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Author Topic: CS Labs CSMIO/P-A  (Read 15173 times)

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Re: CS Labs CSMIO/P-A
« Reply #130 on: August 03, 2018, 02:38:44 PM »
Hi Craig

I was going to use a smaller sprocket on the motor. They are belt driven at the moment.

The two motors I was referring to will fit no problem. Just need to get a plate made. The motor I was going to get was a 1kw BCH2MM102∙C∙6C. The Circle diameter of the mounting holes is 145mm. Which will not be a pretty fit on the x-axis.
I think we have established that motors BCH2LF073∙C∙5C or the BCH2LF073∙C∙5C are close to spec but Hood suggested slightly underpowered. Hence why I was thinking of gearing down as I don't need 3000 rpm on rapids.  

I can send you links to the motors if you wish.

Cheers
Mick

Re: CS Labs CSMIO/P-A
« Reply #132 on: August 03, 2018, 03:00:05 PM »
Hi,
when I read the spec of the BCH2.F I saw a continuous torque of 2.39Nm which is slightly more than the SEM's you are replacing.
That's plenty.....you will never even get close to absorbing the power that servo can produce....underpowered! :o

Remember also that power is torque times speed. Even without changing the gearing the BCH2.F will have more power right throughout its
rev range up to 3000 rpm, thereafter the SEM nudges ahead. Will you ever get close to 3000 rpm? 1:1 on 5mm pitch screws is 15m/min,
so not even close.

We have a customer who has an oldish twin column Okuma CNC, its freaking GINORMUS, and its Y axis motor is 1hp. It lunks around the
main spindle which is 50hp and weighs 1/2 a ton or more.

A 1hp axis motor will drive your lathe within an inch of its life!. You would still end up with a satisfying build by gearing down 200W servos,
you might start to notice the reduction in rapid traverse but you wouldn't see much difference otherwise.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #133 on: August 03, 2018, 04:26:57 PM »
Hi Craig

Thanks for the links but makes no sense to me to buy used motors when I can get branded stuff at such a great price.

Think I will definitely go for the smaller motors and yes I don't need 15m/min, half that is plenty. What are your thoughts on the two different models? High and low inertia. I have tried reading up on it but a little bit over my head. 

Cheers
Mick

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Re: CS Labs CSMIO/P-A
« Reply #134 on: August 03, 2018, 04:35:47 PM »
Just read the last few posts. My assumption on the SEMs was they were 900w at 2-2500 rpm but the pic shows it is 4000rpm.
The 750W Schneiders on RS said 5000rpm but I now see that is Max RPM and rated is 3000 and so 750w at rated so yes the Schneiders are both more powerful and have more torque than the SEM in the range you will be using them. The SEM would be about 670w at 3000rpm.

I will see if I can dig up a Torque curve for the SEMs but usually the torque starts to drop off on these motors around about 1-1500rpm where AC servos it tends to stay constant right up to rated RPM.
.

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Re: CS Labs CSMIO/P-A
« Reply #135 on: August 03, 2018, 04:39:48 PM »
Ok here are the curves for both SEM and Schneider.
The SEM starts to drop off at 1000rpm and at 3000rpm it is probably around 1.5Nm where the Schneider doesn't tail off until the rated rpm of 3000.

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Re: CS Labs CSMIO/P-A
« Reply #136 on: August 03, 2018, 04:41:10 PM »
Ah, SEM one didn't load, hopefully it is attached now.

Re: CS Labs CSMIO/P-A
« Reply #138 on: August 03, 2018, 05:14:18 PM »
Hood

Thanks for the detailed explanation and time taken. I have got all this info but hard to syphon through with lack of experience. What would be a better choice the high or low inertia?

Cheers
Mick

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Re: CS Labs CSMIO/P-A
« Reply #139 on: August 03, 2018, 05:31:12 PM »
Not sure what it is going on without reading back, think a lathe but unsure the size. As mentioned above I had the MPL motors on a Bridgeport and they are now on a slightly larger mill and they do fine, they are Low inertia (the L in MPL)
It is obviously not a massive lathe going by the original motors so likely the low inertia will be fine. For a definitive answer you would really need to work out the inertia ratio, there are online calculators to do that if you feel the need.