Union Graduate/Hitatchi Inverter question

[Bills Elm]

I have been offered an Hitachi SJ100 inverter for little money, like this one here below...

http://www.automationdirect.com/static/ ... /sj100.pdf

The question I have is.. This is for a 2 horse motor but can it be programmed to run the 3/4 horse motor in my Graduate or is it not suitable?

My motor is a dual voltage that has been changed to star from delta so that's not a problem and it's a four pole motor which I know can be setup in the software of this inverter but I'm just not sure if and how the amps/plate current can be changed to suit my 3/4 horse motor.

Bill

 

[Paul Hannaby]

From the manual, you need to look at group H for motor capacity setting and group B for thermal overload characteristics so the overload current is matched to the motor capacity.

 

[Bills Elm]

From the manual, you need to look at group H for motor capacity setting and group B for thermal overload characteristics so the overload current is matched to the motor capacity.

Thanks Paul

So you think it can be done then? I know very little about electrics and if I buy it I will have to get an electrician to wire it for me, so I really just need to know if it's ok and that it will work with my motor.


Bill

 

[graduate_owner]

Hi Bills Elm,
regarding your inverter issue:-
I have a 2 HP Eurotherm 3-phase inverter (not a plug and play type) which I use on my Myford ML8 and Union Graduate - both 3/4 HP. I originally bought it for my milling machine which has a small 3-phase suds pump motor as well as the main 1 HP motor. I use a 5-pin 3-phase socket to connect to the inverter, and matching plugs on lathes and milling machine, and just plug in to the inverter as required. So far I haven't had any problems - they all seem to work fine, even with the two different sized motors on the milling machine running at the same time.

I said they 'work fine', but the motors have fairly low torque at low speeds ( already in delta connection) although still quite useable. In the instructions there doesn't seem to be a parameter to set for low speed torque, so I just go ahead and use it at default settings. The only change I've made to mine is to disconnect the wimpish cooling fan and replace it with a separately powered (ex computer psu) fan which gives much better cooling.

I have read that you need a plug and play type (quite a bit more expensive) to be able to use it as I am doing, but as I said it seems to work. I've been running things this way for over 2 years - so far so good.

So if your Hitachi is going cheap, then if it was me I think I would go for it and give it a go.

Hope this helps.

K

So I would guess (and it's only a guess so no guarantees here) that you would be fine with a larger sized unit.

 

[Bills Elm]

K

cheers for the info I feel a lot happier now and i'm gonna go for it anyway as it's my mate who's selling it and he's give me it on approval so no money lossed if it don't work out

Just hope I don't fry lol

Bill

 

[graduate_owner]

Hi again,
I forgot to mention that you will now have the immensely useful feature of variable speed, plus reverse. This Christmas I plan to get a Goliath chuck from Axminster which has left / right hand threads, so I can turn inboard, remove work plus chuck all in one, and fit to the outboard side (or vice versa). The idea is that I will have effectively reversed the rotation for finishing cuts / sanding without any risk of the chuck unscrewing from the headstock. This happened to me once with my Myford - it's a bit scary!!. Make sure you don't make the same mistake if you just reverse the direction of rotation using the inverter.

K

 

[Bills Elm]

Thanks K

I'll watch out for that!!

Bill