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toggle switches

gcom

Member
2013-03-02 9:16 am
Co. Clare
Hi All,
This is one of my first posts.
I am total novice and am building an SSE.
So - I bought myself a soldering iron, I have the board almost populated and have some drawings done for the layout.
I have been reading all the posts ( for about a year) and trying to find my own answers without asking too many questions. It is such a great forum and everyone is so helpful that I know all the answers are out there but I have bought these toggle switches from Mouser which I thought were rated at 250 volts but I see that they are rated at 250v ac and only 30v dc.

M2022B2B1W01 NKK Switches | Mouser

They are for the CBF, UL/Triode and SS/Tube rectifier.
Will they be okay?
I know that they will have a much higher DC voltage but
I don't know if they will be seeing much voltage across the actual switch.

Also, I suppose I won't be switching them live if that matters.
(from what I read here, I don't think that I will be switching them at all).
The insulation ratings seem ok.
Thanks in advance.

Some questions on the layout to come.:worried:
George
 
I'm home and I checked. I ordered Digi-Key Part Number 360-1848-ND. They are NKK and are ON-OFF-ON. I guess from my time as a switch designer for aerospace controls I got used to understanding that the safest switch for most aircraft functions was to have a complete break before make. Because of aircraft being 28 volts DC there was a better chance that contacts could weld together in make before break circuits.
 

gcom

Member
2013-03-02 9:16 am
Co. Clare
I thought I was buying on-off-on. If on-none-on means break before make I guess mine are OK in that respect plus they can't be left in a completely disconnected position in the middle. I'll check them with my dmm to see if they break first. However, it looks like they are no good to me anyway because of the 30v DC rating.
Isn't that a big difference between AC and DC handling, 250 to 30volts?

Sent from my HTC One_M8 using Tapatalk
 

PDL

Member
2010-01-06 4:30 pm
Minneapolis
I would think that as long as you don't use the switch with the amp powered up, which you should not do anyway, you'll be fine. The low dc rating is because dc likes to maintain an arc when opening the circuit, unlike ac which has a zero crossing every 120th (or 100th) of a second.

I think the CFB circuit is at a relatively low voltage to begin with, so this should be fine. The UL circuit is at a higher voltage relative to ground, but the switch only has about 30 volts across it when it is open (working from memory).

As long as you do not use the switch with the amp powered up you should be okay.
 

gcom

Member
2013-03-02 9:16 am
Co. Clare
Thank you PDL! That is exactly what I wanted to hear.
Checking the Mouser website, there aren't many toggle switches available at the high DC ratings so I imagine a lot of people care using the lower rated ones.
I promise not to play with them while the machine is turned on.

Sent from my HTC One_M8 using Tapatalk
 
The first switches I bought are DPDT ON-OFF-ON but they were not rated for the high enough voltage. I bought some other NKK DPDT switched that are rated at 250 VAC. They are much more robust. They are twice the size and the the 'bat' is about 3/4 inch long. I got the matching SPST ON-OFF switch to use as a power switch.