wire for power - size, twisted, etc.

[musika]

Hi all,

I am replacing some wire that is from my console connector - it carries 24v, 48v, and ground obviously. I have some silver 19 strand 22 awg that I am thinking will be ok, but the wire size I am replacing is quite heavier and is not shielded, but jacketed. This question applies to all diy projects I guess. I've seen a lot of occasions where the power wire is twisted.  Does this make a difference?

Any comments ... please

 

[JohnRoberts]

Yes it all matters,,,

Basic relationship is wire resistance per foot? how many feet? How much current? And how much voltage drop do you consider acceptable (based on good old Ohms law?

Twisted vs straight affects magnetic fields generated and picked up, as well as proximity affects capacitance.

JR

 

[Brian Roth]

22 AWG is likely much too small for the DC leads connecting an external PSU to a desk of just about any size.  Do you know the DC current being carried to the desk...and how long the cable needs to be?  The wires will likely need to be a minimum of 18 or 16 AWG, or even much larger, depending on current drawn and cable length.

Best,

Bri

 

[musika]

Thanks Brian,

The wire length from the socket to the backbone connector is about a foot.  I do know the DC current - it's 24 volt.  And there is a separate 48 volt for the microphone phantom power.  So it is a three wire/pin connector.  Based upon what you say, I can use 12 AWG stranded and be better off for that. 

David 

 

[Brian Roth]

I think I may have misunderstood the original posting.  It seems the wiring to be replaced is within the desk, from the external connector to the "motherboard", and not the "snake" wiring which travels from the desk to an external power supply unit.  The latter cables are often many feet in length, and thus need to be thicker to minimize voltage drop down the length of the "snake".

24 Volts tells us one thing about the supply, but the DC current (specified in Amperes) is a separate parameter.  In general, the more Amperes of current flowing through the wire (and the longer the wire length), the the thicker the wire needs to be to minimize the voltage drop down the wire's length.

I would think 1 foot of 12 AWG would be sufficient for MOST (but not all) desk applications.  I assume it will be possible to physically solder the 12 AWG wire on both ends.

I know the huge Amek 9098 series desks used DC powering cables which looked like automobile battery cables!  But, each section of those desks drew many Amperes of current.

Best,

Bri

 

[musika]

Brian,

Well, I did understand, and then I didn't .... so thanks for the clarification.  I know that you have built a console from scratch many years ago, and I'm very appreciative of your understandings on this matter.  I'd like to email the documentation that I have on this console - an A&H MOD2 16x8x16.  I didn't see any specifications for dc current in amperes.

There is a external 5u external power supply which has 2 fairly heavy supplies on it - a 24 volt and a 48 volt. The power cable to AC is not grounded.  I think the 48V supply is a Lambda.  A 3 wire cable is twisted and jacketed and is about 15 feet in length probably 18 AWG and stranded.  It connects to the master monitor module.  The underside of this connector then runs about a foot in length to the 3 blades of two McMurdo (UK) 10 pin connectors on this Master module carrying 24v, 48v, and ground.  There are 2 PCB cards on this module.  The length is about 1 foot from the underside of the connector to the 2 McMurdo multipins.

David