Electric Question

Sly9

Sly9

Active member
I've recently picked up some used Arri 1K Fresnels. Here in Spain I have some 2000W step-up/down transformers. I'm trying to figure out if I can safely hook-up one light (1x 1K) to a single transformer? Could anyone chime in? If more information is needed, I'll do my best to provide it. Just wasn't sure and again, didn't want to fry a light, transformer, etc. TIA for any time and help!

BTW >>> The 1K Fresnels are 120v (US) powered which is why I need the transformer.
 
I'm in Spain atm, as it says in my OP. David said "your country". Spain is not my country. This is also reflected in my handle info on the side. I'll be going back to US soon so the ignoring of my question and saying to just change everything over to EU standards did not answer the question. The answer is yes, I can run a 1K Arri Fresnel on a 2000w step-up/down transformer.

Edit: Also, for anyone out there or in the future that may need this, here is some extra info that was provided via another source:

"The heads are really voltage-independent. They only care if the amperage exceeds the rating of the wiring. A 1000w 220v lamp pulls half as much amperage as a 1000w 110v. So it is fine. The light-head does not care."

...and...

"Cycles don’t matter in a tungsten light. They don’t flicker at all like an HMI."

So, regardless if a country is 50 or 60 cycles, you should be able to plug it directly into the wall (with adapter), assuming you are using the correct bulbs for the voltage (i.e. 120v bulb to 120v power, 220v bulb to 220v power).
 
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You gotta admit, this post seems like it was written in a purposefully confusing manner and your replies cagey.
 
Transformer will work fine as long as the total wattage load is below its maximum rating and max voltage is below the wire insulation rating, which is typically 600V. 2/3rds rating gives a good safety margin. 1k is 50%.

Boost/buck passive transformers don’t care what line frequency they see as long as it is AC.
 
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Run&Gun said:
You gotta admit, this post seems like it was written in a purposefully confusing manner and your replies cagey.
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The only "purpose" I had, was to answer my question. If it wasn't written in a way you could understand, you could ask for a re-wording instead of trying to project onto me. Additionally, I'm guessing you "purposefully" used cagey incorrectly, as it means reluctant to give out info owing to caution or suspicion. See my OP: " If more information is needed, I'll do my best to provide it." You asked a question and I gave you a response with info. That seems to be inconsistent with the definition, and I have no suspicions of David, as his posts are almost always helpful, and on point.

No where in David's response did he talk about whether it was ok or not to use the transformers to power the light(s). He's well within his rights to voice his opinion and he advocated for things to be changed to Spain's standards. However, this did not answer the question I originally posted. None of your responses have helped thus far to answer the original question or provide further insight into said question. Should I assume you are going continue on in a similar manner of providing us with your mischaracterizations of my replies, or can we can keep this educational and about the original question?
 
So in one country you have 230 and in another you have 110, and you are flying your Fresnels in and out of each country? Surely in the country where the fixtures are you put in lamps that are of the right voltage. Even if you are crazily flying in and out with the two Fresnels, you just have a correct lamp at both ends and swap them. Transformers for more than 5A are pretty heavy and massive things, so a real inconvenience. The only sensible answer is the right lamp in the right country. Using a transformer when you could swap the lamp is just a bit odd!

No idea why you got hot under the collar - I read your post and thought exactly the same thing.
 
Razz16mm said:
Transformer will work fine as long as the total wattage load is below its maximum rating and max voltage is below the wire insulation rating, which is typically 600V. 2/3rds rating gives a good safety margin. 1k is 50%.

Boost/buck passive transformers don’t care what line frequency they see as long as it is AC.
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Razz, ah ok. Thanks for the response/info! One of the things I was unsure of was what the total draw was from the light itself since I haven't got the units in hand yet. I've been going off an Arri spec sheet and it lists the bulb as 1000w and dimmer as 1800w, but I was unsure if that was the max draw or if there were additional components in the system which needed power as well.

WRT your info about the wire insulation rating, does that mean that 600v wire is standard around the world for these smaller (read: household, lower wattage) situations? For the safety margin, you mentioned 2/3rds rating...does that mean 2/3rds of total rated wattage from the transformer (source)? In my case, if I have a 2000w transformer, that means the draw shouldn't be above 1,333w correct? Apologies for my ignorance, I'm not great when it comes to electrical matters.
 
paulears said:
So in one country you have 230 and in another you have 110, and you are flying your Fresnels in and out of each country? Surely in the country where the fixtures are you put in lamps that are of the right voltage. Even if you are crazily flying in and out with the two Fresnels, you just have a correct lamp at both ends and swap them. Transformers for more than 5A are pretty heavy and massive things, so a real inconvenience. The only sensible answer is the right lamp in the right country. Using a transformer when you could swap the lamp is just a bit odd!
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I have transformers on hand, as stated in my original post. All I'm looking to know is whether or not I can safely use a single 1K Fresnel that is US wired/plugged/bulbed, on said transformer. It appears that the answer is "yes, I can safely do that". After I leave Spain, I'll likely not be coming back, so I'm not "crazily" flying in and out with them. Since I already had a possible solution with the transformers I own, I thought it made more sense to save money and use what I have already, instead of spending money, time, and resources to change them over to Spain plugs/bulbs, just to convert the plugs back to what they originally were, when I return home. I've already got the US bulbs, so there would be no additional cost unless the moving company breaks them.

