[aarongough]

Hey all!
I'm looking for a decent AC servo to use as the spindle motor in my lathe build... The only problem is I really only have access to 110v power.

The AC servo packages from AutomationTechnologiesInc look pretty much perfect in that the drives offer speed and position control modes, and they're in the power/price range that I want, however they're all 220v input.

I've had a look around and I haven't found any AC servo drives that take 110v, so I'm kind of stuck.

Anyone have anything they can point me to? I'm looking for something around 1KW and it must have a dual (speed/position) interface.

Thanks!
-Aaron

[mactec54]

aarongough

Dmm-Tec
Have what you are looking for, they do 48V 110v & 220v

DMM Technology Corp.

[aarongough]

Looks perfect! Thanks very much Mactec!

[aarongough]

And they're in Canada too! Brilliant!

[wizard]

Step up transformers work if you can supply the current. It is a good solution for a long term projects where you might have 220 volts at a later time.

[aarongough]

Step up transformers work if you can supply the current. It is a good solution for a long term projects where you might have 220 volts at a later time.

Thanks, good to know! I hadn't given a transformer much thought as I had assumed it wouldn't be up to the job...

The rest of the build is all 110v, so it's nice and neat if the spindle driver works out to be 110v as well.

I talked to DMM about their drives this afternoon and they seem ok. A little difficult to deal with because of a language barrier, but their prices are good and the service was prompt. I'll probably get the drive from them in a week or so.

[asuratman]

How about power requirement? is that enough power, their servo max power is 2 kw if not wrong.

[aarongough]

How about power requirement? is that enough power, their servo max power is 2 kw if not wrong.

Yeah, their servos max out at only 2Kw. I'm actually getting a smaller one though, only 0.75Kw.

The lathe I'm building is quite small. It will be used for production work but it doesn't have to be super fast, so in this case I'm happy to trade off some power to keep the cost low.

I'll also only be swinging stock up to about 1" diameter, and there'll be no live-tooling cuts taken without the spindle brake active, so I don't need the extra power to counteract cutting forces.

Feel free to point out if you think any of my reasoning is flawed though! I appreciate any input!

[wizard]

Thanks, good to know! I hadn't given a transformer much thought as I had assumed it wouldn't be up to the job...

In the cases where I've worked on machinery using such, much of the power the machine was using went to 120 VAC loads. They where also feed with a large 40'amp supply. The problem you have, of may have is getting the solution to work on a wall outlet provided current. In the USA common wall outlets are on either 15 or 20 amp circuits. That could become a problem depending upon what the rest of the machine controls require.

The rest of the build is all 110v, so it's nice and neat if the spindle driver works out to be 110v as well.

It is only nice if you can plug it into a wall outlet and run the machine reliably. If you find that that is a problem you will be far better off wiring up 220 volt feeders for the machine assuming a single phase only plant location.

Obviously there are a lot of ifs and and buts here. You need to know the total power draw at the expected machining conditions. Of course you can always adjust machining conditions to make the machine work within the capacity of the 110 vac circuit itis plugged into.

I talked to DMM about their drives this afternoon and they seem ok. A little difficult to deal with because of a language barrier, but their prices are good and the service was prompt. I'll probably get the drive from them in a week or so.

Consider a local supplier that doesn't have the language problem. Seriously there are many suppliers out there, why suffer through the grief of misunderstandings and the like.

By the way I seem to remember somebody making a AC drive that took 120 in to drive 220 vac 3 phase motors. That might be a solution for you but I can't remember the vendor at the moment.

[wizard]

Here is a solution similar to the one I was thinking about in the previous response: 500 Error)

It is an AC drive that takes 120 in to drive 220 vac three phase motors.

Yeah, their servos max out at only 2Kw. I'm actually getting a smaller one though, only 0.75Kw.

You say servo but do you really need a servo? I don't know but below you indicate holding torgue isn't an issue.

The lathe I'm building is quite small. It will be used for production work but it doesn't have to be super fast, so in this case I'm happy to trade off some power to keep the cost low.

All engineering is a series of trade offs. Low cost would imply minimizing the use of servos if possible.

I'll also only be swinging stock up to about 1" diameter, and there'll be no live-tooling cuts taken without the spindle brake active, so I don't need the extra power to counteract cutting forces.

Do those cuts require spindle positioning? The requirement to index the spindle will make the machine a bit more than low cost.

Feel free to point out if you think any of my reasoning is flawed though! I appreciate any input!

I don't see flaws so much as not having a clear idea as to what you are up to. You seem to indicate a need to index the spindle yet you are looking for a low cost solution. That might require that you do something mechanically to lock the spindles or orient the live tooling.

[mactec54]

wizard

The AC servo Drive/motor,That aarongough is looking at, Can take 110V/220VAC single Phase or 220VAC 3 phase

[aarongough]

Here is a solution similar to the one I was thinking about in the previous response: 500 Error)

It is an AC drive that takes 120 in to drive 220 vac three phase motors.


You say servo but do you really need a servo? I don't know but below you indicate holding torgue isn't an issue.

All engineering is a series of trade offs. Low cost would imply minimizing the use of servos if possible.

Do those cuts require spindle positioning? The requirement to index the spindle will make the machine a bit more than low cost.

I don't see flaws so much as not having a clear idea as to what you are up to. You seem to indicate a need to index the spindle yet you are looking for a low cost solution. That might require that you do something mechanically to lock the spindles or orient the live tooling.

Wizard: You're spot on with everything you've said, and I appreciate the input!

