Electric Speed Variator 3 Phase question.

[miker]

Could anyone tell me what size horsepower motor this would drive please.

http://cgi.ebay.com.au/Electric-Spe...yZ105827QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I am assuming I could just wire this box between the 3 phase power outlet and my mill or other 3 phase machinery and vary the speed.

 

[AllThumbs]

1 to 1.5 HP (750-1000 watts)

What is it you are trying to do?

E

 

[miker]

Thanks for the reply AllThumbs.
I am rebuilding a very old (1939) Fray Mill and it is belt drive with a 1/2 horsepower 3 Phase Motor. I thought that if I could insert the speed variator box between the mill and the 3 phase supply in my shed, I would have variable speed without having to continually change the belt/pulley combination.

My 12 x 36 import lathe has the typical 2 horsepower (little Chinese horses I think) single phase motor that suffers from the usual "cogging" effect.
I was thinking of changing the motor to a good quality 3 phase one and also using the speed variator to control the lathe speed.

My thinking was that a 1-1 1/2 horsepower 3 phase motor could replace the chinese 2 horsepower rated single phase motor.

Am I way of course in my thinking?

 

[millwrong]

Be careful about assuming that the formula 750 watts equals 1 hp. applies to electric motors. You'll find this isn't the case. Select your preference for the motor from a manufacturers website, then find THAT motors max. amperage and see if your VFD can provide the necessary current.

 

[AllThumbs]

The thing is rated 1500 watts, thus the conservative estimate. Of course you should check the name plate data on the motor to be sure as millwrong pointed out. There should be a FLA (full load amps) on the name plate. Make sure it is under 2.2 A.

That said I run a 1.5 HP VFD on my 2 HP cnc'ed mill/drill and it's working like a champ. I suppose my mill-drill is now officially only 1.5 HP. It's perfectly safe, because the VFD faults if subject to overcurrent.

Eric

 

[miker]

Thanks for all of your replies.
I am now a lot better informed and will look at avilable motors first.