I think he means the response of the cap, not the general electron flow. Some people claim smaller caps respond quicker to dynamics...
I agree the cost of such a system just doesnt make up for it. Tho for the sake of going beyond, go for it...
Actually, speaker arrays are getting more and more efficient. Considering the output capabilities of your average amp rack for those systems, they don't really waste that much energy at idle. Things get even better if those arrays are self powered and the amp modules have been designed for the cabinet they are in. Also, unless you are hosting DJ Tiesto or the like the average power consumed isn't that high.
Lighting is getting better too. Very few if any large acts are using hundreds of 1k par cans anymore. That's a bit 1980's to most. LED fixtures, LED video walls, more efficient ballasts for the HID lamps in intelligent fixtures and large video projectors, and the use of video driven LED based fixtures as part of the lighting design have notably cut down on power consumption.
Lighting is getting better too. Very few if any large acts are using hundreds of 1k par cans anymore. That's a bit 1980's to most. LED fixtures, LED video walls, more efficient ballasts for the HID lamps in intelligent fixtures and large video projectors, and the use of video driven LED based fixtures as part of the lighting design have notably cut down on power consumption.
zigzagflux
the motor ran a hollow drum at 5000RPM. The outside of the drum was a negative with 132 rows of characters on the negative. Inside the drum was a bank of strobe lamps. When the right character was in front of the right strobe lamp the lamp would flash and project an image of the character to a print drum and voila! electronic printing. Long before laser printing. Oh yeah, only one character set, only landscape, only single sided, only 20lb paper, only 8 1/2 by 11inch paper and no graphics.
the motor ran a hollow drum at 5000RPM. The outside of the drum was a negative with 132 rows of characters on the negative. Inside the drum was a bank of strobe lamps. When the right character was in front of the right strobe lamp the lamp would flash and project an image of the character to a print drum and voila! electronic printing. Long before laser printing. Oh yeah, only one character set, only landscape, only single sided, only 20lb paper, only 8 1/2 by 11inch paper and no graphics.
The subtle point with modern lighting is that while something like the "Bomber rig" switched banks of lanterns so only part of that massive number of parcans was on at any one time, the modern discharge stuff is struck at the start and runs continuously right through.
Lighting is still the power consumption king.
Now 208 or 220 split phase possibly makes sense in the US because of the massive weight savings, less current means less voltage drop and the higher voltage means that a given voltage drop matters less to start with, but I don't see genuine three phase input amps ever really being a mass market product.
Regards, Dan.
Lighting is still the power consumption king.
Now 208 or 220 split phase possibly makes sense in the US because of the massive weight savings, less current means less voltage drop and the higher voltage means that a given voltage drop matters less to start with, but I don't see genuine three phase input amps ever really being a mass market product.
Regards, Dan.
Interesting question.. It's actually strange that 3 phase powered amplifiers are not available especially for very high power touring and installed audio. AvIability of power source does not seem to be the issue. Installations would have back up generators and feeder lines that are essentially 3 phase. Tour sound that cater to more than 500 people would normally have about 10,000 watts Rms sound and the stage lighting & peripheral lighting that runs over 20 kw typically. The power for a touring installation is usual a portable generator placed far away from the stage, to minimize generator sound.
Most professional high power amplifiers like QSC, CROWN etc use Switched mode powersupplies. The QSC PL-380 rated for 8 KW bridge mode, has DC rail voltage of +/- 180 volts !!!. The SMPS uses a half bridge topolohy with a ferrite transformer. A 220 Volt mains supply rectified and filered gives a no load of 310 volts DC. The power devices for this is rated for 600 volts PIV. ( PL-380 uses ultrafast IGBT. )
Now if 3 phase 380 volt Mains power were to be used, the DC voltage would be 538 volts. Here the power devices are to rated for 1200 volts PIV. IGBT rated for 1200volts are fairly common nowadays. The rest of the SMPS design follows the 220 volt design.
The pro's for a 3 phase powered amplifiers are.
1. There are 6 half waves in one mains cycle in a 3 phase rectified circuit, the single phase would have only 2. The advantage is that the ripple content in 3 phase rectified DC is very less (around 4%) compared to single phase rectified DC (around 46 %).
