3881
General Mach Discussion / Re: CS Labs CSMIO/P-A
« on: August 08, 2018, 03:45:26 AM »
Hi,
what are you trying to achieve? If I understand correctly you have a working three phase asynchronous spindle motor of 5kW.
Is that correct?
What are you hoping to achieve by replacing it? You mentioned the desirability of having it operate from a single phase supply.
Hood and I chimed in and we agree that the potential for a single phase servo is in the region of 2.2 to 3kW. Even that will put significant
demands on your supply and still be well short of power compared to the original spindle motor. I recall that you thought that operation
from a single phase supply would be a favourable selling point, and I imagine it is....but are you planning on selling it?
You will have noted that the higher the input voltage to the drive the faster the servo can run before the torque diminishes. That would lean you to
a three phase input servo drive, but that really is contrary to the idea of running it from a single phase supply.
I understand that you are going to buy a couple of 750W servos and drives for the axis drives. I commend that idea to you, it will give your lathe a new
lease of life. May I suggest that at least for the time being that you retain the existing three phase spindle motor while you get your axis drives and
controller on line. I suspect that the experience you gain with programming and handling the smaller servos will give you good insight to the potential
performance of a larger servo for a spindle and also maybe an appreciation of it problems also.
If you are dead set on having a servo as a spindle motor, and as you know I have done just exactly that for my mill and delighted with it, then you will want
the most capable motor you can afford and/or your electrical installation handle. That would tend to favour 400V drives, the servo being run with such a drive
goes that much faster and retains its torque that much longer. I would think that the exemplary torque characteristics of a servo would mean that a 4kW servo
would hold its own handily with a 5kW induction motor, if not absolute power, but the handling characteristics would be favourable. Below about 4kW
and I suspect that you would start to notice the lack of power.
A 400V servo and drive capable of 4kW is not going to be cheap, even at the discount your wife can secure. Also a large servo like that is going to place
real demands on your supply and you would have to allow some budget to improve that situation as best you can, I'd think line reactors as a minimum.
Craig
what are you trying to achieve? If I understand correctly you have a working three phase asynchronous spindle motor of 5kW.
Is that correct?
What are you hoping to achieve by replacing it? You mentioned the desirability of having it operate from a single phase supply.
Hood and I chimed in and we agree that the potential for a single phase servo is in the region of 2.2 to 3kW. Even that will put significant
demands on your supply and still be well short of power compared to the original spindle motor. I recall that you thought that operation
from a single phase supply would be a favourable selling point, and I imagine it is....but are you planning on selling it?
You will have noted that the higher the input voltage to the drive the faster the servo can run before the torque diminishes. That would lean you to
a three phase input servo drive, but that really is contrary to the idea of running it from a single phase supply.
I understand that you are going to buy a couple of 750W servos and drives for the axis drives. I commend that idea to you, it will give your lathe a new
lease of life. May I suggest that at least for the time being that you retain the existing three phase spindle motor while you get your axis drives and
controller on line. I suspect that the experience you gain with programming and handling the smaller servos will give you good insight to the potential
performance of a larger servo for a spindle and also maybe an appreciation of it problems also.
If you are dead set on having a servo as a spindle motor, and as you know I have done just exactly that for my mill and delighted with it, then you will want
the most capable motor you can afford and/or your electrical installation handle. That would tend to favour 400V drives, the servo being run with such a drive
goes that much faster and retains its torque that much longer. I would think that the exemplary torque characteristics of a servo would mean that a 4kW servo
would hold its own handily with a 5kW induction motor, if not absolute power, but the handling characteristics would be favourable. Below about 4kW
and I suspect that you would start to notice the lack of power.
A 400V servo and drive capable of 4kW is not going to be cheap, even at the discount your wife can secure. Also a large servo like that is going to place
real demands on your supply and you would have to allow some budget to improve that situation as best you can, I'd think line reactors as a minimum.
Craig