Artist seeks electrical advice

Yes the dimmer's in the chain of lamps. I'll be working on this for awhile yet. I've been told that the controller can handle this load, but the guy's English is not so good! So we'll just have to see.

Hi everyone, bad news this time, unfortunately. I blew out most of the string lights and apparently killed one channel of my controller. I ended up putting 12 lights into each string to make the channels even, because they weren't all lighting, and that's all she wrote. I think I need to start from scratch. I will be out of town for the next several days but will check in early next week. I did see everything work briefly though, and it really is *so* great. Worth pursuing for sure. By any freak chance do any of you live in NY? I am wondering if I am just out of my depth, and thinking it might make more sense to hire an electrician...

In the meantime, I did test one of my bulbs in a similar string of 70 and it worked. The package said to replace any bulbs with 3.5 V bulbs. And I also have found a similar light string that has all the watts/amps/volts listed. I bet I could replace my yellow bulbs in either string. The packages I bought had no info on them, and the place is out of business.

Anyway, thanks! Even if the buck stops here I am happy to have monkeyed around with enthusiastic help...

Heidi

Do you know how to connect a relay to your controller? Do you have the specifications on your controller, a url where we can find its specs, what voltage it provides, etc?

Do you want these strings to light in sequence (where S1 = string1, S2 = string2 etc) like this: S1 S2 S3 S4 on off off off off on off off off off on off off off off on repeat

or like this: S1 S2 S3 S4 on off off off on on off off on on on off on on on on repeat

In either case, how long do you want a string to be on before the next string turns on?

With some luck and ingenuity, and depending on your requirements, you could do this for under $20.00.

Ed

oops

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me

I am wondering if I am

what brand is the chase box? Chauvet? MBT?

lessee... 12 lights times 3.5V = 42 volts

120 - 42 = 78

the problem with a dimmer is 1: it has an adjusting knob which is practicly irrisistable to not adjust. 2: when adjusting with a volt meter a "true RMS" type meter is needed. 3: often RF is generated which often results in noise in nearby radios or buzz in audio systems.

lets assume for now that the current is 1 amp... that would make the lamps

3.5 watts each and the load you need to drop about 80 watts.

lets look at a transformer option. the nearest standard value would be 48 volts. a quick look on the web shows a 48 v @3a transformer for $16.95 each. that leaves 6 volts to drop which you can do by adding 2 more lamps in series per string.

Not yet...

It's distributed by a place in the Bronx but made in China. I found it online and I can get a replacement cheaper at:

If that doesn't work you can google it: RLC-737 Plus. It comes up as Chauvet on the first link, but mine is from Lighting Effects International, so it's an "LEI"

Interesting. I like #2 but I think it might be weird -- even though I have 4 channels the total height is 6 lights (meaning channels 1 and 2 are on the outside of the sunrise, as well as on the inside). But I know #1 works--at least when it's fast enough, you don't think about that. Let's say #1.

To throw something else in the mix, I'd like to light 7 more red bulbs of the same kind (on the head band) on either a separate line that's always on, or on S1 (first choice) or S4 if we go with scenario 1. Also if this is ridiculous it can be its own line. But ultimately a fog machine might be connnected and all of that would mean 3 plugs... probably too much.

Less than a second I think. 3/4 of a second, maybe? I had not really thought about this. Let me know if I have to decide.

Well that's definitely within the budget although I won't hold you to it. I talked to one guy at my favorite electrical store in Chinatown and he said I was going to need a transformer that would cost about $600 PER LINE. And that I could use a transformer from Radio Shack but there would be lots of humming. But he also told me I could not string together LEDs. So I am not following his advice right now.

Thanks! Heidi

>

I looked up the parts. They come to $21.89, but I'd opt for another ~4 dollars to accomodate the extra bulbs. That's the good news. The bad news is that's using 3 different mail order houses - which means 3 separate shipping & handling charges on top of the parts price.

I was hoping to get lucky at one of the suppliers where all the parts would be available.

And the parts price doesn't include a cabinet or any hardware or wire. Ingenuity comes into play with that - scrounging an old cabinet & line cord and having some screws and nuts on hand.

When do you need the thing?

Also, I have to believe the store in Chinatown did not undertsand what you need. 600 dollars? Sheesh! Well, mayber they are figuring the subway token to deliver it to the museum (?) on 26th street. That leaves what - $598.50 for one transformer? I'll be shaking my head for a long time over that one.

If you are interested in the parts breakdown/price, let me know and I'll post it or Email it.

Ed

Great! Yes please, let's see what all the stuff is and I'll order it. The wait is fine as I am adapting the headband piece to be a 3D ring of steel instead of a 2D piece of wood. I don't get that headband back till Wed, and then will be "rebeading" for days...and I also need to build a frame behind this whole thing for it to hang on the wall and contain the fog machine. I have lots of work to do on this, but I don't have a deadline.

