switch rating question

starhawk

[H]F Junkie
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Oct 4, 2004
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Bought a switch at Radio Shack. RS Cat # 275-0015 on the bag.

Switch is actually a Shin Chin R13-268, "datasheet" page here --> http://www.sci.com.tw/PRODUCTS/switch/(R13) ROCKER SWITCH/R13-268.htm

Rating, per page above and markings on the switch, is 16a 125vac / 10a 250vac.

I'll be using it at 125vac.

I'm rebuilding a retarded and delusional space heater (one of those stupidly overcomplicated "digital" ones :rolleyes: ) that is very quick to heat up a space and very slow to realize that it's overdoing its job... the current to the elements (2 @ ~700w each -- 1500w total for the unit) is about 6a per element, and I'm planning on one element per switch side... but there's this nifty bit of surge current when it cuts off that I'm not quite sure how to calculate and I want to make sure it won't ruin the switch...

Basically --

20v supply --> old wall thermostat --> relays+125v supply --> heating elements

The relays are 24vdc-coil models that have a min cuton voltage of 18v. I'm repurposing a very old Dell power brick that probably won't even notice the load... altho I may get 12v relays from a friend, and then I'll use a smaller wall wart if I have one that's regulated...

The thermostat is rated 24-30vac (oddly, to me) but I talked to both an HVAC professional that I trust, and the owner of the local Radio Shack (a franchise store with a small electronics repair side-biz), and both said that the thermostat (mercury bulb style) will handle DC just fine.

Having said all of that, what I actually want to know is: given that this particular switch (the Shin Chin / Radio Shack one I was talking about in the beginning) is a DPST model, is the rating total for the entire switch (so ~8a per side at 125vac) or is that total per side (so the switch can actually handle a total of ~32a at 125vac)...? Also, would the momentary surge current from the elements in the heater be enough to make it fail?
 
I'm not 100% sure, but I'd be willing to bet the 16A is per pole, not a total for the switch. The surge current shouldn't be a problem--worst-case scenario, you get a momentary arc as the switch breaks contact, and the worst thing *that* will give you is buildup of corrosion on the contacts inside the switch.
 
It won't weld the contacts together?

Continuous current is going to be 12a to 12.5a across the switch, total.
 
One other thing. Decided to get some relays from a friend, all 12v. I've got a wall wart here rated 12v 1.25a (way beyond overkill but I didn't have much choice ;) ). It's an LSE9801B12, heavy as a feather and with a ferrite toroid a couple inches from the barrel plug -- and my analog multimeter says it gives out ~10v (might be as low as 9v) no-load.

Is that a regulated supply, perchance?
 
One other thing. Decided to get some relays from a friend, all 12v. I've got a wall wart here rated 12v 1.25a (way beyond overkill but I didn't have much choice ;) ). It's an LSE9801B12, heavy as a feather and with a ferrite toroid a couple inches from the barrel plug -- and my analog multimeter says it gives out ~10v (might be as low as 9v) no-load.

Is that a regulated supply, perchance?

Rank amatuer here but i'd suggest snagging a case fan or three to hook up to it and measure the voltage then. If it really is 10V then the lower power won't hurt the fans.
 
That's a good thought -- and that's probably about the same amount of juice that a pair of relays will be pulling from it (very very little!). I'll see if I can't rig that up later today.
 
"Heavy as a feather"? Don't count on it giving anywhere near 12V @1.25A, then. Lightweight wall-warts are almost always way over-rated.
 
It needs to be able to supply maybe 100mA ;) two relay coils and whatever is lost in the mercury switch in the thermostat is it.
 
Haven't done the fan test yet, although I'm about to... another quandary has arisen, however.

Relay pinouts.

My friend sent me two relays marked as below. I know they were salvaged and that's all I know -- that, and there are NO datasheets on the Net at all AFAIK.

YOUNG REEM
TYPE CS-1PD [symbol that looks like a sailboat]
COIL DC12V [dc symbol] K [cursive lowercase "L"] 1 [Underwriters' Labs logo]
16A 250VAC [SA-in-a-circle logo]
T80 308S KOREA

The relays have two spade terminals on top, and four PC terminals. Two of the four PC terminals, opposite the side with the spade terminals, have a weak connection according to my multimeter so I'm assuming that's the coil. None of the other terminals connect with any other terminal.

I'm GUESSING that means that it's DPST with one PC pin and one spade terminal per pole... but I'm not 100%.

My other option, should either of the two mystery-meat "Young Reem" relays not work (or should it prove impossible to divine a pinout for them) is to use one of two other relays for both elements. I don't think the Song Chuan 888HN-1AC-F-V (one of the two) will work for this, since its got a max switch current of 17a -- and that's without a hole in the lid (which it has, not sure how...). That leaves the TYH aka HG brand HG-4115-012-HC. It's open frame, but it can handle 30a... not sure I like the "open frame" part tho, since this is for a heater that will be used in a bathroom...

Worth noting re: location -- I have a pair of inexpensive sealing food containers, one of which will be used for this to keep water vapor from tinkering with the electrics here... basically I'll put the electric bits inside, seal all holes with hotglue (provided one of the two or three hotglue guns in the house still works) and the lid will be kept handy for shower-time.
 
Dunno how I missed this post...

I'd bet that the two spade terminals are the contact side of the relay, and the two extra PC pins are some sort of auxiliary contacts. I say hook the coil to a power supply, and see which pins show continuity.

Oh, and pics would be most helpful.
 
My multimeter is out of action until Thurs at the earliest :( after six plus years of service the probe wires are shot. I'd rather not ghetto rig a continuity tester...

Pic --> http://i.imgur.com/dR1VdNk.jpg
Done as link because HUGE PIC. (You've been warned. Prepare your modems :p )
 
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