Conventional Fixtures Is this the right bulb?

ademhayyu1

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Mar 4, 2018
Location
Seattle, WA
Hello!

I'm putting together a list of lamps that we need to purchase for our HS Theater. For our LekoZoom 25-50deg, I would like to make sure that an EVR 120v500w bulb is right for the fixture. I want to make sure I have the right info before I pass it on.

I am also curious about something as well. When looking for the type of bulb needed for a light, should I focus on the voltage or wattage? I have info on the bulb type and wattage but not the voltage. Is it important on finding the exact voltage needed for that said fixture?

Thanks in advance!
 
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Les

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Feb 24, 2004
Location
DFW, Tx.
Is it a small screw-base type lamp? If so, EVR 99.9 of the time. Bi-pin will be EDH, GLA, etc (check fixture ratings). If in doubt, post a picture. I think I know the fixture you're referring to, but LekoZoom could refer to just about anything except a 360Q or Source Four.

Wattage vs voltage, etc... No, not really. Of course you need to make sure you aren't ordering 12v lamps or 230 volt lamps, but 115, 120, 130... It'll all work and is basically interchangeable (in that it won't damage fixtures or dimmers). You just might notice a difference in lifetime (130v is Long Life) but won't be as punchy as a 115 or 120v lamp. The "punch" comes at a cost of lamp life and the long life costs you in intensity. But basically, you only really need to stay within the rated wattage since that's what creates heat.
 
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Colin

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Jan 23, 2015
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Eastern Massachusetts
Also note there are other specs to be concerned with beyond volts and watts. Base type of course, and color temperature to match what you already have, and also LCL (light center length) which determines how the filament will align with the optics of the fixture. Wrong LCL can get you bad performance and elevated temperatures (can be a hazard, and can cause parts to fail sooner) because the lamp's output isn't properly reflected out the front of the fixture and turns into heat inside instead. So you can't just put in any lamp that fits in the base and expect correct performance. The foolproof way to tell what lamp you need is to look up the manufacturer's datasheet, which will commonly list several options of various wattages, long life vs high output...

And of course, let's call @ship for way more expert lamp info than you thought possible.
 

JD

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Jan 1, 2005
Location
North Wales PA
On voltage, remember that the post-dimmer lamp voltage is lower than your line voltage, even at 100%. Have someone measure your line voltage 4 or 5 times over the course of a week, at different times of day. If it's 118 to 121 then you are good with 115v lamps. 122 to 127, use 120v lamps. Over that, use 130 volt lamps. (Assuming your in the US 120v market.) As said before, there is not going to be a dramatic problem with any of the lamps. Using a lamp that is too high will give you a slight yellow look and great lamp life. Using one too low will give you a whiter color, but lifespan will suffer. Dimmers generally eat up about 3% of the line voltage. Very long cable runs can also chop a bit off the voltage. Improper dimmer alignment can also be a big factor. Some dimmers auto-regulate the voltage so that it never exceeds a specific voltage. If that is the case, and they are set for 115v, then those are the lamps to use.
 
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derekleffew

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(BTW) No, it is not the right bulb, but it may be the correct lamp. A bulb is planted in the ground to grow tulips and daffodils, or it may refer to the outer glass envelope of the lamp.

Also:
Socket. The base is part of the lamp.



-----
The foolproof way to tell what lamp you need is to look up the manufacturer's datasheet, which will commonly list several options of various wattages, long life vs high output...
Not as foolproof as one might think, particularly with older fixtures whereby lamp technology has advanced but the manufacturer hasn't bothered to update its spec sheets nor pay for a UL Listing using a current lamp. Classic example is the Altman 3.5Q ERS, where spec sheet says best lamp is EHD, but virtually everyone agrees GLC is not only fine, but a better replacement. Likewise, 360Q and EHG vs. GLE.

Unfortunately, there's no modern version, or even substitute, for the EVR lamp. Consider replacing the fixtures sooner rather than later.
 

