Union Graduate Power Consumption

[nigelwest1965]

Hi Folks

I've just bought myself a Union Graduate lathe which is on 3 Phase power and I'm trying to find details on power consumption so I can get hold of the correct inverter for it.

I have a serial number that is either 666985 or 866985.

Can't read very well the information on the casing (I only have a photo) but seems to state that it is 380/440V 50Hz 1.0/1.7 Amps, my electrician tells me that this is very low so I'm just looking for some opinions on here. Also, if people on here are successfully using inverters, what are you using.

Thanks for any help,
Nigel.

 

[CHJ]

Sounds like you have a motor somewhere in the region of 1HP, not unreasonable, My Poolwood 3PH has nominal I HP motor.

See these charts for some typical figures

 

[TFrench]

Don't get the bosch rexroth inverter, its a pig to set up!

 

[flh801978]

As standard they only came with a 3/4 hp motor which is fine for spindle turning
Most users upgrade to a larger motor
I have 2 graduates one long bed with the original 3/4 and a short bed with a 1.5 hp which can still stall on large bowls

Your current rating is correct for a 3/4 hp on 415v

Ian

 

[minilathe22]

I am using the Yaskawa j1000 model cimr-jcba0006baa which has a limit of 1.1kW. My motor states 2.2amps at 220V and 1.25amps at 380/440V, and is a 3/4HP unit. I believe you wire the motor connections slightly differently if using the higher voltage.

General advice I have read is to have the power rating of the inverter slightly higher than the motor is best. Getting the settings in the inverter right takes some time, they are designed to power motors in a variety of different situations. I found that on the slowest belt speed, I have reasonable torque as low as 100rpm. I can run the spindle as low as 40RPM, but you can stop the spindle with your hand, the torque is no good for turning. You can also overspeed the motor to give you higher spindle turning speeds, with (presumably) a higher risk of motor failure. I wired it myself, took most of a day to setup.

 

[graduate_owner]

My graduate has a 1 hp motor but I intend to change to 3 phase, with a larger motor if I can get one at a sensible price. I have a 3 phase inverter already for other machines, it is a 3 hp Invertec from ebay, not a Far East import (which I have read bad reviews for). I went for 3 hp ' in case ' but so far the largest motor is 1 hp, still, plenty of spare capacity. I don't seem to have any issues with setting up for different motors, I just connect up and go. Not sure about low speed torque parameters yet.
A couple of points though -
1. At low speed the cooling fan also runs slowly so overheating may be a risk. I was thinking to fit a separate small motor and fan, single phase, just for cooling.
2. My inverter is not IP 65 rated, it has a much lower rating, meaning that dust and damp can cause problems. I suspect my previous inverter died because of that. The instructions on mine say to fit in a suitable IP rated enclosure, so I fitted it into a metal cabinet with loads of space all around, especially above, plus I intend to wire in a thermal cut out set at 50 degrees. This may seem like overkill but I don't want to have to buy another inverter.

Hope this helps.

K

 

[donie]

3/4 hp was standard measure, same for most big lathes of that era.

If you want the cheapest way to get it to run on single phase a Chinese inverter off eBay is your best bet. You wont get a 550w or 3/4 hp one but 750w or 1hp should work fine. I have one of these on a table saw for a few months now, works well no complaints. shop around though. see ebay link here
http://www.ebay.ie/itm/ECO-Single-P...806636?hash=item1c8a62abec:g:CZUAAOSwHLNZWf0P

Drives direct are another UK based company, they do a motor and inverter package too see here
http://stores.ebay.co.uk/drivesdirectinvertersltd

If you have a 380v or 415v motor it is wired in star configuration and it will need to be wired in delta to let it run on 220v. Most motors have a terminal box where you can easily change, I think graduate lathes might have just a star wound motor and a motor rewinds place could wire it in delta for you.

Hope that helps!

 

[Ttrees]

I just found out recently that a fixed star wound motor can actually be used with a VFD,
but I'm not even sure you get even half the torque.
Look for a dual voltage motor is my suggestion.
I aint sure what pole motor (RPM) it should be though ?
Tom

 

[minilathe22]

Union graduate is a 4 pole motor (1400rpm approx). I dont think the vfd is bothered by the number of poles.