Switch & Fuse for 12A @ 110V?

[SteveHGraham]

I thought getting a big power supply was a good idea. Now I see that this thing sucks up 12 amps at 110V, in spite of the fact that only 600 watts (12 amps x 50 watts) come out the front. My wall voltage is 125, so I assume the current will be somewhat lower. I don't really need 48 volts, so I'm going to turn it down as low as possible.

Can someone recommend a good switch? I was going to pop a Carling switch in there. This is a toggle commonly used on guitar amps. The current rating is 3A, so I don't think it will work.

Fuse advice would be nice, too. There is a lot of inrush current. I assume a slo-blo is the way to go, but I don't know how choose it. I'm sure it has to be higher than the rated 12A.

[hammermill]

not sure but the calculator may need some sun light 12 amps at 120 volt comes out to 1440 watts.
an substansional amount of energy. could you be confusing primary and secondary??

yes I would use a switch with a higher rating and a slow blow fuse. also

[SteveHGraham]

You have hit upon the thing that did not occur to me. The output is enough juice to produce 600 watts (12.5A @ 48V DC), but apparently the thing requires 12 amps of 110-volt power to produce it, so about 800 watts are wasted as heat and fan power and so on.

[SteveHGraham]

It looks like Mouser has simple toggle switches that will handle 20 amps. Surely I don't have to use something complicated. A 1500W hair dryer doesn't require a magnetic starter or anything crazy like that. The Mouser site is acting weird, so I guess I can get one locally. Home Depot sells 12/3 extension cords. I'll have to cobble some kind of strain relief together. I guess I'll try a 15A slo-blo and see if I stall the local nuclear plant.

Sometimes I really wish I had studied engineering instead of physics. I think even DeVry would have been better. I had a grand total of one course that taught me anything practical.

[hammermill]

That is unbelievable inefficient. I would figure 10 percent. 660 watts in. 600 watts out. How about a link to the supply

[SteveHGraham]

Well, here is the problem. The site where I got it does not list the current draw. I had to go on Ebay, find similar Chinese power supplies, and look at their specs.

Here is the site where I got it: http://www.automationtechnologiesinc.co ... -duplicate

Well, now I feel stupid. They do have some downloads, which I am now searching.

[SteveHGraham]

The PDF says "7A," but it doesn't say which input voltage. The range is 100-240. Obviously, it can't draw 7A at every voltage level.

http://www.automationtechnologiesinc.co ... ion?did=53

[schor]

I buy simple motor starter toggle switches that are rated for 110-240 15-7.5 amps rated 1hp usually. Those should do the trick. I get them at princess Auto up here, but most any electronics store would have them, possibly a marine supply place.

I thought getting a big power supply was a good idea. Now I see that this thing sucks up 12 amps at 110V, in spite of the fact that only 600 watts (12 amps x 50 watts) come out the front. My wall voltage is 125, so I assume the current will be somewhat lower. I don't really need 48 volts, so I'm going to turn it down as low as possible.

Can someone recommend a good switch? I was going to pop a Carling switch in there. This is a toggle commonly used on guitar amps. The current rating is 3A, so I don't think it will work.

Fuse advice would be nice, too. There is a lot of inrush current. I assume a slo-blo is the way to go, but I don't know how choose it. I'm sure it has to be higher than the rated 12A.

[SteveHGraham]

Thanks. If it works for you, it will work for me.

[hammermill]

Ok so it draws 7 amps at110 bolts. It should half that at 220. A10 amp switch will be good

[SteveHGraham]

How do you know that rating is for 110?

[hammermill]

I will based on years of experience,

a better explanation is except for some minor losses the same watts out should equal the watts needed to be input.


using ohms law power is equal to amps times current p =I x e

48v x 12.5 =600 watts

600 watts divided120 volts equals 5 amps and I added 2 amps for unknowns like fans

600 watts divided by 240 volts = 2.5 amps