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lolosPL
11-03-2018, 07:51 PM
Hello everyone
I am converting harrison 280 lathe to cnc. One of the drivers is broken so I am going to upgrade both of them to MA860H (110VDC max), ...any opinion about them? There is so many drivers on ebay... is very difficult to find the difference between them.
I don't know what current I suppose to set for a stepper motors (labels on them are wiped off). Does anyone knows what current are they? Old drives PKS digiplan cd20 and cd40.

Thanks

m_c
11-03-2018, 08:20 PM
I'd guess only a couple amps. Generally lathes designed for school/colleges are pretty detuned to try and minimise damage during the inevitable crashes.

Manuals should be available for the drives (just search for parker CD20/CD40), so you should be able to work out what current they were set at, if there's not a chart on the drives themselves.
Failing that, I'd start about 2 amps, and monitor motor temperature. After 20-30minutes, at peak current the hottest they should be is just verging on not being able to hold your hands on them. If they heat up more than that far sooner, drop the current. If they're still cool to touch, you can increase current if you think you need more performance out them.
If they're old round body steppers, upgrading them to newer square motors will give better performance, but gains are probably not that great on something relatively slow like a lathe. Upgrading the drives is where you'll get the biggest improvement anyway.

JAZZCNC
11-03-2018, 08:52 PM
You need to be careful with these drives because there are lots of copies of the original leadshine MA860H. Many still use the same MA860H reference but are not actually Leadshine drives.
Also they are Analog drives which is Old technology. You'd be much better with Digital drives the performance and smoothness is so much better. They are also far more tolerant of incorrect settings like current and won't heat the motors as much.

Something like these will give much better performance for not lot of money.
https://www.omc-stepperonline.com/stepper-motor-driver/digital-stepper-driver-24-72a-18-80vac-or-36-110vdc-for-nema-34-motor-dm860t.html?mfp=16o-ship-from%5Bunited-kingdom%5D