The plan is to have spindle indexing, but no 'true' C-axis... I'm going to setup a spindle brake (of a type yet to be decided) and any cuts with live tools will be done with the spindle brake engaged.

I have a somewhat limiting set of requirements: I can only get 110v power, though I can get a dedicated 20A circuit for the machine. I also have *extremely* limited space (my metal shop is about 75 sq ft at the moment).

The only servo on the machine will be on the spindle, the other axes will be controlled by a G540. So will 20A power be enough? Will the peak servo draw greatly exceed the quoted 750W figure? I had guessed at a worst case of maybe double? 1500W?

The general idea is that I'm building a small gang lathe designed to do work on 1" or smaller bar stock. It's going to be used for 'light production' which will likely mean about 10-16 hours a week of runtime. It's not vitally important that it churns our parts fast, as any time it's working is time it's giving me to work on packaging and other stuff that requires manual work.

The lathe will mainly be producing small parts out of 6061-T6 for pens and flashlights.

Live tooling will only be used to mill flats and maybe cross-holes. If there's a better/easier/cheaper way to index the spindle for the live-tool operations then I'm definitely open to it! I could make an encoder disk I guess ( I have done it before when making a spindle tach) but I had assumed that most standard VFDs or PWM drives wouldn't give me the finesse needed to sneak up on the edge of an encoder disk slot...

The vendor with the language problem, surprisingly, is local... I'll continue to have a look for other vendors but I clearly haven't gotten the knack of sourcing this stuff yet, it's a skill like anything else!

My budget for the lathe is about $2500, not including tooling. It's going to be a bit tight but I can sink in some extra out of pocket if things run over.

Thanks! I appreciate all the input!

[mactec54]

aarongough
The vendor with the language problem

Hui's english language can be hard to understand, But his son speaks perfect english, he is overseas right now otherwise you would of been speaking to him, he normaly handles all sales & Tec support, If you need to know anything & can also help you with any Tec support as well

Having the Encoder on the servo is all you will need for your indexing

If you are putting in a 20amp circuit, then make it 25amp, 20amp will be enough for your system but 25amp if you can would be better

[Al_The_Man]

The plan is to have spindle indexing, but no 'true' C-axis... I'm going to setup a spindle brake (of a type yet to be decided) and any cuts with live tools will be done with the spindle brake engaged.

Electroid make a nice line of electro-magnetic brakes.
You can also get motors with brakes on them.
The brake and encoder can only be on the motor if the coupling is a tight single type, timing belt etc, not gear head or other, if this is the case then you need the encoder and brake on the final spindle shaft for C axis control.
Al.

[TiagoSantos]

Like Mactec54 said, Hui (although very knowledgeable) can be hard to understand. His son speaks perfect English though, and should be back in about a week from what I hear!

Their office is about 15 minutes away from me and I've met them a couple of times, I have no reservations in dealing with them..

[TiagoSantos]

As far as circuits, etc - 220v really isn't that big a deal.. If you're within range of the panel, consider a long power cord to a receptacle installed near the panel. That's how I'm wiring my mill - 30A double pole breaker (20 bucks..) at the panel with a receptacle installed about a foot from the panel box. Then a 25ft 8 gauge power cord (8 gauge is a bit overkill, but it's what I had - otherwise, large gauge 4 conductor cable gets expensive quick..) to the controller. If you get 4 conductor cable, you can easily have 220v and 110v inside the controller Just something to consider!

[aarongough]

Like Mactec54 said, Hui (although very knowledgeable) can be hard to understand. His son speaks perfect English though, and should be back in about a week from what I hear!

Their office is about 15 minutes away from me and I've met them a couple of times, I have no reservations in dealing with them..

Thanks to Mactec and Tiago for reassuring me on this front.

They were pleasant to deal with via email, but the phone conversations were a little hard. Given that you guys have vouched for them I shall go ahead and order the servo from them!

[aarongough]

As far as circuits, etc - 220v really isn't that big a deal.. If you're within range of the panel, consider a long power cord to a receptacle installed near the panel. That's how I'm wiring my mill - 30A double pole breaker (20 bucks..) at the panel with a receptacle installed about a foot from the panel box. Then a 25ft 8 gauge power cord (8 gauge is a bit overkill, but it's what I had - otherwise, large gauge 4 conductor cable gets expensive quick..) to the controller. If you get 4 conductor cable, you can easily have 220v and 110v inside the controller Just something to consider!

If I was in a shop that I owned then yeah, I wouldn't be too worried about it. I'm in a shared space though unfortunately so I'm a little limited with regards to the changes I can make.

Thanks for the input! It's all appreciated!

[aarongough]

Electroid make a nice line of electro-magnetic brakes.
You can also get motors with brakes on them.
The brake and encoder can only be on the motor if the coupling is a tight single type, timing belt etc, not gear head or other, if this is the case then you need the encoder and brake on the final spindle shaft for C axis control.
Al.

Thanks Al!
I will look that stuff up!

I was thinking a brake directly on the spindle as I haven't worked out the control method yet, but it might make more sense to build some sort of jack-shaft that would attach to the servo via a zero-backlash coupler, then run the timing-belt drive pulley and brake on the jack-shaft. Does that sound reasonable? That way I wouldn't have to mess around fitting the brake directly to the spindle.

Do I need to worry about stretch in the timing belt allowing the spindle to chatter around it's axis when machining with a live tool? I'm fine with taking only light cuts.

I'm getting excited about this build as it seems like things are starting to come together!

[Al_The_Man]

You won't need to worry about belt stretch in that application with an appropriately sized belt.
Al.