Van

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ademhayyu1

Member
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Mar 4, 2018
Location
Seattle, WA
On voltage, remember that the post-dimmer lamp voltage is lower than your line voltage, even at 100%. Have someone measure your line voltage 4 or 5 times over the course of a week, at different times of day. If it's 118 to 121 then you are good with 115v lamps. 122 to 127, use 120v lamps. Over that, use 130 volt lamps. (Assuming your in the US 120v market.) As said before, there is not going to be a dramatic problem with any of the lamps. Using a lamp that is too high will give you a slight yellow look and great lamp life. Using one too low will give you a whiter color, but lifespan will suffer. Dimmers generally eat up about 3% of the line voltage. Very long cable runs can also chop a bit off the voltage. Improper dimmer alignment can also be a big factor. Some dimmers auto-regulate the voltage so that it never exceeds a specific voltage. If that is the case, and they are set for 115v, then those are the lamps to use.
Thank you for the info but I'm not really sure what you mean by "post-dimmer lamp voltage" and "line voltage". Sorry, I'm trying to learn more about electricity and voltage. Do you mind elaborating a bit on that part?
 

ademhayyu1

Member
Joined
Mar 4, 2018
Location
Seattle, WA
(BTW) No, it is not the right bulb, but it may be the correct lamp. A bulb is planted in the ground to grow tulips and daffodils, or it may refer to the outer glass envelope of the lamp.

Also:
Socket. The base is part of the lamp.



-----
Not as foolproof as one might think, particularly with older fixtures whereby lamp technology has advanced but the manufacturer hasn't bothered to update its spec sheets nor pay for a UL Listing using a current lamp. Classic example is the Altman 3.5Q ERS, where spec sheet says best lamp is EHD, but virtually everyone agrees GLC is not only fine, but a better replacement. Likewise, 360Q and EHG vs. GLE.

Unfortunately, there's no modern version, or even substitute, for the EVR lamp. Consider replacing the fixtures sooner rather than later.

While I was writing my post, I just wasn't sure whether it was "lamp" or "bulb". I've had people explain it to me so many times but it just keeps slipping my mind. Thanks for the catch!

I have tried to explain to the people in charge that we need to at least upgrade our older Ellipsoidals to Source 4's at the very least. But they keep hitting me with the good ol' "Does it work? Yes, okay so we're keeping it." Can't really argue with that fact nonetheless.
 

JD

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Jan 1, 2005
Location
North Wales PA
Thank you for the info but I'm not really sure what you mean by "post-dimmer lamp voltage" and "line voltage". Sorry, I'm trying to learn more about electricity and voltage. Do you mind elaborating a bit on that part?
If you would take a multimeter and measure an electrical outlet in the building, you would see the "line voltage." (basically) If you were to then use the multimeter to measure the voltage at one of your fixtures, set at 100%, it would be lower. This second voltage is a better indicator of what lamp voltage you should be using. The difference between the two is the voltage lost in the dimmer and wiring. (normal) It is predictably about 3 to 5% lower.
 

ademhayyu1

Member
Joined
Mar 4, 2018
Location
Seattle, WA
If you would take a multimeter and measure an electrical outlet in the building, you would see the "line voltage." (basically) If you were to then use the multimeter to measure the voltage at one of your fixtures, set at 100%, it would be lower. This second voltage is a better indicator of what lamp voltage you should be using. The difference between the two is the voltage lost in the dimmer and wiring. (normal) It is predictably about 3 to 5% lower.
Ahh, that makes a lot more sense. Thanks!
 

