Newbie- Series I power supply

[marvfrankel]

I just bought a Series I CNC mill, and would like to use the existing steppers and transformers, using Gecko 203's for drivers. Has anyone done a similar conversion? I'd appreciate any advice or photos of this installation.

[DSE]

I'm going to use the T1 transformer (the 110VAC supply, not the huge 3phase one) from my boss 5 to power the 203v's. I've wired the transformer for 240VAC but will be applying only 120VAC. This gets me about 54VAC/76VDC out. Does anybody know what the KVA is for the T1 transformer?
Here's some number crunching and a diagram of my T1 Transformer:

[jholland1]

The BP Boss series mills are very power hungry tools for their spindle horsepower. These machines were designed in 1970's and for the step motor series consumed huge amounts of power at rest. Many of mills which are still operating have been converted to servo motor axis drive. The Superior or Sigma factory issue step motor is capable of enhanced performance with greatly decreased power consumption by updating to a modern drive.
The T1 transformer in the lower righthand area of the power cabinet is 1KVA rated or just under one KW. It will work just fine as 55 to 60 volt ac power provider. If you view the photos in my link you will see most factory components totally missing. The control cabinet is stripped bare and self contained D6 Superior drives are present. I have tested many step drives in these machines and Gecko 200 series would be a great choice. All Boss 3 thru 6 series machines are over 25 years old. For this reason on a conversion I recommend total removal of all factory components. BP devoted one 25 amp bridge rectifier per axis drive. Modern drives with proper capacitance and current density supplied by beefy transformer should do well with one 35 amp bridge rectifier supplying x,y,z axes. The factory capacitors have seen many thousands of hours on time. Frequently they have a dirty power profile even if they do not qualify as undergone outright failure. Replace them with fresh dc caps. Usually 7000 microfarad per axis. Fuse protect every circut!
I will have more comments on Boss power later today.

http://good-times.webshots.com/album/562537950DZgVGE

jh

[jholland1]

A frustration on a Boss mill with a malfunction is the number of control relays which may be a source of concern-either with internal malfunction or a metal chip on external junction, loose wire, etc. Two reed relays are usually present in the transformer cabinet. CR3 and CR5. The operating coil on both is 24 volts dc power. The upper relay is a 12 pin CR5. The lower relay is 8 pin CR3. Both are necessary if the original control boards are in use. Once the Boss system is not used both relays are not needed. Some functions are not possible -automatic spindle shut off. Quill retract decel is a board function which is lost as well. If you look at images on my photo link you will see a greatly simplified wiring arrangement in the transformer cabinet. CR 3 and 5 are removed. The air cylinder brake works as manual on-off only. No automatic brake when spindle in shut off. The air speed set works fine without relay. The spindle off-on works fine without relay. This switch has 120 volt current running thru it. The e-stop switch has both 120 volt ac and 24 volt dc power. The solenoid coils controlling spindle speed and brake are all 24 volt dc. The spindle motor starter has 120 volt ac coils with self holding function.
Control relay 4 is present in some machines. It largely relates to flood coolant power circut. This is a solid state triac relay with 24 vdc off-on input power.
Control relay 1 is a 24 volt reed relay in the control cabinet. It largely functions to coordinate limit switch, system reset, e-stop. CR 2 is a 12 volt dc reed relay which ties directly to Boss boards.
Both CR1 and 2 may be removed. Some mechanism must be in place to protect machine from over travel if it continues as cnc. Manual use may omit relays. Pretty much all operating systems for pc control (Mach 3, etc) have input for limit switches. A breakout board is usually needed. This allows limit switch protection of machine in cnc mode.
When the machine is configured as my images show the cooling fans are not needed. Energy is saved and the machine becomes very quiet.
http://good-times.webshots.com/album/562537950DZgVGE

jh

[marvfrankel]

Jackson,
Thanks for the very comprehensive explanation of your conversion, and the photos you posted. I have my choice of phase converters. I have a rotary converter, and a VFD that I've been using on my manual mill for the past 2 years. The VFD gives me speed control with a built-in brake, but the Bridgeport has such a wide speed range available, that the only advantage that the VFD would have, is to allow me to start & stop the spindle through the Mach3 software.
If I can condense the controls enough, I'd like to have enough space to include a PC that I built to control a Sherline CNC conversion that I did last year. It runs XP Pro, and I kept it very clean by only loading Mach3 in it. I'll try to document and photograph my conversion, so you can follow my progress.

