Emcomat 20E Retrofit??

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08 Apr 2015 07:47 #57620 by Mtndrew77
Does anyone have any recommendations for suppliers of spindle motors and VFDs?. I have a Emcomat 20E that I am finally getting around to retrofit and it has
a 380V 7.5hp 3phase AC motor spindle motor. I'm thinking trying to intergrate 25 year old drive components to linuxcnc may be more trouble than it is worth, and at least
for now beyond my novice abilities. Does anyone have any recommendation on a 3-5 hp motor drive combo that would give me a more straight forward install? Any advice is appreciated, Thanks

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08 Apr 2015 18:40 #57628 by andypugh
Replied by andypugh on topic Emcomat 20E Retrofit??

Does anyone have any recommendations for suppliers of spindle motors and VFDs?. I have a Emcomat 20E that I am finally getting around to retrofit and it has
a 380V 7.5hp 3phase AC motor spindle motor. I'm thinking trying to intergrate 25 year old drive components to linuxcnc may be more trouble than it is worth


I think that changing the motor might be more trouble than it is worth, actually.
Does the existing motor drive offer variable speed?

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09 Apr 2015 00:13 #57631 by Mtndrew77
Replied by Mtndrew77 on topic Emcomat 20E Retrofit??
Yes it was variable speed and I'm sure someone with more electronics experience would be able to tie it in, but I have other reasons I want to swap.
Mainly I don't want to have to buy a phase converter then route it through the transformer and back into the lathe and hopefully figure out how to tie it in. Either way I'm going to have to spend
money. Either buy a phase converter or new motor and drive. So I guess my logic is to go the path of least resistance or at least the one I think is the least resistance.

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09 Apr 2015 00:49 #57632 by andypugh
Replied by andypugh on topic Emcomat 20E Retrofit??

So I guess my logic is to go the path of least resistance or at least the one I think is the least resistance.


It sounds like you might need less resistance :-)

Is the issue that you don't have a 380V supply? It might be worth seeing if the motor can be re-connected in delta mode to run as a 240V motor. Then (if you have 240V) you can run it with only a standard VFD.

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09 Apr 2015 02:55 #57635 by Mtndrew77
Replied by Mtndrew77 on topic Emcomat 20E Retrofit??
No I have the transformer I need to take 220 3phase to 380, but I would still need the phase converter. I was under the impression
(maybe mistaken) that for motors under 5hp you could buy a VFD that would take single phase to three phase. That's why I was thinking
just get a smaller motor and drive and move on. So I take it you think I should try and tie in to the old drive? I'm not sure where to even start
on that one. Any Suggestions?

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09 Apr 2015 03:36 #57636 by andypugh
Replied by andypugh on topic Emcomat 20E Retrofit??

No I have the transformer I need to take 220 3phase to 380, but I would still need the phase converter.


You don't necessarily need a phase converter as such, you could use a single-phase input VFD running at 380V and keep the same motor.

I was under the impression
(maybe mistaken) that for motors under 5hp you could buy a VFD that would take single phase to three phase.


Well, the first thing that any VFD does is convert the incoming power (3 phase or single phase) to DC, then it creates three phases from that. However VFDs that step-up the voltage are very rare.

Most three-phase input VFDs could run on single-phase power, except that many detect the missing phases and error-out.

So, you can _probably_ run the existing motor from a single-phase fed 380V VFD, or potentially re-wire the motor for Delta (220V) operation and run it from a 220V single-phase input VFD.

Your existing drive probably won't run on single-phase 380V or single-phase 220V, but there is nothing to be lost by trying it to see.

7.5HP single-phase input 230V inverters do exist, but are nor cheap:
www.inverterdrive.com/group/AC-Inverter-...2K2-5kW-230V-Single/
And will only work with the existing motor if it can be re-wired (most motors can, you need to check the rating plate).

Whether changing the motor makes sense depends on how standard the frame is (and potentially what you can sell the existing motor and drive for).

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09 Apr 2015 04:55 #57637 by Mtndrew77
Replied by Mtndrew77 on topic Emcomat 20E Retrofit??
:woohoo: Thanks! that might just do it. I have to double check the motor

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09 Apr 2015 19:04 #57646 by BigJohnT
Replied by BigJohnT on topic Emcomat 20E Retrofit??

No I have the transformer I need to take 220 3phase to 380, but I would still need the phase converter. I was under the impression
(maybe mistaken) that for motors under 5hp you could buy a VFD that would take single phase to three phase. That's why I was thinking
just get a smaller motor and drive and move on. So I take it you think I should try and tie in to the old drive? I'm not sure where to even start
on that one. Any Suggestions?


It is surprisingly easy to build a self starting rotary phase converter.

gnipsel.com/shop/rpc/rpc.xhtml

JT

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12 Apr 2015 08:49 #57705 by Mtndrew77
Replied by Mtndrew77 on topic Emcomat 20E Retrofit??
Okay, sounds like I'm being shamed into at least trying. For some reason I was thinking that the old CPU and the VFD were more interconnected than just a control signal. That doesn't appear to be the case.
So my next newbie question is What does N_sull mean? Attached is a print of the main drive control
Attachments:

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14 Apr 2015 16:09 - 14 Apr 2015 16:10 #57785 by Einar
Replied by Einar on topic Emcomat 20E Retrofit??
It is actually N_soll and stands for sollwert. That is Your setpoint input controlling the motor speed.

In this day and age I consider a rotary converter a dinosaur! Huge losses compared to transformers, and noisy.

If you need to step up the voltage use a transformer. Or use 3 transformers for 3-phase if you can get them cheaper than one 3-phase transformer.
On my Boxford there are 3 transformers built into the lathe from the factory, which is convenient.

You already have the motor and VFD (which Emco for some strange reason Calls a CPU-Board!?)
It has another setpoint input from what they Call a spindle override switch (1), but it really is a potentiometer.
My Guess is it give you the possibility to run the motor faster or slower than the programmed speed.
Last edit: 14 Apr 2015 16:10 by Einar.

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