Re: what size motor do i need

Dave,

Don't go with Zeners, or other methods of reducing the voltage at the
output (Transistors, resistors etc). The power that you will have to
dissipate is the square of the current times the voltage. For a 10
amp supply this works out to 3000 Watts. If there are transformers
in your power supply, replace them with tranformers with a 30V AC
secondary. This will give you the required 40V, without the heat and
electrical bill.

I'm using Hammond 165S30's in my Power supply (Mouser, DigiKey, and
Electrosonic sell them)

Tony


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "dscott488" <dscott@i...>
wrote:

> I am a newbe. I have done some reading and have a router/plasma

table

> almost done it will be driven by 424 oz in 34's geckos and deskcnc
> controller board. I have two question the, the first is about power
> supplys I have the amps needed but too much volts 70 I only need 40
> can i put a zener on the thing to reduce the voltage? the second

has

> to do with the motor torque requirement. I questimated at the

needed

> torque, but the more i read the more im convinced that I may need

to

> bite the bullet and buy the (right motor) for the table. the table
> moves and is heavy. I have an accurite fish scale and it says that
> the it take 9lbs to get it moving and 8 once its going. that is

with

> the motors connected to the tabel through a belt. I have know way

of

> knowing the additional torque required to cut brass of aluminum.

can

> any you calculate or give me your best guess for the motor torque
> required.I have looked over the setup page in desk cnc and have no
> idea about motor speeds or step proccessing any help on that would
> also be greatly apriciated.
> Dave Scott