2. The outcome is much less capacitance required in the DC filter for the same ripple content in the rectified out put.
3. Hence Lower cost and more importantly, significantly lower in rush current on power on.
4. At the mains power distribution level, 3 phase would load all 3 phases equally hense avoid phase imbalance in the mains supply.
5. When powered by generators, operators generally increase the generator capacity to account for phase imbalance. In 3 phase powersupplies one could reduce over capacity and thus reduce capital and running costs. (Higher rated generators consume more fuel even during idle running)
6. In areas where Delta / Y mains power is used, phase imbalance causes variations in mains voltages, these sometimes overstresses the power components that lead to break down. 3 phase powered equipment in inherently stable.
The only contra I can think if is that due to higher voltage levels, safety is a key issue. The insulation levels need to be higher and also the safety levels. This being a design, manufacture and service level consideration, the user is not concerned by it.
Most professional high power amplifiers like QSC, CROWN etc use Switched mode powersupplies. The QSC PL-380 rated for 8 KW bridge mode, has DC rail voltage of +/- 180 volts !!!. The SMPS uses a half bridge topolohy with a ferrite transformer. A 220 Volt mains supply rectified and filered gives a no load of 310 volts DC. The power devices for this is rated for 600 volts PIV. ( PL-380 uses ultrafast IGBT. )
Now if 3 phase 380 volt Mains power were to be used, the DC voltage would be 538 volts. Here the power devices are to rated for 1200 volts PIV. IGBT rated for 1200volts are fairly common nowadays. The rest of the SMPS design follows the 220 volt design.
The pro's for a 3 phase powered amplifiers are.
1. There are 6 half waves in one mains cycle in a 3 phase rectified circuit, the single phase would have only 2. The advantage is that the ripple content in 3 phase rectified DC is very less (around 4%) compared to single phase rectified DC (around 46 %).
2. The outcome is much less capacitance required in the DC filter for the same ripple content in the rectified out put.
3. Hence Lower cost and more importantly, significantly lower in rush current on power on.
4. At the mains power distribution level, 3 phase would load all 3 phases equally hense avoid phase imbalance in the mains supply.
5. When powered by generators, operators generally increase the generator capacity to account for phase imbalance. In 3 phase powersupplies one could reduce over capacity and thus reduce capital and running costs. (Higher rated generators consume more fuel even during idle running)
6. In areas where Delta / Y mains power is used, phase imbalance causes variations in mains voltages, these sometimes overstresses the power components that lead to break down. 3 phase powered equipment in inherently stable.
The only contra I can think if is that due to higher voltage levels, safety is a key issue. The insulation levels need to be higher and also the safety levels. This being a design, manufacture and service level consideration, the user is not concerned by it.
3-phase is for large motors. And long feeder lines. The 10 miles from here to the old hydro-dam. Note even the last mile down my street.
The short run from the site transformer bank to the audio rack does not justify complication for a 4-hour show. Bring 1 2 or 3 phases as convenient and plug-in your multiple 1-phase loads. (Note that lamps are all 2-wire thus single-phase.) (No 3-phase speakers either.)
Phase imbalance is totally someone else's problem.
High voltage in cheezy boxes like typical audio amplifiers is reckless. Even in heavy cast-iron motors in hazardous factories we tend to stay below 600V.
The short run from the site transformer bank to the audio rack does not justify complication for a 4-hour show. Bring 1 2 or 3 phases as convenient and plug-in your multiple 1-phase loads. (Note that lamps are all 2-wire thus single-phase.) (No 3-phase speakers either.)
Phase imbalance is totally someone else's problem.
High voltage in cheezy boxes like typical audio amplifiers is reckless. Even in heavy cast-iron motors in hazardous factories we tend to stay below 600V.
Some guy from Australia had the same axe to grind here a few months back.
Same smart guy theories, not backed by actual experience.
Issue with voltage ratings on the secondary sides too.
Decided too complex, IIRC.
Read it up.
How many concert stages will give you even 3 phase power?
As in all voltages same (here 20 volt variation is common).
And after the show, a lot of people are tired, and / or high.
Asking for trouble if they are careless while dismantling the equipment.
10 kW is a light industrial load, may be big for a concert.
Not in real life.
Same smart guy theories, not backed by actual experience.