You are right about the transformers being heavy things...I can still pick up the ones I have with one hand though, and it appears that I can safely use them based on the responses from other electrics.

But I don't have the lamps to swap for the voltage here, and as I copypastad here in an earlier post, you can just use a wall adaptor if you did have the bulb, and not have to worry about the cycles. I have the US to Spain wall adapters but don't have the 220v bulbs. Also, the bulbs for 220v are 2x-3x more expensive than the 110v bulbs.

paulears said:
No idea why you got hot under the collar - I read your post and thought exactly the same thing.
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No idea why R&G mischaracterized my intentions when I was clear about them from the get-go. Guess I don't post how you all want. No need for the drama as it adds nothing to the question.
 
You've misunderstood the specs. The Arri 1K draws less than 5A on 230V mains power (the rough and nearly correct formula is A x V =W). The dimmer figure is the lowest wattage suitable, due to the cold filament start up surge, so as professional dimmers usually come in 2K versions, with a few 1K versions, if you are buying a dimmer (and I'm not certain you should), then it needs to be rated more than the lamps usual rating. In Europe/UK, the power supply cable to an Arri 1K would be quite happy if it was 1.5mm2, we don't use wire gauge here. The alternative is of course 2.5mm2 - which is much heavier and a bit pointless for a 1K lamp. The transformer needs to be rated for the cold start surge, so a 2K capable transformer would be fine. For europe the usual spec for flexible cable is H05 or H07 rubber. BS/EN 50525 specs cover up to 750V, so suitable for our usual single phase supply, but also in 5 core versions, for 3 phase with it's higher phase to phase voltage.

The rough and ready Amps times Volts equals Watts formula is the one we all use for calculations. I've got some transformers and the damn things are too heavy and cumbersome to carry around unless you really have to. If you are thinking about doing this properly, then you should also be using 16A Blue connectors - but they are bigger than the usual domestic types, so just stick in EU/UK lamps when you're in Europe or the UK. I cannot speak for the US. Their rules are country specific.
 
paulears said:
You've misunderstood the specs. The Arri 1K draws less than 5A on 230V mains power (the rough and nearly correct formula is A x V =W). The dimmer figure is the lowest wattage suitable, due to the cold filament start up surge, so as professional dimmers usually come in 2K versions, with a few 1K versions, if you are buying a dimmer (and I'm not certain you should), then it needs to be rated more than the lamps usual rating. In Europe/UK, the power supply cable to an Arri 1K would be quite happy if it was 1.5mm2, we don't use wire gauge here. The alternative is of course 2.5mm2 - which is much heavier and a bit pointless for a 1K lamp. The transformer needs to be rated for the cold start surge, so a 2K capable transformer would be fine. For europe the usual spec for flexible cable is H05 or H07 rubber. BS/EN 50525 specs cover up to 750V, so suitable for our usual single phase supply, but also in 5 core versions, for 3 phase with it's higher phase to phase voltage.
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Thanks for pointing out where I had made the mistake. I'm still trying to wrap my head around this electrical stuff so I really appreciate the extra info you provided here! Question...how much more does the dimmer need to be rated for in order to handle the lamp (in this case, the Arri 1K Fresnel)? Do you have a formula you typically use for the dimmer? Also, how do you calculate the cold start surge, or is that synonymous with the bulb's voltage (i.e. 110v surge for a 110v bulb/unit)?

paulears said:
The rough and ready Amps times Volts equals Watts formula is the one we all use for calculations. I've got some transformers and the damn things are too heavy and cumbersome to carry around unless you really have to. If you are thinking about doing this properly, then you should also be using 16A Blue connectors - but they are bigger than the usual domestic types, so just stick in EU/UK lamps when you're in Europe or the UK. I cannot speak for the US. Their rules are country specific.
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I'm not sure what connectors the seller put on, but I'll be sure to check them upon arrival and I'll test to see if they fit in the wall adaptors I have. At this point, it looks like I should invest in another set of bulbs for my time left here, as you are right that it will get tiresome to lug around the transformers. Again, thanks for the info! Cheers
 
The seller replied that he put on "15amp Edison’s" connectors. That is not quite the 16A connectors you mentioned. Do you think there will be an issue? The seller also said that the lights pull about 8.3amps, but I'm guessing that is based on a 110v system, correct? That would be less in 230v system. A x 230v = 2000w, amps = 8.3, is that correct? Then for a 110v system, wouldn't that be 18.2 amps?

Edit: It looks like I used the wrong numbers again. I think the correct numbers should be with 1000w (from the light) instead of the 2000w (from the transformer).

So in a 110 system, it would be just a little over 9a (1000w = 9.1a x 110v (seller used 120v)). Then in a 230v system... 1000w = 4.3a x 230v.
 
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