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Do Basic 2 Position (ON/OFF) Ignition Switches Have Voltage Requirements?


leomara

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No problem using a 12 volt ignition switch for 6 volts..

 

When the original ignition switch is missing, or the potmetal cylinder is swelling and jammed, or it's one of the type that the switch is built into the ignition coil and the potmetal housing or coil has gone bad, I have installed a 12 volt chrome plated marine ignition switch in 6 volt systems many times. Zero problems.

 

And a 12 volt switch often gives you the option of installing a starter solenoid near the starter motor and use the key start position of a three position if you have a foot starter switch that is bad.

 

Paul 

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As noted, there are two different issues, both of which effect the capabilities of the switch. Voltage rating is a function of insulation between the contacts. Higher voltage requires better insulation, so in this case the higher voltage switch is fine (and in reality most switches like this are rated at 100v or more as far as insulation is concerned). As noted above, current rating drives sizing of the metallic contacts and lower voltage systems require higher current for the same load. In this case, the 12V switch may or may not be adequate, depending on the amperage rating.

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12 minutes ago, leomara said:

Wow!  Another dilemma.  Finding a 2 position, 3 pole starter switch for 6 volts.  Sources???

 

Again, 6V is not your problem. You need to figure out the required amperage rating. It would also help to know what type of switch you are looking for. Key switch? Pushbutton? Toggle?

 

These Littlefuse key switches are available at ratings of up to 30A continuous duty.

 

https://www.littelfuse.com/products/switches/ignition-switches/956-heavy-duty.aspx

Edited by joe_padavano (see edit history)
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Hey Joe, a starter switch for a 1928 Chrysler, keyed and besides the voltage/amperage issue I want it to fit in the same place the old one did trying not to be obtrusive.  The switch you pointed me to has 5 terminals,  I only need off/on function with 3 contacts, input, output (ammeter and distributor).

Edited by leomara (see edit history)
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27 minutes ago, leomara said:

Hey Joe, a starter switch for a 1928 Chrysler, keyed and besides the voltage/amperage issue I want it to fit in the same place the old one did trying not to be obtrusive.  The switch you pointed me to has 5 terminals,  I only need off/on function with 3 contacts, input, output (ammeter and distributor).

Not knowing your requirements, it's difficult to offer suggestions. Note that you can simply not use extra terminals. My point is that there are a LOT of key switches out there. Voltage is irrelevant. Current capacity is what matters. Check Mouser, McMaster Carr, DigiKey, etc.

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2 hours ago, leomara said:

Hey Joe, a starter switch for a 1928 Chrysler, keyed and besides the voltage/amperage issue I want it to fit in the same place the old one did trying not to be obtrusive.  The switch you pointed me to has 5 terminals,  I only need off/on function with 3 contacts, input, output (ammeter and distributor).

It doesn't have to be complicated. Many of the restoration supply places like Roberts, Schnieders and others, sell universal ignition switches that fit in the same hole as originals, and they are listed for use with both 6 and 12 volt. If your not running all the electric system through the switch you don't have to worry about amp ratings. A 6 volt coil ignition system only pulls about 6 amps to start and 4 amps while running. I've run them with an Airtech electric pump on the same switch and they handle it fine.  Also, with a starter solenoid when the original foot switch has gone bad, or the owner has short legs and can't comfortably reach the foot switch.  I like the marine ones because in many of the applications I need them for, the switch hole in the dash is larger than most..... and they come chrome plated over brass.  

Edited by PFitz (see edit history)
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Only in AC switches  you will find ratings of different sizes because of voltage requirements. Most AC's carry low amps.

The DC behaves a little different. If the contacts in the switch is not adequate or the insulation is not adequate it will fail prematurely. Heavy amps in both AC and DC needs heavy duty switches. Tiny switches in electronics gadgets can carry high voltages but currents in micro amps

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Hi dodge28, thank you for your post.  However, not being well versed in electrical terminology how does this translate to my need of an ignition switch for my 1928 Chrysler with a stock wiring setup?  None of the old stock switches on ebay have voltage or amperage ratings but anything prior to the 1950's was probably made for a 6 volt system.  The new switches posting an amperage rating for a 12 volt system are usually 10 - 12 amps.  According to PFitz I should be good with any of them.

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This isn't rocket science. Don't worry what AC switches require, you're only dealing with DC voltage. And as long as you're not trying to run a lot of the vehicle's electrical system through the key switch it's fine.

 

As I said above, if you look at the replacement key ignition switches they often list the switch for 12 and 6 volt.  Here are some with just doing a quick web search for "ignition key switch". 

 

ignition key switch - Yahoo Search Results

 

These have the look of an antique ignition switch. 

 

Gardner Bender Universal Ignition Switch with 2 Keys | Northern Tool

 

Standard Motor Products US14 Standard Motor Keyed Ignition Switches | Summit Racing

 

Even Amazon carries key ignition switches.

 

Amazon.com : ignition key switch

 

Paul

 

 

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Hey lozrocks, I may be mistaken but the bracket on the steering column which holds the ignition switch is the same for your 1929 as for my 1928, correct?  If so the hole for the ignition switch on mine is 1 inch wide and 1 inch deep.  This switch which you used must have required some "work" to make it fit?

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Running a electric fuel pump on the same circuit as the ignition switch is a bad idea. It can cause running problems. Most fuel pumps draw significant amperage, and as they go bad they can draw more causing ignition issues which can be difficult to diagnose. 

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  • 3 weeks later...
On 10/13/2022 at 9:20 AM, leomara said:

Hi dodge28, thank you for your post.  However, not being well versed in electrical terminology how does this translate to my need of an ignition switch for my 1928 Chrysler with a stock wiring setup?  None of the old stock switches on ebay have voltage or amperage ratings but anything prior to the 1950's was probably made for a 6 volt system.  The new switches posting an amperage rating for a 12 volt system are usually 10 - 12 amps.  According to PFitz I should be good with any of them.

There were 12 volt systems prior to 1950.  My 23 Dodge is 12 volt.

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On 10/22/2022 at 11:36 PM, leomara said:

Hey lozrocks, I may be mistaken but the bracket on the steering column which holds the ignition switch is the same for your 1929 as for my 1928, correct?  If so the hole for the ignition switch on mine is 1 inch wide and 1 inch deep.  This switch which you used must have required some "work" to make it fit?

The switch is 19mm in diameter. The hex nut screws off, leaving about 30mm of shaft to go thru the bracket.

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