Hi all-I'm relatively new to stage lighting and we've just started a community theater. Guess who's in charge of lighting. We have limited access to amperage - a total of 4 20a circuits. Yeah, I know, not much. We've been using 6 older 6" fresnels on a pipe above the 32' wide/24' deep stage and 8 Altman 6x9's on a downstage pipe 20' out and 20' up. Due to the aforementioned lack of juice, all are lamped with 500w. Most of our shows will be interior scenes that really just need general lighting. I've been looking at the threads on ETC adults vs jrs and am wondering what your thoughts are on moving up to one or the other and using the 375w lamps. Of course, money is a consideration. Thanks in advance from a novice!
Conventional Fixtures Small time theater
- Thread starterbigtim
- Start date
Rather than new instruments and HPL375 lamps (a $3000-4000 outlay), I'd first try 575W GLC lamps in your 6x9s and 575W BTH in your Fresnels.
Regular maintenance, particularly the cleaning of lenses and reflectors, will help in eeking out every possible lumen. See Lighting Fixture Maintenance.
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Well now that's somewhat debatable (see Is it acceptable to put 4x S4s on a dimmer?). But I would say that 4x575 is not significantly different than 4x500. At 120V, 19.2A vs. 16.7A, a difference of 2.5A.
Others' opinions?
Others' opinions?
Jackalope
Active Member
Theoretically there should be no problem.
If you are going to be the lighting guy unfortunately you are going to have to learn some basic electrical principles. One of those principles is the power law.
There are many ways to say this, but I think the easiest way is through a mnemonic known as the "West VirginiA" law or W=V*A. W is of course "watts", V=Volts, and A=amps. So to figure out the answer to your question lets do a little math...
First lets figure out how many watts (or power) that a 20a circuit can supply. I am assuming that your power is 120V (but if you live somewhere else it could be different say 240...You will need to know this as it is very important. If you live in the US chances are very high that you have 120v circuits)
W=20amps*120V therefore
W=2400 watts.
Now lets look at the 4 lamps at 575w which would total 2300 watts.
Since 2300 watts are less than 2400 watts of the circuit it looks like you should be okay. You can use this law for times when you have mixed lamp wattages and you want to know if you can safely load your circuits.
If you are going to be the lighting guy unfortunately you are going to have to learn some basic electrical principles. One of those principles is the power law.
There are many ways to say this, but I think the easiest way is through a mnemonic known as the "West VirginiA" law or W=V*A. W is of course "watts", V=Volts, and A=amps. So to figure out the answer to your question lets do a little math...
First lets figure out how many watts (or power) that a 20a circuit can supply. I am assuming that your power is 120V (but if you live somewhere else it could be different say 240...You will need to know this as it is very important. If you live in the US chances are very high that you have 120v circuits)
W=20amps*120V therefore
W=2400 watts.
Now lets look at the 4 lamps at 575w which would total 2300 watts.
Since 2300 watts are less than 2400 watts of the circuit it looks like you should be okay. You can use this law for times when you have mixed lamp wattages and you want to know if you can safely load your circuits.
STEVETERRY
Well-Known Member
All (4) circuits are coming out of the main panel. From there, power is being fed to 2400w dimmer packs with up to (4) 500 watt instruments per pack. I had neglected to mention that this is a 120v system. My limited understanding is that each 20a circuit is really rated at 80% capacity - or 16amps. Seems like 2300w (4x575w) might be pushing it?
STEVETERRY
Well-Known Member
Given that these breakers are standard thermal/magnetic 20A, you are only good to 1920W continuous (3 hours or more). Depending on the age of the breakers and the ambient temperature, loading them to 2300W will almost guarantee tripping problems. I suggest staying inside the 1920W limit.
Another solution would be to have an electrician do a load survey on the panel to see if there is any available power on the main feed. You do have four pole-spaces in the panel, and if the feeder has capacity, you could increase the breaker rating and cable size to your dimmers.
Note that this evaluation must be done by a qualified electrician.
If you can find the money, the 375W lamp in a Source 4 Junior will give you great efficiency.
ST
Okay, ignore my suggestion for the GLC in your 6x9s.
The following chart shows the performance of various lamps for the 360Q (first three) and S4/jr. (bottom three):
A little bit could be gained by using the EHC instead of the EHD in the existing fixtures. Interestingly, the performance of the HPL375/115 comes very close to matching that of the EHD. Of course I realize I'm only comparing the raw lamp data, and not taking into account the efficiency of the fixtures. Both the S4 and the jr. are far better at getting those lumens to the stage.
However, I stand by my suggestion on the BTH for the 6" Fresnels. 1) It is a better-performing lamp to the BTL, 2) 3x575=1725W, 3) ETC does not have a fixture equivalent to the Fresnel; the PARnel is not the same.
Mr. Terry's suggestion to hire a licensed electrician to gain more power is likely the best way to spend the money that you don't have. I don't see you gaining very much simply by buying 8x S4jr-36° and 6x Parnels all lamped at 375W. From a silly/practical point of view, you'd only have to stock one lamp type but would have to file two sizes of gel cuts.
