# Blew them up really good this time



## ship (Mar 18, 2004)

I was working with my brand new extreme output 100w/12v PAR 46 lamp today for a minute or two. Had a great resistance dimmer that I could adjust with a multi-meter to the exact voltage necessary to safely optimize the lamp and all was going to be good.

Got out my figure 8 multi meter accessory so I could meter the voltage, and multi-meter and plugged them in line with the lamp. Away I go. One volt, two volts, three up to seven volts... ten volts... ten volts... ten volts, than sudenly 0 volts after a quick peak in voltage.

I look, think a bit, answer a phone call than "#%[email protected]," I was using the amp clamp instead of the voltage probes. Got up to tem amps and no matter how many volts I put into the lamp it was not about to get up higher. Hello, the meter was set to amperage reading and hooked around the figure 8 tester, and what you were attempting to read voltage. There goes $19.00. The replacement lamp I'm going to get my rear chewed about will be in Monday. The designer will be there to see it on Thursday - in the morning tomarrow. Never even got to look at the beam, my focus was on the voltage... er Amperage.

Later:
Than I blew up a perfectly good Mac 2000 wash fixture. Yep, my figure 8 and multi-meter again. Seems the moving light people were trying to figure out the correct amperage of the fixture. I made them a test wire for doing this but somehow the three Ideal clamp meters were showing 6 volts... er Amps more than the analog meter and Craftsman meter. Only had 20 amps available and needed to know the operating and start up amperages. Could have got a manual but who thinks of such things.

I was asked in to solve the problem with the different readings so I decided to do a more accurate test. The Figure 8 when converted by way of 208v plug to stage pin. Stage pin to Edison. Edison figure 8 back to edison. Edison to stage pin. Stage pin to 208v. Had to lift the ground in doing this and because the figure 8 did not grip very well I was in the process of taping the connections when suddenly of two fixtures twofered together one of them went poof in a flash of light. We thought it was the figure 8 which is basically a plastic wireway in that shape that allows you to safely clamp a multi-meter amp probe around a two wire circuit. The intent was to use the x10 factor on the clamp to ensure the low amperage was closer to the 200 amp setting thus more accurate.

There was a flash of light most and I thought was in a plug or at the figure 8. Egg on me, thought I blew up the figure 8 in front of a croud of people by doing something it was not rated for. Nope it worked still as tested on a 300w lamp showing that it was safe and both the Ideal meter and analog meter were measuring the same amperage.

One fixture worked, the second even when the twofer was removed did not work when plugged directly in. Checked the fuses, the plug, it's circuit board, even the lamp. The fixture would not turn on much less strike the lamp and none that worked moving lights could figure out why. Guess the moving lights crew chief is going to be a little pissed and I'm going to be banned again from moving lights. he he he.

We kind of figured out an hour later that since the Ideal clamps have peak hold and they must have measured the fixtures when they strike the arc with the hold on. The Craftsman and analog meter do not thus the difference in readings and why they asked for the better meters in the first place. All Ideal meters read the same amperage as with the analog and Craftsman. That's simple enough to explain why they would agree in amperage a few minutes later with a lower amperage and with the figure 8. Once you turn the meter off, the peak hold goes off. When I saw the meters all of them were on still. I presume that they forgot to release the hold.

Still don't know what happened to the second of two fixtures on a twofer or why it also did not take out the first fixture given the figure 8 - designed for 120v, did not take out the other fixture but seemingly it did or the on and off flickering while I was taping it up caused the problem.

In any case, even on a good day - bought about $5K worth of lamps, $2.5K worth of gaffers tape, fixed a bunch of stuff and started a 2Kw Scoop re-wiring project. Still between all the stuff going on I made too big goofs. And the moving lights head will not be a happy camper in the morning - he he he again. I thrive in driving him crazy so that's not an entirely bad thing. Competing departments/crew chiefs we are. He makes work for me, I make work for him. This time I gave him a puzzle to work on.


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## Mayhem (Mar 18, 2004)

Just goes to show that we are all human Ship. Goof's are only stupid if you do not learn from them. 

I am assuming that you are using the figure 8 cable so that you can split them between source and load to attach the clamp meter to the active? 

Oh well - hope you have a better day tomorrow.

Cheers.


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## avkid (Mar 18, 2004)

i havent blown anything yet


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## ship (Mar 18, 2004)

Blew them up really good
It was a power supply. I’m told it was a thousand dollar problem to correct. Still one still working and one not means to me I did them moving light guys a favor. I made apparent a moving light with a power supply that was about to go as opposed to it happening on tour. Thy should thank me. Instead, yep I’m banned from moving lights.

On the other hand, the meter question was it appears operator error. A 1200w and 600w PAR 64 lamp were metered amongst many meters today and all were accurate. Someone must have either had the peak hold on or something strange going on.

