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240v is it more effecient
- Thread starter uberbud
- Start date
K
kokua
switching to 240 will not reduce your electricity usage one bit and won't reduce your bill. The electric company charges by the watt. Swithcing to 240 will allow you to run more ballasts on the same circuit. Thats it.
Your circuits are based on amps. 15 amps, 20 amps, etc... Remember Watts = Amps x Volts....so by doubling your volts to 240 you reduce your amps while the watts is constant. a 15 amp circuit can only run one 1000 watt ballast at 120, but the same circuit can push 2 1000 watters if run 240.
Check out this nice thread on understanding electricity.
http://www.icmag.com/ic/showthread.php?t=16384&highlight=whirled+peas
Your circuits are based on amps. 15 amps, 20 amps, etc... Remember Watts = Amps x Volts....so by doubling your volts to 240 you reduce your amps while the watts is constant. a 15 amp circuit can only run one 1000 watt ballast at 120, but the same circuit can push 2 1000 watters if run 240.
Check out this nice thread on understanding electricity.
http://www.icmag.com/ic/showthread.php?t=16384&highlight=whirled+peas
I.M. Boggled said:You now understand electricity. That's all there is to it.
Get yourself a tool belt, a bad attitude and a wiggy, and you can be an electrician.
Be sure to mumble things about potential differentials or power factor and you can pass as an electrical engineer.
One good thing about 240 is that it is marginally safer. The wires are a much larger gauge and there is less resistance, therefor less heat. This is especially benefical in an older home. The insulation on the wires could be cracked with age or even loose. If the dryer plug or stove plug is used you have a much safer setup, even if those plugs were wired 40 years ago. Just my 2 cents.
TGT
TGT
Kokua and TGT are correct. The 240v circuit being more efficient in terms of wattage consumption over a 120v circuit is a total misconception. The formula that Kokua posted is fact. The wattage remains constant. The reason 240 is used to light large parking lots is not to save on wattage, but to reduce amperage to run a higher # of lights. High Times published an article saying that 240 circuits will reduce your electricity bill. This is totally false. I wrote to High Times feedback on the subject, but they never published it. I have even had electricians and maintenance men tell me "240 will save you money and you can watch your meter turn slower. I can't explain why, but it's true." What?? The simple formula amps x volts = watts is irrefutable.
Peace, Mr.M
Peace, Mr.M
D
DB2004
A 240V ballast (1000watts) draws same amperage as 120V ballast. With 240V, the amperage is split in two over both 120V hots. Each 120V is carrying approximately 4.5A (x2) is 9A. 120V ballast draws 9A. There is a misconception about this, you are still drawing 9 Amps. It's not that you have 240V hot and a neutral, it's two 120V feeds.
Best Regards
DB
Best Regards
DB
Human target
New member
Meters read usage based on difference of potential between the loads and the neutral. Investigate the concept of load balancing and you'll see why you can save money running 240 volts (or 208/480 if you are using a three phase supply). Doesn't mean you will, but it is possible to do.
Some of us really are EE's and don't just mumble.
Some of us really are EE's and don't just mumble.
it runs more efficient, helps balance the load on both phases.
that, in turn, gives you a better power factor.
power factor is basically an efficiency ratio.
the higher your power factor, the cheaper your electric.
so, the sparky's who mentioned this to you, were dead on.
that, in turn, gives you a better power factor.
power factor is basically an efficiency ratio.
the higher your power factor, the cheaper your electric.
so, the sparky's who mentioned this to you, were dead on.
Iluvtomatoes
Member
I don't know what you guys are smoking but 240v is more efficient than 120v. The reason: you're pulling the same load over 2 sets of wires instead of one, and usually they are a larger gauge. This reduces the overall electrical load, reducing impedance, and any heat buildup thereby being more efficient.
If it wasn't more efficient for heavy electrical appliances why would builders install it on all high draw equipment?
downside with 240v--much more dangerous with pools of water around.
If it wasn't more efficient for heavy electrical appliances why would builders install it on all high draw equipment?
downside with 240v--much more dangerous with pools of water around.
K
kokua
yeah...if your running 4 lights you might see a small difference...small. one light...NO DIFFERENCE!
As far as how you're charged for electricity a watt is a watt. All utility companies charge by how many kilowatt-hours you use. If two appliances use the same number of watts then you'll be charged the same amount for using either of them, regardless of how many volts they use.
