Emcoturn 120 lathe retrofit

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01 Jun 2016 13:49 - 01 Jun 2016 13:54 #75302 by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
for you electricals out there, here is a question. It looks like the original lathe required 400V 30A, so I assume I should be around 55A at 220V. here are my loads, please also review these and see if I am on the right track.

1. 5hp motor and VFD: 19.6A@220max
2. 24vdc PSU: <1A@120
3. 5vdc PSU: <1A@120
4. Dell FX170: <1A@120
5. x-axis drive: 2.8A/ph 14A@70vdc 9A@120
6. z-axis drive: 2.8A/ph 14A@70vdc 9A@120

total required ~ 31A@220

so do I size the breaker and cord for 50A or do can I use 30A?

thanx
Last edit: 01 Jun 2016 13:54 by LutzTD.

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01 Jun 2016 14:38 #75303 by andypugh
You almost certainly can use lower-rated breakers. You might even want to. If you are running full power on the spindle and both axes both at the same time it is likely that something has gone badly wrong.

There is a concept in rating for wiring and breakers called "diversity". You don't assume that every part of the system is running full power all of the time.

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01 Jun 2016 17:08 - 01 Jun 2016 17:12 #75305 by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
here are my thoughts on the power wiring. what recommendations for fuses at these locations? Or are the locations wrong? I was planning to use the 25A ceramic holder/fuses in position 1 and the 6a/leg breaker in the "breaker" location but now I think these may be too large a value.


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Last edit: 01 Jun 2016 17:12 by LutzTD.

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01 Jun 2016 18:50 #75306 by andypugh
I don't have any actual fuses in my system, I use MCBs throughout. They are so cheap that it seems pointless not to.

I have a single 20A for the motors and two 3A ones for the switched and unswitched low-voltage supplies.

So, there is a 3-pole isolator switch (with only 2 poles in use) feeding a single 3A breaker and the main contactor. That breaker feeds a 24V supply for GPIO (and the main contactor) and a 12V supply for the PC. The main contactor then powers the 20A breaker for servo and spindle power and a second 3A breaker for the spindle gearbox clutches and brake.

The 20A breaker is C-rated for motor use. The 3A ones are not, but soon will be, as the 3A B-rated type tend to trip on the inrush current of the PSUs.

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01 Jun 2016 20:36 - 01 Jun 2016 20:37 #75308 by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
so I would want to ?

replace fuse 1 with 2 pole or 3 pole 20amp/pole MCP, how do I know if it is c rated?
replace "breaker" with 2 pole 3A/pole MCB
replace "5" with 2pole 10A/pole MCB
get rid of 2,3,4 and 6.
Last edit: 01 Jun 2016 20:37 by LutzTD.

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01 Jun 2016 23:53 #75312 by andypugh

replace fuse 1 with 2 pole or 3 pole 20amp/pole MCP, how do I know if it is c rated?.


It says on the front. (well, it does here, things might be different where you are).

www.tlc-direct.co.uk/Main_Index/Consumer...ssories_1/index.html

There are types A and D too, but you rarely see them.
A bit of extra detail: www.tlc-direct.co.uk/Technical/Distribution/Mcb.htm
The following user(s) said Thank You: LutzTD

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02 Jun 2016 02:37 #75318 by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
thanx, I also did a little research. I like to stick with names I know when it doesnt cost too much more. I ended up getting 3 double pole breakers made by Allen Bradley, a 1489-A2C200, 1489-A2C100 and a 1489-A2C030, which are 20A, 10A and 3A respectively. The third digit "C" in the second part of the number designates the C rating, ( I downloaded the catalog to find this out) These are from surplus dealers on ebay. They were about $15 each for NOS units, so not too much different.

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02 Jun 2016 16:44 #75341 by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
I like to work in graphics to wrap my head around it, so here is my power layout


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02 Jun 2016 16:52 #75342 by andypugh
You can probably take the 5V supply from the PC PSU, it might even be advantageous from the point of view of ground commonality between 7i76 logic and the PC.

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02 Jun 2016 17:06 - 02 Jun 2016 17:52 #75344 by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
I was wondering about that. The FX170 has a 12VDC wall wort PSU. The 5VDC for the toolerator3000 comes from the USB on the FX170. Could I use the USB port as a 5V source for the Mesa as well? (with a USB BOB) It connects with a Ethernet already but I don't think the Ethernet supplies 5V

EDIT: something like this?





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Last edit: 02 Jun 2016 17:52 by LutzTD.

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