On 7/27/2021 1:43 PM, Gene Heskett wrote:
Actually, the torque goes up as the speed goes down, because they run at
the speed determined by the counter emf generated by varying the current
in the field winding, and the higher current actually causes it to slow
down, but at the same time, the torque rises because the field magnets
get stronger, generating the balancing back emf at a lower armature
speed. Unfortunately for those motors, the non-grain oriented steel used
in those motors is saturated magnetically, at around 1/4 of the magnetic
field we can make with todays magnetic materiel. Not very efficient and
it shows in the power bill to run it.
My bet is that since this is a very old tech, the power supply will have
both selenium rectifiers and wet electrolyte filter capacitors, and one,
or the other or both have reached their retirement age, like me a long
time back, and like me, are no longer working very well.
Where are your digs located Earl? I am in north central WV.
**Earl Weaver
Email: [email protected] <mailto:[email protected]>
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Cheers, Gene Heskett
Gene,
Yes, this is an approx. 1984 machine.
I suspect the drive has seen it's better days. The lathe comes out of a
tech school, hasn't been used much. Probably sat unused for "years?"
I converted it from an old Fanuc controller to LinuxCNC.
Is there a good option for replacing the DC Drive and using the existing
DC Motor, or am I better off changing to AC VFD?
I'm located up here in central Wisconsin, moved here in 2008 from
Pennsylvania.
I've been through West Virginia already. Mountainous? I still like the
mountains out east!
**Earl Weaver
Email: [email protected] <mailto:[email protected]>
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