Thread: Just a question on the AL540 Lathe From H&F

Hi Colbra,
The 3 phase lathes will have a two speed motor.(I can only assume a single phase motor cant easily be made two speed as I dont recall ever seeing one.?)

If the lathe was manufactured in Taiwan I'm pretty sure H&F would be saying so.

Can't help any more than that, never even layed a hand on one.

Stuart

Hi Stuart
Thanks for replying to my inquiry on the H&F lathe I tend to agree with you after looking in there catalog all the machines that are made in Taiwan have it splashed in red across the front on the advertisement of there product. On that subject I was talking to Dave the other day and he was pretty disappointed in the Taiwanese machines in general.
The other thing once you get into the bigger machines around 7hp 20 to 25 tool height they all seem to be made in Taiwan and cost around ten to twenty thousand dollars not the sort of thing for a want to be back yard machinist on a budget.
The two speed 415 volt motors are something new to me I will read up on that its all new ground, I may not be even able to understand it all that well, I know AC theory gets a bit deep and I no nothing about two phase electric motors.
Thanks again Colbra

Originally Posted by Stustoys

Hi Colbra,
The 3 phase lathes will have a two speed motor.(I can only assume a single phase motor cant easily be made two speed as I dont recall ever seeing one.?)


Stuart

Two speed (or more) AC motors are not uncommon. Some washing machines use them. They simply tap into the field windings at a midway point.

The downside is that the power drops with the speed.

Handy for things like buffs and linishers where power is not an issue.

Rob

Originally Posted by colbra

Hi Stuart
On that subject I was talking to Dave the other day and he was pretty disappointed in the Taiwanese machines in general.

Thanks again Colbra

Hi Col,
When we where talking the other day it was the H&F Chinese quality in general, not the Taiwanese (I cant afford the larger Taiwanese machines, LOL)

If we don't find a problem with your lathe, the AL540 is just a bigger version of yours. It's pot luck what you get from H&F I find. They just don't have the quality to be able to open up the crate and know you got a good lathe, it takes checking it over to see what you have to work with.

As others have said the 3 phase lathe have 2 speed motors in them.

Dave

Hi Rob and Dave thanks for that bit of information Rob, it would be a steep learning curve for me to go into the theory of AC and electric motors.
Sorry about that Dave I got things a bit mixed up again. I am sure we will get to the bottom of things when we catch up in a couple of weeks.
I too have found that with Chinese tools from H&F as well as Carba- Tec, it appears to be the luck of the draw I just wish I could get lucky with some of my purchase from time to time at these places.
I agree with you it would appear to be a similar machine but larger with more bells and whistles and at the end of the day what is the use of all the bells and whistles if the back wheel is missing LOL
I like to get the catalogues look every thing up and just dream a bit what I would do if I won lotto or robbed a bank!... LOL.
I wonder if anyone on the forum has the AL540 lathe they could give me some input on the machine.
You Blokes have a happy new year and stay safe on the roads if you have to travel
Colba

Hi Col,
No worries. There are at least 2 forum members with a AL540, but they might be on holidays.

Dave

Thanks Dave.... getting away from things a bit.......when you came back to me just then I was buying some metal wheels, I had made a router lifter out of a scissors jack as well as that I made the same type of lifter for my scroll saw table so I could push it around here is the eBay site
eBay Australia: Buy new & used fashion, electronics & home d

Col

Colbra, some basic AC induction motor theory for you.

Induction motors run at near fixed speeds, detemined by the input frequency and the number of magnetic pole pairs they are wound for. They have a rated speed slightly lower than the theoretical speed because they 'slip' a little to produce torque to drive a load.

Nominally the speed is F x 60/Pole pairs where F is input frequency (cycles per second), and 60 converts seconds to minutes. So for a 50Hz supply and 2 pole (1 pole pair) motor the nominal speed would be 50 x 60/1 = 3000RPM. At rated power the slip would reduce the rated speed slightly to typically 2850 RPM (5% slip).

To vary the motor speed, you either vary the number of poles in the field windings, or vary the frequency with something like a VFD. Common winding arrangements are 2 pole as above, 4 pole 1500RPM nom, 1440RPM rated (typical) and 6 pole 1000RPM nom, 960 RPM rated.

The above applies to single phase or three phase (415 V) motors equally. It is easy arrange switching so that the number of poles can be controlled.

However, a single phase induction motor does not now which way to turn, and has very little starting torque, unless it is fitted with an auxilliary (start) winding, energised via a capacitor and centrifugal switch. Once the motor reaches about 80% of rated speed the centrifugal switch opens its contacts disconnecting the auxilliary winding (or significantly reducing the current flowing through it in the case of a cap start/cap run motor). However the only way to make a successfull multi speed single phase motor would be to include multiple centrifigual switches (one for each speed selection) making the motor and switchgear more complex and expensive. The same issue precludes the use of VFD technology to control the speed.

These factors are not an issue to 3 phase motors as they have far superior starting characteristics and the direction of rotation is determined by the phase sequence of the supply. They do not need the auxilliary winding, capacitor and centrifugal switch, and can be switched for two speed operation quite easily.

Hence it is viable to offer two speed motors for 3 phase connection, but not viable for single phase units.

Thank you Malb for replying to my question on AC theory of an induction motors as I read through your detailed explanation on things, I must say it is a little beyond me to understand in great detail and there would be many questions that would come to mind… but just for the fact you have explained it so well I will study up on things to understand more about it. The ordered movement of electrons is certainly a fascinating topic in every sense of the word.

Thanks again Malb and have a happy and safe new year Col

G'day there,
I have an AL-340
I am really quite happy with mine, I didn't even get the manditory casting sand in my gear box
Believe it or not straight out of the crate I found the bed to be free of warp and twist and the castings to be in good sound condition.
1 of the small issues I did have and you will probably find it with all the Chinese machines, is the backlash on all axis had not been adjusted at all.
And the tailstock was out by about 2 thou, Which was as simple as a quick adjustment.
So all in all I am quite happy with mine.
My machine would be 5 years old now so maybe the quality was a little better back then but I highly doubt it..
I do believe one of the best mods I have done though was installing a DRO. And the next new machine I buy I will take the DRO option from the factory, Just because it saves a little time stuffing around fitting one up.
I am thinking about looking for a larger lathe at the moment to compliment the AL-540. I would like something with 2 meters between centers..
Anyway I am wandering....
If you want to know specifics just ask mate.
Matt