[triberman]

I'm wondering if anyone used these motors off ebay? A 3/8 shaft worries me, seems a little puny...

I'm retrofitting a bport

Reliance Electric DC Servo motor
NEMA 34 Frame
Model 0690
Back EMF Constant, ke = 62 V/kRPM
Torque Constant, kt = 5.5 lb-In/Amp
At just 10 amps, that's 55 Lb-In = 880 Oz-In.
Nominal Speed Rating: 1750 RPM
Nominal Voltage Rating: 120 Volts
Continuous Current Rating: 4 Amps
Peak Current: 20 Amps
Continuous Power Rating: 1/2 H.P.
Motor Body Diameter: 3.38"
Motor Body Length: 9.0"
Shaft Diameter: 0.375" x 1.13" Long
Integral Encoder: Agilent P/N HEDS 5605#A06
500 Line yielding 2000 Counts/Rev.
Encoder is mounted under protective steel cover on tail end of motor.

Also says:
*** THESE WORK WELL WITH GECKO DRIVES.
The lower voltage rating of the Gecko is not a problem:
With an 80 volt supply, you can expect
~1750 RPM
~1100 Oz-In peak Torque

Thanks !

[murphy625]

My very first servo was a reliance electric..

They have really good customer service.. Even when I told the guy I had bought it off ebay they faxed me everything I wanted and spent some time on the phone answering questions when I had them..

Murphy

[lerman]

I'm using the same motors for my Bridgeport clone.

I cut my first metal yesterday. -- or more precisely, melted my first aluminum.

I understand your concern with the 3/8 inch shafts. The first thing I did was mill some flats on them so I could lock the pulleys to them with a set screw. I turned some adapters from the 3/8 inch shafts to the 5/8 inch pulleys that came with my X, Y, and Z axis kits (from Elrod).

Ken

[triberman]

Hmmm... I guess your ok since you can still type?

Please let me know how they work, and good luck!

[triberman]

How are the servo's performing lerman? :stickpoke

[lerman]

How are the servo's performing lerman? :stickpoke

You can call me Ken.

I just got back from a wedding in Chicago (which ran from Friday to Monday). So I haven't had a chance to try again. I did order some HSS mills from McMaster Carr that are made for aluminum. They should arrive today. I'm trying to avoid using coolant because of the mess.

Ken

[triberman]

Ken,

Sounds like my wife's family weddings.

Putnam makes ok HSS aluminum cutting endmills, available from msc.

[lerman]

How are the servo's performing lerman? :stickpoke

Just cut some metal. Milled a 2.130 diameter pocket 1/2 inch deep and milled a 6 pitch jar thread. It seems to be just fine, although I seem to have some deflection in my Y axis -- probably caused by not torquing the bolts holding the yoke tightly enough. (The Y diameter is about 10 mils undersized.) It is possible that the Y axis could use a little stiffer tuning. I've set it so that I will fault with a 5 mil following error. If I had just under that (not likely), it would account for most of my error in diameter.

I measure about 1.5 mils of backlash on the Y axis and less than .5 mill on the X axis. The finish seems pretty good.

I need to get a chip guard for my keyboard and protect some of the cables a little better.

All and all, I'm quite satisfied with the performance (for a first cut). I expect to get it much better.

Ken

[roonster71]

I just put those same servos on my excello 602 mill with a ruttex r990h controller using 85vdc so far there awsome you should make flats on the shaft to secure your pully though,