brushless dc motor conversion??

[jim]

does anyone know of a guide to upgrade a mill to a dc brushless motor??

i've been looking at the RS site, but my understanding of electricity is not great!

i've got a Weiss WMD20 mill (similar to Chester 20v), that needs sorting out!

thanks, jim

[HS93]

you need a motor and inverter to go 3 phase, if that is what you mean, I have just done it with my Lath and it is great lots of torque. I used a http://www.newton-tesla.com/machinist/index.htm  and if you ring them they may have a package that suits you.

Peter

[raynerd]

Jim, doesn`t the WMD20 come with a 3/4HP dc motor and driver board anyway?

http://www.weiss.com.cn/products/wmd20v.php

Do you mean it is broken or what exactly are you trying to do ?

You can replace the driver board I expect with something like the X2 replacement that Arc Euro stock but it is expensive at £125. Mine blew up but I managed to fix it for £1.60, which was better than a new board. I always presumed these DC motors were brushless but I could very well be wrong!! The X2 motor replacement can also be purchased from ArcEuro for £70:
http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/X2-Mini-Mill-Spares

Chris

 

[jim]

thank you for the replies

i'm looking to convert to belt drive and figure change the motor if i'm going to do it. the wonderful plasic gear went last year and i see it as a weak point.

the motor is a brushed motor and may be on its way out. Its running half as fast in reverse. ie max speed in low gear is 1350 forwards and 800 in reverse.

if i buy a DC brushless motor would my control (for a brushed DC motor) be ok???

like i say, i've not got a great understanding of electricity!!

[John Stevenson]

Running at half speed in reverse is standard on these, why I don't know but they switch a resistor in for reverse running.

The brushed DC controller will not work with a brushless motor, add to this the brushless controllers are expensive, around £200

John S.

[tonybraz]

Hi I use a brushless dc motor on my small cnc mill. I use a motor used in r/c models which has a speed controller with a servo tester to change speed. This is powered by a power supply from a computer.Have look at the picture 

[jim]

Thank you for the advice 

i've taken the motor apart this afternoon. the end (where the brushes run) was quite dirty, i've skimmed that up and cleaned up the brushes.

Thanks John, that explains about the reverse speed 

The only reason that i found out it runs slower in reverse is that, the easiest way to run a pulley would have the motor running in reverse.

more thought on my part is now required!!

[modeldozer]

For info on brussless DC motor convertion have a look at this site, apart form the parts there is a bit of info aswell
http://www.kelinginc.net/CNCmillingcontroller.html

Usual disclamer.

Abraham

[jim]

after sleeping on the matter i now realise that if i flip the motor over i can run two pulleys!

[spuddevans]

after sleeping on the matter i now realise that if i flip the motor over i can run two pulleys!

 if this is a dc motor you can reverse it very easily by just swapping over the 2 wires feeding power to the motor. (obviously leaving the earth intact)

Are you sure that you need to reverse the direction off the motor? When I did my belt drive conversion I thought that my motor needed to be reversed, but it turned out that it didn't.


Tim

[John Stevenson]

Anyone read the whole of the post in the Keeling link on brushless motors ?

Seems that there are issues with the driver boards not working.

[John Rudd]

I've just finished reading the full thread.....

Seems there are problems with the driver board that have not yet been resolved.

While it appears that resolution is close, the board may need reworking and wont be available until the year end...

That's the message I get.......

[modeldozer]

Have not been on the site for some time and only used it for information.

Here is another one directly from a manufacturer
http://www.adlee.com/brushless_dc_motor_with_ac_driver.htm

I have only used these sites for info when I was developing a low speed spindle for my router.  Allthou great variable speed propultion systems the cost in the end made me use 3phase AC with vector VFD in my design, not built yet as I am having lathe problems  .

Abraham

[jim]

after sleeping on the matter i now realise that if i flip the motor over i can run two pulleys!

 if this is a dc motor you can reverse it very easily by just swapping over the 2 wires feeding power to the motor. (obviously leaving the earth intact)

Are you sure that you need to reverse the direction off the motor? When I did my belt drive conversion I thought that my motor needed to be reversed, but it turned out that it didn't.


Tim

there are only the two wires for the motor, the earth mounting point has NO wire!!!

My sieg lathe used to give little electric shocks. it came with a funny looking plug and ran through an adapter, i changed the plug and found NO earth!!!

[jim]

after sleeping on the matter i now realise that if i flip the motor over i can run two pulleys!

 if this is a dc motor you can reverse it very easily by just swapping over the 2 wires feeding power to the motor. (obviously leaving the earth intact)

Are you sure that you need to reverse the direction off the motor? When I did my belt drive conversion I thought that my motor needed to be reversed, but it turned out that it didn't.


Tim

there are only the two wires for the motor, the earth mounting point has NO wire!!!

My sieg lathe used to give little electric shocks. it came with a funny looking plug and ran through an adapter, i changed the plug and found NO earth!!!

[spuddevans]

there are only the two wires for the motor, the earth mounting point has NO wire!!!

My sieg lathe used to give little electric shocks. it came with a funny looking plug and ran through an adapter, i changed the plug and found NO earth!!!

EEK!! Doesnt sound good. Have you a multimeter to check (with the lead unplugged to save any   ) if either of the wires going to the motor is connected to any of the pins in the mains plug? Assuming that neither of the 2 wires are connected to the mains (either live or neutral) or any metal casing, then you should be safe to reverse the wires to make the motor run in reverse.


Might be a good idea to earth the metal parts of the mill, and make a wired earth connection to both the mill frame and the mill head (dont rely on a good electrical path from just the metal to metal contact of the mill head to its column. If in any doubt, consult with a local electrician.


Tim