Issue with voltage ratings on the secondary sides too.
Decided too complex, IIRC.
Read it up.
How many concert stages will give you even 3 phase power?
As in all voltages same (here 20 volt variation is common).
And after the show, a lot of people are tired, and / or high.
Asking for trouble if they are careless while dismantling the equipment.
10 kW is a light industrial load, may be big for a concert.
Not in real life.
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Most U.S. performance venues have three phase power. Virtually all of the hoist motors require three phase power.
However three phase audio amplifiers would require in effect three power supplies that run off of each phase and combine the DC output. Before modern switching supplies the cost and final weight of the transformers would have been ridiculous.
Modern amplifiers with switching power supplies could add two more switchers to run off three phase. Of course competent engineering would design the unit so that each switching supply could handle the entire load. Otherwise a method would be to reduce the power rating when there was an AC supply issue.
Of course folks who use large sound systems have multiple amplifiers. The efficient way to use the available AC power in the U.S. is to set the amplifiers to run on 220-240 volts and wire three amplifiers as a three phase load. Done that way you can also run them as single phase and balance the load by using two triples split across the single phase source.
If just playing dives then the amplifiers would be set for 120 volts. Of course most pro power amplifiers with switching power supplies can run from 120 or 240 volts. However if the AC lines are significantly off the standard voltages some switching power supplies at full load will fail. The design is optimized for correct supply voltages and the active device switching times will not be optimized for off voltages.
However three phase audio amplifiers would require in effect three power supplies that run off of each phase and combine the DC output. Before modern switching supplies the cost and final weight of the transformers would have been ridiculous.
Modern amplifiers with switching power supplies could add two more switchers to run off three phase. Of course competent engineering would design the unit so that each switching supply could handle the entire load. Otherwise a method would be to reduce the power rating when there was an AC supply issue.
Of course folks who use large sound systems have multiple amplifiers. The efficient way to use the available AC power in the U.S. is to set the amplifiers to run on 220-240 volts and wire three amplifiers as a three phase load. Done that way you can also run them as single phase and balance the load by using two triples split across the single phase source.
If just playing dives then the amplifiers would be set for 120 volts. Of course most pro power amplifiers with switching power supplies can run from 120 or 240 volts. However if the AC lines are significantly off the standard voltages some switching power supplies at full load will fail. The design is optimized for correct supply voltages and the active device switching times will not be optimized for off voltages.
Because it's stupid to put all your eggs in one basket. Does anyone make 10KW speakers? No. They may put an array into one box but even that has to be small enough to be installed at height. And professional speakers are 10dB more efficient than domestic products so you only need 10% of the power that you might think. When you have an array of amps, each with its own speaker, you can have failures and the show goes on. An amp that can only be used with 3-phase power has a tiny market and will be expensive and a maintenance headache. And dangerous because 10KW requires class 1 wiring. Just a bad idea. If you are interested in huge amps, yes, they are used for shake tables and they run on 3-phase 480V. You may want to look up arc-flash accidents/death on youtube.
Quite a stir 
.
A few things need to be straighened out.
1. I dont mean use a 10 Kw single amp. The QSC PL380 is rated for 8KW, it is used in arrays. A close look at the specs will show a current consumption of 11 amps at 220 volts (18 A @ 110V ) which means the true RMS power can not theoretically exceed 2.4KW. In India the maximum single phase current that can be drawn from the mains should not exceed 12.5 amps. Hence this spec is with in limits. Incidently this is about the same power consumption of a 1.2 ton Air conditioner. Once you line up more than one amp, the practice is to power it in another phase. Equal load on a 3 phase mains would need amps connected in three's. This is also not ideal since all amps will not have the same power consumption unless all are set to the same volume and program content. Thus a 3 phase input amplifier would load all phases equally without imbalance.
2. As far as power supply topography goes, you dont need 3 transformers in a SMPS. The 3 phase mains is converted directly to a high voltage DC bus with a 3 phase rectifier (6 diodes). The dc bus powers a regular 'H' bridge inverter that runs at a high frequency. The H bridge powers the primary of a single phase ferrite transformer. A centertapped secondary will step down the voltage to use able levels, the high frequency ac voltage is rectified by fast recovery diodes. I have included a simple schematic.
