Anybody have info on old Electro Craft motors?

Greetings all, I have googled and called the factory. The motors are too old. They were able to give me specs on one motor in the series but I'm pretty sure the voltage specs they gave me were wrong. The nameplate has this info: Model: E723 Part Number: 0723-08 013 Any help would be great. Thanks, Eric R Snow

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Eric R Snow
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Eric,

I have a '94 catalog that lists a few 0723-xx-xxx motors, but none with the same number as yours. And, unfortunately, if there's any sort of clue to the motor specs in the numbering system, I can't detect it. If you want a couple pages to look at and have a fax, contact me offline and I can send them to you.

On the other hand, it's easy to determine the voltage constant (V/krpm) experimentally, and once you have that you should be able to make a pretty good estimate of the other specs.

Ned Simmons

Reply to
Ned Simmons

Hey Eric Either email or call Rick Robison at A&D machinery (Wells Index). Most of the older Wells Index (Bandits) servo motor CNC'S used electrocraft servos. He keeps a pretty good supply of them on hand to service all the machines out there. They retrofit Centroid Controls and keep the old parts as spares. I've purchased two of these retrofitteed machines from them and am really happy with them and more importantly with their support.

Greg

pktubular.com

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Greg

greetings Ned, Thanks for the offer but I too have looked at pages from a catalog and there does not seem to be any way to interpolate my motor specs that way. However, it is easy to tell volts/rpm. Once I have that how do I figure out the amperage? Thanks, Eric

Reply to
Eric R Snow

Greetings Greg, I'll try that. These motors were originally installed on a lathe with a Bandit control. Thanks, Eric

Reply to
Eric R Snow

From scanning the catalog, it appears that 0723 completely specifies the motor frame size, so I wouldn't expect much difference in power output between various winding specs, unless you found the voltage constant to be wildly different from those in the catalog.

The voltage constant is 35.5 volts/krpm for the two motors I looked at in my catalog. Continuous current is 8.4A and peak is 42A, for torques of 400 and 2000 oz-in. For a different voltage constant, the current should be more or less inversely proportional. In other words, if you find your motor spins at 1000 RPM at 18 volts, continuous current would be around 17 amps.

Whatcha using the motor for?

Ned

Reply to
Ned Simmons

Greetings Ned, The motors were originally on a Cadillac NC lathe, 21 inch swing. They will either be used to put CNC on a manual lathe or for positioning a plasma torch. Both projects are starting to come together as far as a component list is concerned. The plan is to use Gecko Drive servo amps. These devices accept step and direction pulses from the control computer and drive servo motors. The servo motor position feedback goes to the Gecko Drive, not the control. So the loop is closed outside the control computer. This looks like it's the cheapest way to get a servo system that performs better than steppers. The plasma cutter system will need three servos, two for X and Y motion of the torch and the third for the Z axis torch motion. The lathe project goal is to turn a 14 inch swing lathe into a manual/cnc lathe. The software I'm going to use is Mach 3. The software writer told me that several folks have done the manual/cnc conversion using encoders to provide the motion commands for the control. The encoders are mounted to handwheels and are essentially Manual Pulse Generators (MPGs). But instead of using them to just jog the machine during setup and the like they are also used just the same as the handwheels are on a manual machine. One difference though is that the MPGs have detents in them so that each move is an exact multiple of the smalles move the machine can make. When used as handwheels there is just drag without detents. Cheers, Eric

Reply to
Eric R Snow

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