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Author Topic: Booth Electrical Loads Barry Floyd Phenomenal Film Handler Posts: 1079 From: Lebanon, Tennessee, USA Registered: Mar 2000 posted 01-03-2003 11:38 AM                        I've got to submit to our electrical engineer who is designing the "Power layout" for our drive-in, a table of "electrical loads" for our building, and had a question about the booth load requirements. I've got plenty of power available from the street, as 3 phase power is already run to the site at the edge of the road. My current lamphouse in storage is an 4kw ORC, but have considered replacing it with either a Strong or a Xenex II. I noticed when I removed my ORC from it's former booth that it had both 3 phase running to the power supply, and a 120v circuit run to the lamphouse controls... or something like that. I've got to tell my electrical engineer what size circuits to install and I don't have a clue. My projector is a Simplex XL with a RCA 9030 soundhead. I was figuring a 30amp 120v dedicated circuit would handle the projector, and another 20amp 120v dedicated circuit to cover the platter and MUT. Our theatre will end up being a twin screen by the beginning of 2004, but will open in May of 2003 with one screen. I'm having the engineer size the service entrance and panel board to accomodate both screens for ease of expansion in the future, but I need to tell him what to put in there now. Any help would be appreciated....  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 01-03-2003 12:22 PM                     I can't help you with your power ratings, but I can warn you that there are two kinds of three-phase power. There's three-phase where all three phases are stable voltage and there's three-phase where two are stable and the third is wild. One of these is called Delta, but I can't remember which. If you're going to use that third phase, make sure that the power company has the line transformered accordingly or you're sure to blow up a few things when the line fluctuates from 100v to 200v! Talk about eleventh hour excitement.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 01-03-2003 12:24 PM                        Provide your electrical engineer the electrical specifications of each piece of equipment you intend to have operating. Most should be in the "Manuals" section of Film-Tech. Good design will factor in additional load and additional circuits for later additions, as it's easier than ripping things out later to upgrade for unexpected additional circuits or load. Don't forget to have separate conditioned circuits for digital equipment (automation, sound system, computer). Emergency lighting and announcement capability is a good idea, even if not mandated by code in your area. And don't forget lightning protection.  |  IP: Logged Jon Bartow Master Film Handler Posts: 287 From: Massachusetts Registered: Nov 1999 posted 01-03-2003 12:56 PM                     Three phase delta is the kind you want. (all three legs are usable by single phase devices, as all three legs are stable) Not many places still have three phase wye but they are out there. If you have a three phase wye setup then you will find that every third slot for a breaker in your panel will be useless except for three phase devices. Is your projector motor three phase? or 220v? or 110v? It makes a big difference in the amp load required. Are you running a 70v amp for field speakers? if so big amps can be very power hungry. Try very hard (beg and plead if you have to) to have all of your sound equipment on the same phase and don't let them put any dimmers or big motors on that phase either (projector motor, HVAC, ice machine compressors, etc). It will save many potectial problems down the road. Also you want an isolated ground for the booth, not grounded through the conduit downstairs through the concession stand, but a good ground from the panel in the booth. 20 amps is usaully enough for a 110v or 220v projector, they are usually only 1/4-1/2hp motors. Make sure your electrician uses a breaker panel that is big enough to have several more circuits installed (if you are adding a screen later, than you will probably add another breaker panel, it simplifies things a bit. make sure your electricians plan for that too. Also, depending on the type of breaker panel, it can sometimes be a bit of a challenge to get replacement breakers. It would be a good idea to have a spare of each type/size used. They can even put the spare breakers in an unused slot in the panel. John is very wise to caution you about lightening protection. field speakers on poles are excellent lightening rods as is a building alone in the middle of a field. Make sure the field speaker lines are well protected. As has been said, provide your elec. eng. with all of the equipment specs and s/he will be able to plan accordingly. My guess is that a 500-600amp three-phase (delta) will more than suffice for your current (pun very intended ) and future needs. Jonathan  |  IP: Logged Ian Price Phenomenal Film Handler Posts: 1714 From: Denver, CO Registered: Jun 99 posted 01-03-2003 01:05 PM                     I don’t know about a Drive-In but this is what I understand that each auditorium needs in an indoor multiplex. Ask for Switchable Circuit Breakers as you may be turning these off each night. 