The figure 8 is a store bought thing to clamp the amp meter on. It has a normal slot to clamp on or a times 10 the amperage slot for more accurate readings. Not sure how that loop works or what effect it would have on two not just one leg of power but I assume it was more me plugging in the tester and it not fitting well in it’s connector thus going on and off a lot rather than any current induced loop from the tester.

As for good day, 11 out of 43 Scoops re-wired today. Three more to go and the rest are out on a show. After that it’s a question of getting back to cyc lights and lamp bars. Plus the stack of multi-cable to work on. Lots of stuff to do always.

Blowing up stuff happens if not now, eventually. When I was a carpenter I used to kill off at least one power tool a year but more likely two. The question is what caused it and how safe you made your power supply should it happen. If those questions are covered than blowing something up is no more than, gee I screwed up. Guess I’ll have to be more careful next time.


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## Joren_Wendschuh (Mar 19, 2004)

ship said:


> Blew them up really good
> It was a power supply. I’m told it was a thousand dollar problem to correct. Still one still working and one not means to me I did them moving light guys a favor. I made apparent a moving light with a power supply that was about to go as opposed to it happening on tour. Thy should thank me. Instead, yep I’m banned from moving lights.
> 
> On the other hand, the meter question was it appears operator error. A 1200w and 600w PAR 64 lamp were metered amongst many meters today and all were accurate. Someone must have either had the peak hold on or something strange going on.
> ...



Ship... Im taking a huge mental leap right here, but from my reading over the last few years, my knowledge from other sources, and what have you, I THINK I might just be able to figure this out for you.
Figure eights, the amperage meters, take ONE loop of the SINGLE PHASE hot through the '1x' loop, and ten loops through the '10x' loop, essentialy making one half of a transformer, inline with the load, that you can then tap off of with your clamp meter (the core and windings on the clamp meter completeing the transformer)... The neutral of the single phase figure eight, is then just a straight through run of wire. 
Im thinking, when you;re doing 2 hot type stuff like ths, you might need to use TWO figure eights, one on each hot, and ignore the neutral wires in the figure eight... it could be (my leap of faith here) that the induction caused by the loop of wire/clamp meter attached to it, one one leg of the feed line, without another canceling out induction on the other hot leg, could have produced a much higher voltage as seen by the happy intel light, because of the phase shifting of the 'sin' wave...
If I do the math right here... An inductor creats a 90 degree phase shift on the power line, depending on which two legs of a 3 phase supply you were using, that could bring the two peeks of the hot lines, together by 90 degrees, making them seperated by only thirty degrees, as opposed to 120 degrees, as a 'regular' unchanged supply would be... their two voltage peeks coming much closer together, casuing instead of only 208v, but something much higher, possibly 240, or even higher... its way to early in the AM to be doing any serious math... 

While the one PSU might have survived, because it was less abused, or something, or possibly all of the cards fell in the right spots, so it had all of its rated components able to sustain the higher voltage... the other one might have died, because of just a faulty capacitor or something, that was not happy with the, what should have been 'regular' voltage, becoming higher, and going above its ability to handle the voltage (possible manufacturing eror, or just a component at the lower end of the rated percentage of deviance)...

Personaly, thats just what I think it could be... it might be worth a read or something..
Being that it is an intel light, and its most likely a switch mode PSU for weight savings... it might just have barfed because fo what Ive previously stated...


Just some things to consider... 
If any of this helps, please, let me know! 
Also, if you think any of this is in error, please, also let me know.


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## ship (Mar 20, 2004)

Yes that seems very logical. Thanks for the expiation on how the x10 was working. Kind of had a feeling about that but it not effecting the power in a way I could meter I did not know it for sure. Makes perfect sense. Dooh, I did blow up a Mac 2K... Don't tell anyone, I fought quite the rear guard action making all around scratch their heads in confusion to get away with it. Ok they did not really believe me but I'm still useful around the shop in sweeping floors and getting Catalyst lamps cheap.

I guess I also should purchase the grounding type now given this instead of just reversing the thing around and running without ground on grounding equipment.

A double figure 8 for measuring 208v cold be interesting... difficult to make work short of taking the thing apart but still a very good assumption. I'm on the same page.

Time for some enterprising stage hand to make some up and make their million. Than again, a Gam Check style meter using amp/Volts meters would be very interesting to see on the market.


I'm the first to admit that while good at what I work with, there is still so much more I need to learn. Understood your phaze orientation, understand the principals even the taps off a transformer, but since I don't deal with it, it's not real to me yet - other than in this instance or our phaze harmonics issues at the shop. Anyway thanks for the help, very interesting and it's good to know there is people out there watching out for me also.


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## Mayhem (Mar 20, 2004)

This may be of some use:

http://www.allaboutcircuits.com/vol_2/chpt_10/3.html


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