RonHebbard

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Location
Waterdown, ON, CA
Oh, don't mind the Curmudgeon! Technically, it is a lamp. Even the "light bulbs" you might have in your table lamp, are.. well... Lamps!
@ademhayyu1 and @JD and @derekleffew The bulbs providing illumination in your garden at night are light bulbs; the ones you plant in your garden are also bulbs but usually heavier. If you plant the heavier bulbs they often grow. If you plant the lighter bulbs you're usually wasting your time. If you're planting LED's you're in a whole new world of cutting edge agriculture and floral experimentation. @GreyWyvern Would you care to comment??
Toodleoo!
Ron Hebbard
 

BillConnerFASTC

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Joined
Jan 30, 2010
Location
Clayton NY 13624
If you would take a multimeter and measure an electrical outlet in the building, you would see the "line voltage." (basically) If you were to then use the multimeter to measure the voltage at one of your fixtures, set at 100%, it would be lower. This second voltage is a better indicator of what lamp voltage you should be using. The difference between the two is the voltage lost in the dimmer and wiring. (normal) It is predictably about 3 to 5% lower.
Well, in quite a few of my earlier projects, the dimmers were tapped up, meaning on their own teansformer and fed more volts than the basic convenience outlets fed from another transformer. This was to assure 120 volts to the lamp after the dimmer, before the now common 115 volt lamp. So it can get trickier. But I wouldnt worry too much. If you pick a long life lamp that fits youll be fine. I doubt you want the 200 or so hour lamp, more like 2000. Less light but you wont mind that nearly as much as the cost and bother of frequent replacements.

I never saw the fixture manufacturer and model number. We could be more help if we hew that.
 

JonCarter

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Apr 18, 2011
Location
Meridian, Idaho, US
Back in the 'good ol' days' in the 'big outdoor theeter' in Cleveland we had runs between 350' and 100' from the dimmers to the lighting positions. We used to order our 2kW leko, Fresnel & PC lamps from GE (their Nela Park lighting center was a mile away) with voltages from 100 to 120, depending on where we used them.

And an old LD worded under straightened me out the first time I called a "lamp" a "bulb." "LAMPS have three parts: a BASE, a FILAMENT and a BULB. Don't forget it." That's been 65 years ago and I haven't.
 

FMEng

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If the electrical engineer designing, or the electrician wiring a facility is doing a thorough job, they use larger than the minimum size wire to account for voltage drop on long runs. However, I rarely see that done anywhere. I know of one venue whose houselights are noticeably less bright in the areas farthest from the dimmer rack.
 

TimFrancis

Member
Joined
Mar 12, 2015
Location
Texas
Hello!

I'm putting together a list of lamps that we need to purchase for our HS Theater. For our LekoZoom 25-50deg, I would like to make sure that an EVR 120v500w bulb is right for the fixture. I want to make sure I have the right info before I pass it on.

I am also curious about something as well. When looking for the type of bulb needed for a light, should I focus on the voltage or wattage? I have info on the bulb type and wattage but not the voltage. Is it important on finding the exact voltage needed for that said fixture?

Thanks in advance!
If your Leko Zoom looks like the one pictured, an EHD 500W 120V Lamp, 2000hrs will work.
Link to a spec sheet with other lamp options - http://www.theatrecrafts.com/archive/documents/leko1830.pdf
strand2050sideps_large.jpg
 

BillConnerFASTC

Well-Known Member
Joined
Jan 30, 2010
Location
Clayton NY 13624
If the electrical engineer designing, or the electrician wiring a facility is doing a thorough job, they use larger than the minimum size wire to account for voltage drop on long runs. However, I rarely see that done anywhere. I know of one venue whose houselights are noticeably less bright in the areas farthest from the dimmer rack.
Wolftrap has (or had) no. 4s to 20 amp foh circuits. In incandescent days, I required no. 10s for all 20 amp and in a few places, no. 8s

Does not seem to be as critical in an LED world with loads of 500 to 1200 watts and tolerant power supplies. 2 - 1k incandescents much more intolerant of undervoltage in color and intensity.

I do not suggest relying on todays electrical engineers and electricians to consider this, at least not for stage lighting.
 
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