New Boss Retrofit Questions

[tcalef]

I've been reading as much as possible, and have some questions before I start this process. First off, I have a Boss IV cnc, where all the steppers and controls work, the machine is in really good condition. My aim is to get this machine running with Mach3 for hobby milling (no plans on servos)

1) I've ordered a 5hp rotary phase converter, but it looks like VFD may be the way to go. On eBay, the VFD's look like $200, so I think I could get one of those and 3 drives for the same cost of the RPC.

2) It looks like most people build their own power supply to give the steppers the right DC voltage. What voltage are the stock steppers supposed to run at? I am assuming that the power supply needs to convert 220 VAC to that voltage, but at what current?

In the end it looks like new drives are more recommended, but from a system approach, is it better off with a RPC or should I switch the incoming power to 220 and run the spindle off of the VFD?

Thanks,
Tom

[sdeering]

I think the stock steppers ran around 50v
I run mine at 70v it depends on what you go with for drives.
Look for a big toroid transformer for the PS. I found one at a motor rewind shop I think it was out of a big Batt charger. I removed the secondary and added wraps till I got the voltage I wanted. Add caps and a rectifyer and thats your power supply. Oh and 110 works. I think 500va is what I read for the origional supply.
Campell breakout board.

Make sure you use shielded wiring for most of the control and ground one end. They can be prone to EMF causing all sorts of anomolies.

As for spindle power I run a home made RPC. I would go with a vfd if you are purchasing. However its nice to have the RPC if you see a 3phase piece of equipment go for cheep.

Good luck, the retro is the way to bring new life to these old mills.

[panchula]

The original steppers on my Boss 5 were Sigmas on the X & Y and a Superior on the Z. The factory controller ran them at 56V. I used an Antek 48V toroidal followed by a PMDX -135 power conditioner good for 20 amps at 80V. I rewired the steppers to to a serial configuration and powered them with Gecko 203Vs. PC control is via the parallel port and a CNC4PC C-11G board. The spindle is powered by a TB Woods VFD. I ran a two pair shielded wire to the factory limit switches and used one pair for the home using the NO connections for home, and the NC connections in serial to all the switches for limits. On the Z axis there are three switches from the factory, only use two for limit.

Mach3 or EMC for motion control, your choice.

-Mike