have been using the Yaskawa GA500 in a number of my recent builds, they have a few more features than the Hitachi WJ200, and the software interface is much better. They are significantly larger than the WJ200, so that must be factored into the unit's mounting. I have attached a parameter file for this build/motor, a few things that differ from the WJ200 is the JOG FOR/REV are separate inputs and there is a separate programmed emergency stop input. The control system differs a bit from my previous designs for this particular VFD, I still use a multiple relay design because of reliability, lack of electrical interference issues and cost. Typically there are 3 levels of redundancy in the system, so some functions like JOG can only per operated in the stop mode. The coolant circuit operates either with just spindle rotation or continuous, and in this build has the option for 240VAC single phase and/or 24VDC for a solenoid(s). The proximity sensor's I use are triple sensing and are made to be flush mounted. They have a lifetime warranty, but if they failed the system stops and there is a separate limit switch in addition to the hard micrometer stop. The repeatability of the stopping position is usually less than 0.001" and allows threading up to around 600 RPM depending on the thread pitch.
The Marathon BlackMax Y541A was definitely a tight fit, they hold very tight RPM regulation over a wider speed range with sensorless vector control. Normally I would recommend the Marathon 3HP E470 XRI motor, which is a bit shorter it is just in this case the Y5451A was less expensive (and the "A" model just fit). Most 3HP 3 phase 4 pole motors run in the 8-9A range. The inverter/vector motors tend to run with a bit less current then standard motors, and vector must be run off of a VFD. The E470 is an excellent replacement motor for the 1440GT, BUT either of these motors requires a new motor horizontal motor mount and some metal cutting for clearance. Since the cabinets are very rigid, a simpler approach for the belt tension is the single turn buckle under the motor to the headstock cabinet that Jake made. Looks mighty substantial.
On the 1440GT I typically put the speed control in the RPM housing and use a MilSpec. 3 turn 5K linear pot which gives very fine speed control, the pots are wire-wound and rated for millions of turns. In years past I offered a RPM/SFM option, but the MachTach is no longer made and I find very few people use the SFM calculator. There is the Tachulator, but seems like the only US distributor has suspended sales.
Nice install on the tailstock DRO, very clean approach.
Testing the control board
A Marathon E470 motor install with AX29 belts, the Y541A install of Jake's used AX30 belts.
