single phase spindle motor

[Don Lester]

I have a series 1 step pulley machine with a three phase motor on it which I drive with a rotary phase converter. I would like to eliminate all that BS and retro fit a single phase motor on the machine. There are 2hp single phase 220v heavy duty motors available, some even have 1.125" shafts such as a Dayton #4K813- $325. I realize that you would have to make all the mounting hardware or piggy-back it on top of the existing Fairbanks-Morse motor. I'm assumeing this motor can operate vertically, but I don't know that for sure. Does anyone have any experience with such a project or have any idea as to why it wouldn't work. Thanks.....Don

[machintek]

Bridgeport did sell a single phase motor for the step pulley head but it was VERY expensive.
I have seen these converted to a direct belt drive and a variable frequency drive and motor fitted as well. Many choices.
Just search the trends posted.

George

[NEATman]

http://web6.automationdirect.com/adc/Shopping/Catalog/AC_Drives_-z-_Motors/GS1_(120_-z-_230_VAC_V-z-Hz_Control)/GS1-21P0

Keep your existing motor. Single phase in, 3 phase out, makes the motor variable speed for $125.

NEATman

[UKRobotics]

I agree with NEATman, VFD all the way, it really is the best solution.

[Don Lester]

thanks "neatman" for your input ,but unfortunately I could not access the web site you suggested and I don't understand what you mean " single phase in, three phase out ". I have installed a three phase variable frequency drive made by Dayton, which in my mind has reduced the max amount of power available to the spindle motor even more than the rotary phase converter has, so the stock 1hp Fairbanks-Morse motor seems to be producing now only about 1/3 or 1/2 hp. I can EASILY stop the spindle with the manual brake while the power is on ! I haven't checked the total current draw with all this stuff working but my feeling is I'm not getting anywhere close to the amount of spindle HP I'm paying for. Plus, the variable frequency controller screws up my radio reception so bad that I can't listen to the ball game while working in my shop. I have operated this machine before with real three phase power, so I know what it should be. I can't help thinking that a 1-1/2 or 2 Hp single phase motor wouldn't be a lot better.

[Don Lester]

Neatman I finally got through to the web site you suggested and I know what you mean. In your experience does this devise give you good HP to the motor ?

[NEATman]

Don-
I have a BPT with a 2 HP cont. 3HP intermittent motor with a 5hp VFD connected. I do get full power from the head, but the VFD that I have is intended for 3 phase, so I had to oversize it and de-rate it to get full power at the motor. It is my understanding that the units that are rated for 1 or 3 phase input are "oversized" already, and should provide full power to your motor at 60Hz. I have not purchased this particular unit, but I have heard others on this site who have.

http://www.cnczone.com/forums/showth...omation+direct

You can also do a search here on cnczone for automation direct and read what other people have posted.

Neatman

[tim-tbl]

Cant you just take the motor off and have it rewound to a 220v single phase?

[Cartesian-xyz]

Don, If your BP seems to be gutless then pull the cover and check the wiring on the motor. If you are supplying 220v and the motor is wired 440v, it will be gutlesss!!! This
happend to me. I bought a BP from a shop I know was'nt 440v but when I got it in my
shop and wired it up it was painfully underpowered. When I rewired it 220v, OH YA.
I currently have a Sumitoma frequency inverter hooked up to mine and I think this
is the BEST way to go. I rarely ever move my step pulley from the 1750 RPM setting,
just dail back the RPM with a reostat.
Stephen, Cartesian Machine Works

[Don Lester]

The VFD I've installed is between the rotary phase converter and the spindle motor. The motor is correctly wired for 220v. Prior to installing the VFD the motor power was adequate, but not as good as real three phase power. When I installed the VFD I noticed a significant loss in motor torque, so much so that if I lower the RPM very much the spindle has very little power. It would seem to me that the VFD is not happy getting power from the rotary phase converter. The VFD I have is quite expensive from Dayton ( $700 +). It's rated at 2 to 7 HP-- three phase input, no mention of single phase. Could this unit be powered directly by 220v single phase and produce 220v three phase for 1 to 2 motor HP like some of the other units mentioned here, there by eliminating the rotary phase converter completely ?

[Cartesian-xyz]

Don,
Yes, the VFD I mentioned hooked up to my BP is 1ph in and 3ph out rated to a maximum of 3 hp. I have a 1 hp motor on the BP. This type of VFD is inexspensive ($150-$300) and far less hassle than a roto-phase.
It is note worthy that these small inexspensive VFD have no encoder feedback and
are not constant torque rated!
Stephen, Cartesian Machine Works

[vmax549]

Don here is what I did. Bought a 2hp c face motor bolted it to a 1/2" thick alum plate. Turned an extention shaft that slipped over the stock shaft and made it the same length and dia as the stock BP motor. Set it in place adjusted the belt and it has been working fine for about 10 years now, I run it every day. No hassles or radio interference,works great for a manual mill.
Now my BP boss CNC I used a 3hp VFD to drive the stock 2HP motor. That works great for a CNC application when CNC variable speeds are needed. Sheild ALL the VFD power cables and noise is not an issue. May need to sheild the VFD also. Installed a fan to help cool the motor when running at slow speeds for a long time. TP (:-)