The following chart shows the performance of various lamps for the 360Q (first three) and S4/jr. (bottom three):
A little bit could be gained by using the EHC instead of the EHD in the existing fixtures. Interestingly, the performance of the HPL375/115 comes very close to matching that of the EHD. Of course I realize I'm only comparing the raw lamp data, and not taking into account the efficiency of the fixtures. Both the S4 and the jr. are far better at getting those lumens to the stage.
However, I stand by my suggestion on the BTH for the 6" Fresnels. 1) It is a better-performing lamp to the BTL, 2) 3x575=1725W, 3) ETC does not have a fixture equivalent to the Fresnel; the PARnel is not the same.
Mr. Terry's suggestion to hire a licensed electrician to gain more power is likely the best way to spend the money that you don't have. I don't see you gaining very much simply by buying 8x S4jr-36° and 6x Parnels all lamped at 375W. From a silly/practical point of view, you'd only have to stock one lamp type but would have to file two sizes of gel cuts.
Two things come immediately to mind. The first is that, while it is inadvisable to run 2300W on a 2400W circuit unless it is specifically designed to do so, you can, very likely, run 2300W of lights at 80% on any 2400W circuit for a very long time.
Second, while you are quite limited in your power, you should think of this in terms of the maximum amount of power you can draw AT ANY ONE TIME. You can hang substantially more lights than you have power available if you take care not to put them all on full at the same time. While this may sound a little crazy at first, it means that you can create a number of different looks, with different instruments, allowing a lot more variety to your shows than you may initially believe (you could have a set of lights for a daytime look, an evening, indoor look and an outdoor look with a strong moon light, each using all of your available power (and, likely, mixing some of the instruments).
With all do respect to the big shows (they take their own level of capability), it takes much more thought, care and creativity to do a lot with a little than to do a show with everything you ever dreamed of having.
With regard to your S4 question, both the S4 and the jr are fine instruments. However, I cannot think of a situation that a S4 Jr. with satisfy that a full scale S4 will not. On the other hand, there are many tasks that a full size S4 with do that a Jr. will not. If you have the budget, I would strongly suggest the full size S4. Finally, I have a couple of S4 Jr zooms that I really like. However, I would advise against buying zooms for most theatres. If you pick up S4s on the used market, you can always buy different lens tubes to meet a specific need. As you have very limited hang points, I don't think you will need a very wide range of lenses.
Tim.
Second, while you are quite limited in your power, you should think of this in terms of the maximum amount of power you can draw AT ANY ONE TIME. You can hang substantially more lights than you have power available if you take care not to put them all on full at the same time. While this may sound a little crazy at first, it means that you can create a number of different looks, with different instruments, allowing a lot more variety to your shows than you may initially believe (you could have a set of lights for a daytime look, an evening, indoor look and an outdoor look with a strong moon light, each using all of your available power (and, likely, mixing some of the instruments).
With all do respect to the big shows (they take their own level of capability), it takes much more thought, care and creativity to do a lot with a little than to do a show with everything you ever dreamed of having.
With regard to your S4 question, both the S4 and the jr are fine instruments. However, I cannot think of a situation that a S4 Jr. with satisfy that a full scale S4 will not. On the other hand, there are many tasks that a full size S4 with do that a Jr. will not. If you have the budget, I would strongly suggest the full size S4. Finally, I have a couple of S4 Jr zooms that I really like. However, I would advise against buying zooms for most theatres. If you pick up S4s on the used market, you can always buy different lens tubes to meet a specific need. As you have very limited hang points, I don't think you will need a very wide range of lenses.
Tim.
I was in the same boat with a dinner theatre I used to be part owner in. I built a switching system to use three seperate sets of lights on the same set of dimmers. )That was back in the straight two scene boards with no DMX and no memory. You can have more dimmers than you have power for if you understand how much you can use at any given time. Say you have enough power to run 12 dimmers loaded, you could have 24 or even 36 dimmers with less on them and just figure which ones and how many you could use at any given time.
Osram a few months ago came out with the GLG / HP-375 and should have a long life version of it out soon. It has an improved more efficient filament over the GE and Ushio HX-400 for better optical performance and similar output to the HX-375w/C.
Assuming the above discussion about the output of the HPL 375, The 375w/115v GLG should be about as much output as the EHD at a much lower wattage and better color temperature. (Don't have the specifications on it yet.)
BTH for a Fresnel is nice in concept (Controlbooth came up with the idea for it) but on the other hand, it is designed to match up in output and color temperature to a 575w/115v GLC lamp. If the Lekos are only EHD, the Fresnels would not only eat up wattage but also out punch the Lekos and waste the output and color temperature by way of having to be dimmed. BTL lamps would be the best you could do unless you can go with some 200w/120v CVX/CVS lamps from Ushio or Wiko. Should work fine in the fixtures.
Assuming the above discussion about the output of the HPL 375, The 375w/115v GLG should be about as much output as the EHD at a much lower wattage and better color temperature. (Don't have the specifications on it yet.)
BTH for a Fresnel is nice in concept (Controlbooth came up with the idea for it) but on the other hand, it is designed to match up in output and color temperature to a 575w/115v GLC lamp. If the Lekos are only EHD, the Fresnels would not only eat up wattage but also out punch the Lekos and waste the output and color temperature by way of having to be dimmed. BTL lamps would be the best you could do unless you can go with some 200w/120v CVX/CVS lamps from Ushio or Wiko. Should work fine in the fixtures.
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