I was hoping that guy didn't know what he was talking about with the $600 step down transformer, or whatever it was.

Thanks! Heidi

Ok. I made low cost the priority, followed by ease of assembly. At the end I added a couple of options that raise the cost a bit, but are worth considering.

First, we'll use the 120 volt outputs from your controller like this, one wall wart and relay per channel:

------------ Controller | ------- 120V =| 9V DC | ----- | | wall |===|Relay| | | wart | ----- | ------- RLY-426

------------ DCTX-915

Above parts are from Allelectronics: DCTX-915 4 @ $2.50 = $10.00 RLY-426 4 @ $0.75 = $ 3.00

you'll want a perf board to mount the relays - something I forgot earlier. Thats another $2.00, catalog # PC-4 from them.

Next, we'll use a 24 volt, 4 amp transformer like this:

------------ |Transfromer |-----> To string 1, 2, 3, 4 and 5 common

120 ---| 24 V | VAC ---| 4A |--- no connection | #7845 TR | | From MPJA |---+------ Rly 1 contact ------------ | ^-------> To bulb string 1 | | +------ Rly 2 contact | ^-------> To bulb string 2 | | +------ Rly 3 contact | ^-------> To bulb string 3 | | +------ Rly 4 contact | ^-------> To bulb string 4 | | +-------------> To bulb string 5

The transformer is part # 7845 TR at $8.49 from MPJA

's an upgrade from the 2 amp transformer, and will support the additional string of 7 bulbs.

Next, the bulb strings and resistors:

String 1 ---+---[5ohm]---[1.5ohm]--B--B--B--B--B---+ | | +---[10ohm]------------B--B--B--B------+ | | String 2 ---+---[10ohm]------------B--B--B--B------+ | | +---[10ohm]------------B--B--B--B------+ | | String 3 -------[5ohm]---[1.5ohm]--B--B--B--B--B---+ | | String 4 -------[10ohm]------------B--B--B--B------+ | | String 5 -----------------------B--B--B--B--B--B---+--- Common

Resistors:

2 @ 1.5 ohms, 5 watts p/n 280-CR5-1.5-RC $0.39 ea $0.78 2 @ 5 ohms, 10 watts p/n 280-CR10-5.0-RC $0.55 ea $1.10 4 @ 10 ohms, 15 watts p/n 280-CR15-10-RC $0.63 ea $2.52 Total $4.40 from Mouser Overall total: All electronics $15.00 MPJA $ 8.49 Mouser $ 4.40 ===== $27.89

Ok at that price there are 2 questions: First, and most important: can you wire this? Second, can you spend a little more? Remember, there will be 3 shipping&handling charges added.

But I would highly recommend a few simple additions:

1) You must add a fuse in line with the 120 volt power to the MPJA transformer. You may also want a switch. A 2 amp fuse and a fuse holder: holder # FHPM-47 $1.00, fuse # FS-2 5 for $0.75 from Allelectronics An MTS-4PC toggle switch is $1.00 there.

2) It would be a good idea to reduce the voltage slightly - that will protect the bulbs a bit. Adding a .5 - 1 ohm resistor to each string or sub-string consisting of 4 or 5 bulbs will reduce the voltage to each bulb by about .2 or .25 volts for the 1 ohm or about .1 or .125 for the .5 ohm. I would order

6 of each 280-CR5-0.5-RC and 280-CR5-1.0-RC. At 39 cents each, that comes to $4.68. You can then experiment to see if the bulbs glow brightly enough with a 1 ohm resistor added to the group of 4 or 5. If they do, use that resistor. If not, try the .5 ohm resistor. This requires the artist's eye. The "engineering eye" wants the bigger resistor. :-)

3) There will be a short delay between the time your controller switches a channel off and the time the lights turn off. The simplest way to keep that delay short is to add a 100 ohm resistor in parallel with the relay coil. 282-100-RC at 19 cents each from Mouser will total 76 cents. It may be a worthwhile addition.

The relay wiring requires that you are able to determine what pins on the relay are the coil, and what pins are the contacts. Do you know how to do that?

Ed

in the past I have modified these low cost chase units to us low voltage. it take only one transformer and you merely cut the 120 VAC source to the internal TRIACS and replace with the lower voltage transformers secondary. unfortunately this pretty much violates whatever UL rating, therefore it was for my own amusement in creating a disco chase with 24 volt mini par cans.

another option would be to rewire the light zones to series-parallel in groups of 2 lamps and use 6 volt transformers, one per output. these are commonly used in PAR 36 pin spots.