CAD CAM EDM DRO - Yahoo Group Archive

Re: Re: Controlling more stepper drivers than I have outputs for?

Posted by beer@s...
on 2002-04-15 10:30:21 UTC
On 15 Apr, CAD_CAM_EDM_DRO@yahoogroups.com wrote:
> From: "dave_ace_me" <davemucha@...>
> ummmm,
>
> there has been talk about using a relay to switch the output of the
> controllers. This is a no-no as power loss can be pretty great.

Care to elaborate ?

For example, I took my controller, running 50 volts and probably never
more than 10 amps, worst case.

I then looked at the inexpensive P&B relays I used, rated with a contact
resistance of 75 milliohms.

At 10 amps, that's 7.5 watts of power, admittedly a large figure. But
it's only 1.5% of the total power going out .. a figure I can certainly
live with, considering the safety implications of not having relays.

At the more reasonable ( for my setup ) 5 amp figure, the power lost in
the relay is under 2 watts and total loss is under 1%.

One percent I can ignore.

Alan

--

Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta

Discussion Thread

beer@s... 2002-04-15 10:30:21 UTC Re: Re: Controlling more stepper drivers than I have outputs for?