[Stevie]

Hi guys
I was running the 310oz/in JapanServo KP86SM2-002 temp/y on my Z axis with my Zeta4 drive; it was just sitting on the bench; and the AL drive which was mounted below the bench top and originally ran the 65oz/in (57-51) stepper for Z
I thought well as the longer stepper (2stage 57-83) is still a week or 2 away I'd simply up the amps from the AL drive to 3.00 and switch drives (the Zeta4 was set to 4.00)
I figured a drop in holding power was all would happen

Low and behold; the motor hit 46dgrC in 10 mins; it never got above 28dgr after running most of the day on the Zeta4
The steps are set the same; the wave form is the same too; now why would less power do this; I'm scratching my head

[ESjaavik]

My drives have a feature where they will drop the current if there are no step commands coming. This will significantly lower the heating and still keep the holding torque high enough to keep it in place. Usually there is no or little force trying to move the axis when not moving. Maybe your Zeta4 have the same?

And 46C is not hot. Above 100C is hot. There's a reason a lot of machines have a warning not to touch the motors. :-)

[Stevie]

Yeah I have the feature enabled; cuts the current to 1/2
Both drives have it; like I said i set both to the exact same; other than the 3amp to 4 amps as the AL can only give 3 amps
The Zeta runs the motor great but with a slight resonace at about 3 rpm; I could tune it out but as it was just a temp/y thing I didn't bother
The AL really drives it nice; no resonaces at all; but this heating; if it hit 46c in 10 mins; what would it do in 1 hour; I really don't want to find out
The Zeta must have some kind of circitry that is better with the Japan servo than the AL; the AL is older tech
My last big drive arrived tonight (S6) now I have 2 AL's -2 S6's -1 Zeta4 -1 AXL -SuperVexta UDK5114N-E (5 phase)
THe AXL will be made into a toolchanger I think as it's fully programmable and can accept microswitch inputs to trigger other automatic operations (only gave 29.95 for it plus shipping)
The Vexta will become my spindle drive for stepping to degrees when the lathe is used as a 4 axis (spindle becomes C)
I got the Vexta for 26bucks and it's brand new; but no manual; I really need a manual for this

[balsaman]

It will probably be 46 degrees after 1 hour. These motors come up to temperature and stabalize at a point where they can disapate their losses (heat) indefinately.

Eric

[Stevie]

Hi Eric

I did mount the stepper on that big 1/2" x 12" alumi as a heat sink; I just don't like the thought of fried stepper for supper; and as these where bought for the mill project I'd be p***** off

I do have a couple of 57-83's coming plus a 5 phase (Vexta) and a bipolar 250oz with encoder
I also grabbed a servo with Copley drive; but as for just how powerfull the servo is; I have to wait for it to arrive (another week)
I also got what I thought was a real deal; 13,000 rpm 1/4 HP 50Vac/24Vdc for 3 bucks chk out item #3813415642 eBay
Here's the Copley/QMC item#3813064287

Let me know if you have any idea on the QMC size

[Stevie]

I've got to the bottom of this problem
The AL drive has a lower limit of 20mH inductance
The Zeta and S6 drives have a much lower tolorance 2mH with a recommendation of 5mH min
I figure thats the heating of the stepper motor explained

I've just got my 240oz/in Eastern stepper (23 size) Z axis
I'll be using it from now on; the smaller single stack Compumotor (A57-51) stepper is also out of there for a new Compumotor A57-83 for the X axis

The Eastern will use the Zeta4 for a while; the spare AL drive can wait for the mill conversion and then it will be teamed with another A57-83 I'm awaiting and will be the mill version of this machine Z axis drive