Folks
For the elecrically inclined, a very basic qustion?
How does one convert an AC switch rating to the DC equilivent.
For example 125V AC 3-amp relates to 12V DC at what amps??
I know DC ratings are less for a given voltage due to the one way current
gradually removing metal from one contac
: KRnet
Sent: Friday, December 19, 2003 02:57
Subject: KR>Switch ratings
Folks
For the elecrically inclined, a very basic qustion?
How does one convert an AC switch rating to the DC equilivent.
For example 125V AC 3-amp relates to 12V DC at what amps??
I know DC ratings are less f
John,
The exact number varies with the construction of the switch, but a rule of
thumb is that the D C current rating is about 1/8 that for A C.
As the switch is closed or opened, there is an arc as the contacts separate.
Since A C reverses itself 120 times a second, the voltage passes through
Yikes
Thanks Jim
But does the 1/8 rule apply to unequal voltages?
Would 125 VAC 3 amps really equate to 12VDC 0.375amp!!
Is this really correct?
If so, my ignition switches are about 8 times under rated for my Bosch 3 amp
coils and most of my other swirches are suspect as well! Off to Aeroelectric
But does the 1/8 rule apply to unequal voltages?
>Would 125 VAC 3 amps really equate to 12VDC 0.375amp!!
Watts are volts X amps. You are talking 375 watts (AC) vs 4+ watts (DC).
You went the wrong way way with the 1/8.
Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
lar...@socal.rr.com
bin.
See Ya
The Martindale Family
29 Jane Circuit
TOORMINA NSW 2452
AUSTRALIA
phone: 61 2 66584767
email: johnj...@chc.net.au
- Original Message -
From: "larry severson"
To: "KRnet"
Sent: Saturday, December 20, 2003 11:35 AM
Subject: Re: KR>Switch Ratings
One thing to remember is that an amp is an amp regardless of the overall
circuit voltage. If a switch is going to get hot at 1 amp in a 125V AC
circuit it will also get hot at 1 amp in a 12V DC circuit.
So it's probably safest to look at current capacity and voltage as
separate parameters when sel
>One thing to remember is that an amp is an amp regardless of the overall
>circuit voltage. If a switch is going to get hot at 1 amp in a 125V AC
>circuit it will also get hot at 1 amp in a 12V DC circuit.
+++
It would appear that several po
Martindale said;
curious about what is causing
my 1/2 volt drop across the switches... maybe they are arcing internally and
building up a resistance or maybe they're just dirty...either way as Jim
suggests, they're headed for the bin.
Preindication of failure, either in the switch or connections l
> Hi Larry
>
> Yeh that's what I thought but something still niggles.
>
> 125VAC at 3 amps should be roughly equilvalent to 14VDC at 27 amps. I
ought
> be OK but somehow the latter seems excessive?
>
> 125VAC at 3 amps relates to 125VDC at only 0.375 amps by Jim's rule of
> thumb, that is, voltage
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