3. A three phase smps amp is not intended for home / club use. This more for installed sound like arena's, outdoor shows etc. These places will invariable have 3 phase supply. Outdoor shows are normally powered by portable generators that are essentially 3 phase. I am only considering 220 volt or 415 volt 3 phase mains, known in my part of the world as "Low Tension", the usual voltage levels for homes and small industry. For huge motors like the old hydro dam uses "High Tension" typically 6600 volts / 11KV. HT is used to power motors and other loads that are about half a Megawatt upwards. Such power, I recall was used for Michael Jacksons India tour and Pink floyd's Pulse.
.A few things need to be straighened out.
1. I dont mean use a 10 Kw single amp. The QSC PL380 is rated for 8KW, it is used in arrays. A close look at the specs will show a current consumption of 11 amps at 220 volts (18 A @ 110V ) which means the true RMS power can not theoretically exceed 2.4KW. In India the maximum single phase current that can be drawn from the mains should not exceed 12.5 amps. Hence this spec is with in limits. Incidently this is about the same power consumption of a 1.2 ton Air conditioner. Once you line up more than one amp, the practice is to power it in another phase. Equal load on a 3 phase mains would need amps connected in three's. This is also not ideal since all amps will not have the same power consumption unless all are set to the same volume and program content. Thus a 3 phase input amplifier would load all phases equally without imbalance.
2. As far as power supply topography goes, you dont need 3 transformers in a SMPS. The 3 phase mains is converted directly to a high voltage DC bus with a 3 phase rectifier (6 diodes). The dc bus powers a regular 'H' bridge inverter that runs at a high frequency. The H bridge powers the primary of a single phase ferrite transformer. A centertapped secondary will step down the voltage to use able levels, the high frequency ac voltage is rectified by fast recovery diodes. I have included a simple schematic.
3. A three phase smps amp is not intended for home / club use. This more for installed sound like arena's, outdoor shows etc. These places will invariable have 3 phase supply. Outdoor shows are normally powered by portable generators that are essentially 3 phase. I am only considering 220 volt or 415 volt 3 phase mains, known in my part of the world as "Low Tension", the usual voltage levels for homes and small industry. For huge motors like the old hydro dam uses "High Tension" typically 6600 volts / 11KV. HT is used to power motors and other loads that are about half a Megawatt upwards. Such power, I recall was used for Michael Jacksons India tour and Pink floyd's Pulse.
3 phase PFC power supplies are much more complex than a single phase PFC power supply. If you use amplifiers in groups of 3 then you have negated the balanced phase loading advantage of the complex 3 phase supply. Small venues typicaly have 32A 1P here (UK) but often upto 125A 3P is available, festivals ask what you want and have generators and distros everywhere (probobly upto 400A/600A powerlock but I have never need this much for audio).
The max. allowed in Gujarat State in India for a single phase domestic connection was 7.5 kW, or about 32A, enough for a 2 Ton A/c if needed.
The rules vary from state to state here in India...
In industrial connections, the "tiny" limit is 5 kVA here, above that 3 phase must be installed, and an inspection/installation certificate by a licensed contractor is needed.
I expect the sales of three phase concert equipment to be in small quantities.
And that becomes a specialist item, not something a DIY person should attempt to make or repair.
The rules vary from state to state here in India...
In industrial connections, the "tiny" limit is 5 kVA here, above that 3 phase must be installed, and an inspection/installation certificate by a licensed contractor is needed.
I expect the sales of three phase concert equipment to be in small quantities.
And that becomes a specialist item, not something a DIY person should attempt to make or repair.
The Australian poster wanted to use three phase rectifiers to get smoother (lower ripple) DC, but the practical issue was finding the right semiconductors, and other bits, to work safely at 480 * 1.414 volts, and factor of safety on top of that.
It became a case for 1200V capacity transistors, IIRC.
That thread went nowhere, I stopped watching after I realized the OP was in dreamland.
Here also, it is safer to use arrays of three amplifiers connected to three phases rather than a single amp with a three phase supply.
It became a case for 1200V capacity transistors, IIRC.
That thread went nowhere, I stopped watching after I realized the OP was in dreamland.
Here also, it is safer to use arrays of three amplifiers connected to three phases rather than a single amp with a three phase supply.