Thanks again,
Marv Frankel
Los Angeles

[jholland1]

Hello Marv
The most elegant BP Boss upgrade I have encountered was on a series II Boss 6. The Reeves vari-sheave drive which was factory was replaced with Goodyear Pd herringbone sprocket and rubber drive belt. This eliminated a lot of rotating mass and improved surface finish. Machine was almost silent. This upgrade required installation of Hitachi vfd and brake. It also permitted single phase power. I will be installing vfd in a few days on machine in photos.

regards
jackson

[marvfrankel]

Jackson,
For the time being, I think I'll use the speed changer as it is, until I get to know what I'm doing. Are you controlling the speed with the VFD dial, or do you have relays connected to the VFD? I looked at an exploded drawing of the speed changer. Which of the parts did you replace with the herringbone drive?
I'll wire up a Phase-A-Matic rotary phase converter, because one of these can run both my manual mill, and the Bridgeport. I'm keeping the manual mill running, in case there are parts & pieces I have to machine. Then, I'll think about selling it. My half of the garage is quickly becoming my two-thirds. What part of the country are you in?

Marv

[jholland1]

Marv
I am half way between Seattle and Portland. I am running the mill with factory controls on front panel. All Boss machines came with vari-speed. The v-ram Boss had conventional hand crank 2-J head for speed change. The rigid ram usually had a GAST air motor which operated vari-sheave drive. Replacing the vari-sheave with frequency drive and herringbone sprocket really makes sense only for high end surface finish job shop. Hobbist usually are better off with factory hardware. This includes me. I have 12 BP Boss machines in stock but I do not perform contract machining. I am a collector and occasional seller. The primary reason for frequency drive dedicated to one machine is to utilize single phase power. This avoids the annoying noise from roto-phase running all day. Saves on power consumption as well.
jackson

[DSE]

I'm going to use a VFD to control my spindle. Marv, it sounds you may be at the same point I am with the conversion. I have a manual step pulley machine that the VFD drive is currently hooked up too, and so the VFD will be that last thing to hook up on the cnc spindle. Because of the step pulley on the old machine, I have a potentiometer conected to the VFD to control spindle speed. My plan for the cnc will be to initially use relays to turn the VFD Fwd/Rev/off through mach3 with manual overide. Later on on I will hook up speed control to Mach3 using something like this http://www.cncathome.com/vfd.html, or go with a comercial board.

For the manual mill during this evolution I may piggy-back power from the VFD until I get a phase converter built or sell the machine. I would only be using be using one machine or the other on the VFD, not both simulataneously (its rated for 3hp, 3phase).

jholland1, great info. That really clears up a lot of questions regarding what to use from the old boss hardware. I was hoping to use those relays to switch the VFD with the campbell bob, but since they are activated with 24VDC not 12VDC, I don't think this will be possible.

One of the challenges I'm dealing with on the conversion right now is setting up an ESTOP circuit. I'm not sure what the best setup for this woulds be. Anybody have suggestions?

[jholland1]

DSE & Marv
I installed a vfd today on machine in album link. Will have pics tomorrow. All works great but I am using vfd at fixed 60 HZ frequency and varispeed sheave drive. I no longer need rotophase. 220 single phase in. 5 hp vfd.
One critical point. Do not design system that utilizes any power from vfd for control of switching device. This includes relays, holding coils, solenoids. Today I initially ran vfd output power thru motor starter. Burned up reverse coil in about 2 minutes.
jh