Surplus Drill Press Question

[W2VW]

Spending a few weeks finishing a remodel of a high school. Fringe benifits you know.
All metal shop equipment available for a song. So, now have a really nice bench grinder and cast iron pedestal. Also grabbed one of those giant drill presses. The thing has got to weigh at least 350 Lbs. Either that or I am getting old (nah). The other vultures passed it by because it is 3 phase. The question to you metalwork veterans is would it pay to use a DC motor with a speed controller like this? I have a good size DC motor here in the pile.

http://cgi.ebay.com/Motor-Variable-Speed-Control-AC-DC-120v-AC-15-Amps-New_W0QQitemZ7541781241QQcategoryZ42920QQrdZ1QQcmdZViewItem

OR should I just use the existing 3 phase motor on 1 phase with a starting cap at reduced power?

My current drill press is one of those Home Depot Asain jobs. It's OK but there is not enough distance from the center of the bit to the post and it is petty weak.  I don't have a lot of time on these machines and need a few words from someone who has.


To rephrase the question. Would there be an advantage to speed control of the drill press similar to a sewing machine?

[Glenn NY4NC]

Only that yer supposed to drill aluminum at slow speed, and steel at high speed..

To rephrase the question. Would there be an advantage to speed control of the drill press similar to a sewing machine?

[W3SLK]

Dave, If I recall, the third phase is used only to get the motor up to rated RPM. There is a device called a ROTAX(?) that you can use to create a third phase for the initial 'UMPHHH'. After that, you are on the the other legs. Check out Grainger. If memory serves me, they are about $350. When I was still talking to him, (I can never seem to get back in touch with him) Huey, KD3U was using them in his shack to run an engine lathe, and vertical mill. I'm pretty sure I right about this but check with the other electrical guru's on site. G'd luck.

[BillR]

Suggestion…..

If you want to go the DC route try the following:
Minarik – Motor Master 20000 Series
Model – MM23101C
Input 115 (230)v ~ 1Ph 8A
Output Armature 0 – 90v DC (0 – 180)v DC
Field 50/100 1A
We use a few of these on our drill presses here in the shop. They work pretty good for single phase or three phase set ups.

73
Bill
Lancaster, Ma

[W2VW]

Thanks for the ideas. I'm going DC to match my initials. To heck with 3 phase motor generator and that stuff. I'd do that if there were more 3 phase motors in the shop but there ain't. Going to try a Variac into a rectifier block into a surplus commercial treadmill motor first. "Jane, stop this crazy thing".

[WA1GFZ]

Dave make sure the DC motor is properly fused so it doesn't get fried if it stalls. I worked on computer controlled machines with DC motors and A.B.
speed controls. I've seen guys blow beautiful motors by stalling them. One clown installed bigger breakers rather than fix mechanical problems. Blew a new motor with gear box. The motor sits in one spot and that section of the winding over heats until the insulation breaks down.

[W2VW]

Thanks for the heads up Frank. Lotsa talent in this bunch.