3 Phase 30amp circuit for the Lamphouse 120v 20amp Exhaust Fan 120v 20amp Projector 120v 20amp Automation 120v 20amp Platter 120v 20amp Make-Up Area (Only one needed per complex) 120v 20amp Accessory Plugs in Booth 120v 20amp Sound Processor 120v 20amp for each 2 Amplifiers 120v 20amp for each House Dimmer 120v 20amp Isle Lights 120v 20amp Auditorium Plugs for vacuums, blowers and such (Leave on 24 Hours) 120v 20amp Emergency Lights & Exit Signs (Leave on 24 Hours) 120v 20amp Clean-Up Lights (Leave in 24 Hours) The load on each circuit will be low, but this is a great way to isolate each circuit for service and diagnosis. This can probably be served with a 200amp panel.  |  IP: Logged Barry Floyd Phenomenal Film Handler Posts: 1079 From: Lebanon, Tennessee, USA Registered: Mar 2000 posted 01-03-2003 03:48 PM                        Ian, you never cease to amaze me the long lists of categories you can come up with, and all very accurate. On a side note to this topic, I took the list of "operating expenses" you listed in the "Business Plan" topic a year or so ago, and incorporated them into our cash flow plan for the drive-in. I had my loan approved for the purchase and construction of the drive-in in less than a week. My banker said, "For someone who's never been in this business before, you sure have your expense categories very well detailed." John and Jon had mentioned "lightning protection" for the booth, I'm assuming for stray random strikes in the field running in on the field speakers. We will not have any field speakers... now days they're just too costly to maintain, and also expensive to install. I've got an FM stereo transmitter that runs at a 1/2 watt that won't broadcast the signal much further than the property boundaries.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 01-03-2003 04:00 PM                        Your projection room / concession area sitting in the middle of an open field is a nice target for lightning. Protect those buildings, and also protect against the damage a lighting hit will have if it gets into your power lines (e.g., if you have field lights at the top of your screen, they are likely to get hit, with the surge knocking out some of your equipment). My home has lightning rods, and a surge protector where the power line enters the house. My phone, cable, and antenna lines all have "lightning arresters", with a solid path to an outside ground. Four houses in our hilltop neighborhood have been hit, with varying levels of damage. I've lived through enough lightning storms sitting in a drive-in booth to appreciate the need for lightning protection.  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 01-03-2003 04:08 PM                     I can't remember the last indoor theater project I've been involved with that didn't have lightning rods around the perimeter of the roofline and on each RTU and exhaust fan.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 01-03-2003 04:11 PM                        Barry, you might up that figure for the lamphouse(s) a bit. Our older X-60 supplies were rated for 50 amp circuits. You could probably downgrade that a bit if you put in switchers... but the extra capacity won't hurt.  |  IP: Logged Mike Fitzgerald Expert Film Handler Posts: 224 From: Castle Hayne, NC, USA Registered: Jun 2002 posted 01-03-2003 04:12 PM                     Thanks for the information. I was looking for the very same information for my portable booth. The only difference is that I am going to be using a 3 phase generator with carbon arcs lamps. I think the lamphouse alone will use 50 amps 3 phase just by themselves and about another 8=20 amp circuits for the rest of the booth.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 01-03-2003 05:03 PM                     Supply your engineer with electrical demands of each and every component you intend to use. And be advised....if any of this equipment does not have a UL certification, the electrical inspector will probably not sign it off and allow operation. If any of your equipment does not have the UL sticker physically affixed to the equipment, be prepared to spend alot of time finding out the UL info the contractor/inspector wants.  |  IP: Logged Bruce Hansen Jedi Master Film Handler Posts: 847 From: Stone Mountain, GA, USA Registered: Dec 1999 posted 01-03-2003 05:11 PM                     OK, it's been a long time since I studied this stuff, but isn't 220 Delta the system that does not have a common neutral, and therefore is only good for 3 phase 220 devices? And I believe that one leg is a little higher than the others, but does not vary. "Y" has a common neutral (the center point of the "Y"), and can be used for 115 volt devices.  |  IP: Logged Ron Lacheur Jedi Master Film Handler Posts: 650 From: British Columbia, Canada Registered: Feb 2002 posted 01-03-2003 05:21 PM                     from: http://www.franceformer.com/foreign_current/home.htm Delta systems: In its basic form the delta system utilizes a 3-wire scheme -- 3 line (or "hot") wires. One phase (that is, line-to-line) may be center-tapped, with the centertap becoming a neutral conductor. On such center-tapped systems the higher voltage is derived from a line-to-line connection while the lower voltage is derived from a line-to-neutral connection. So, the indicated higher voltage in the tables may be either 3-phase or single phase; however, the indicated lower voltage is always single phase. Delta systems may be recognized in the tables by the ratio of the line-to-line to line-to-derived-neutral voltage, i.e.the higher voltage is twice the lower voltage.  |  IP: Logged Gordon Bachlund Jedi Master Film Handler Posts: 696 From: Monrovia, CA, USA Registered: Aug 1999 posted 01-03-2003 05:40 PM                        Today the most common three-phase electrical services are “wye” connected, usually 120/208V and 277/480V in the US. Thus, electrical panels will have three “hot” buses (phases A, B and C) and a neutral bus, plus a separate ground bus. Any phase to neutral connection will afford the lower voltage (120V or 277V), while any phase to phase connection will afford the higher voltage (208V or 480V single phase), and while any connection to all three phases will afford actual three-phase power (208V or 480V 3-phase). Some utilities still employ an older scheme that was derived from a delta connection of three single-phase transformers, one larger than the other two, to afford both 120/240V single phase (from the larger transformer which has a center tap for the neutral), or 240V three-phase from all three. This enabled a single bank of pole-mounted transformers to serve a building’s lighting load at 120/240V through one meter, and a building’s three-phase “power” load through another meter. Usually the rate was a bit lower for the “power” load. I have seen this in countless neighborhood theatres in the Los Angeles area in the 50s and 60s. One house in which I worked was served 125VDC by the local utility, and the DC service was used for the projection lamps. When I asked why the utility was still selling DC, I was told that some older downtown office buildings had DC services for their elevators, obviously pre-dating the more modern Ward-Leonard style motor-generator drives. Barry, those who have advised that you provide the electrical engineer with a complete list of known (and future) loads are correct. He will especially appreciate seeing copies of specifications and manuals. He will then perform such calculations as will ensure that your installation is proper and safe, to say nothing of meeting code. And, yes, most inspectors will look for UL labels, dedicated “green” grounding conductors, transient voltage surge suppressors, proper lightning protection where required, and other safety related practices.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-03-2003 08:57 PM                     Be wary of supplying a list like the Ian mentioned...whilst you will want "circuits" like that...that isn't your load persay. The actual draw on a typical single-projector multiplex type load panel is typically from 40-50amps 3-phase. That is...with your show running and if you were to measure the feeder lines with a ammeter that is about all you would be using. Obviously, your lamp size, number of amplifiers and various lighting circuits can affect this. A circuit breaker that is 20 amps protects the wire connected to it. Just because you have some 30 20-amp circuits in the panel doesn't mean you need a 200-amp panel and service. Your Electrical Engineer (with his/her PE) will want to know what your actual load will be and how many branch circuits (you don't want to get a small panel and then run short of circuits). You then will want to provide your best estimate of the actual load on each circuit (projector motor, dimmers...etc)...that way they can balance out the panel so that each leg will have a similar load. A motor may draw 20 amps or so to turn on but run on less than 5-amps. So for most of the time, 5-amps is the load on that circuit (phase) but you will want a 20-amp circuit to handle the turn on surge. If you spec willy-nilly all these 20-amp circuits (as if they are all 20-amps all the time) you will be paying for that much service whether you use it or not in some areas. If it is a renovation you may have to pay for a "heavy-up) if it is new, you may be given 277/480 lines and will have to pay for the step-down transformers...the larger the KVA (kilovolt-amps) the more you pay. Steve  |  IP: Logged

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