Remember that Volts x Amps = Watts. A device that runs on 240V draws half as many amps as a similar wattage device that runs on 120V. Bottom line, watts are watts, and watts are what you get charged for. Volts don't matter.
one light...NO DIFFERENCE!As far as how you're charged for electricity a watt is a watt. All utility companies charge by how many kilowatt-hours you use. If two appliances use the same number of watts then you'll be charged the same amount for using either of them, regardless of how many volts they use.
Remember that Volts x Amps = Watts. A device that runs on 240V draws half as many amps as a similar wattage device that runs on 120V. Bottom line, watts are watts, and watts are what you get charged for. Volts don't matter.
bghydro said:
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Ohm's law, bitches. No getting around that.
240V will wake you up much faster than a zap from 110V!
You can decrease wire size because it draws less current, a real money saving factor for some applications.
DB2004, no you are wrong. The 240V draws half the current. Voltage and current are inversely proportional.
Ohm's Law.
High current loads definitely benefit from running 240V, because the wire size is half of what you would need for 110V.
That's why hydro transmission lines are high voltage, to drop the current and decrease the size of the lines. Could you imagine the wire guage if the transmission lines ran at 110V. You would have nothing left by the time it got to you, due to voltage drop.
240V will wake you up much faster than a zap from 110V!
You can decrease wire size because it draws less current, a real money saving factor for some applications.
DB2004, no you are wrong. The 240V draws half the current. Voltage and current are inversely proportional.
Ohm's Law.
High current loads definitely benefit from running 240V, because the wire size is half of what you would need for 110V.
That's why hydro transmission lines are high voltage, to drop the current and decrease the size of the lines. Could you imagine the wire guage if the transmission lines ran at 110V. You would have nothing left by the time it got to you, due to voltage drop.
D
DB2004
I spoke to my instructor at school and it's you who's wrong. If you clamp an ammeter onto both 120V feeds to a ballast that is 240V, the amperage is the same on both lines.
DB
DB
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Well then according to you, the 240V uses twice as much power.
240v x 9 amps = 2160watts
120V x 9 amps = 1080watts
Power = Volts x Amps
Explain that one then....
It's the total of the load, not what is on each leg of the 220.
I think you fail to understand that each 110v leg alternates 4.5 amps, they do not add together.
240v x 9 amps = 2160watts
120V x 9 amps = 1080watts
Power = Volts x Amps
Explain that one then....
It's the total of the load, not what is on each leg of the 220.
I think you fail to understand that each 110v leg alternates 4.5 amps, they do not add together.
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G
Guest
It says on the ballasts themselves,4.5A at 240V 9.2A at 120V.I think your instructor was referring to sizing conductors by ampacity not total ampacity.
Joe A. Grower
Active member
I'm no EE (actually I'm an AE), but I could see how it would be possible to design a more efficient 240V ballast. I read somewhere that the internal voltage used to run a HID lamp is around 4,000 - 5,000 volts on ignition, and then something in the range of 200 - 400 volts RMS during operation. Since standard residential electrical service is either 120V or 240V, there obviously is a transformer inside the ballast that is raising the the voltage from the input level to the internal operational level.
If the transformer starts with power at 240V, then it isn't going to have to raise the voltage as much as it would if starting from 120V. Thus a 240V ballast could be designed to be more efficient than than a 120V ballast. The key word here is "could." I suspect one would need to design the ballast to take advantage of the higher input voltage in order to have a significant savings.
How much power could be saved? Well, first you have to look at how much power the ballast is eating in the first place. I understand the old magnetic coil ballasts would use about 1,200 W to run a 1,000 W HID lamp. The lamp itself is going to always use 1,000 W, regardless of ballast type, so any power savings is going to come out of the 200 W the ballast is wasting. With digital ballasts, this wasted electricity has already been substantially reduced anyway. So I suspect a specifically designed 240V ballast could only save a few percent on the power bill.
That being said, I've read forum reports on the new Lumatek 1,000 W ballast that indicate the 240V ballast runs noticeably cooler than the 120V ballast. Cooler operation usually equals less wasted electricity. So it would seem that Lumatek took advantage of the higher voltage to make the 240V-only ballast a bit more efficient.
Personally, I would doubt that the power savings really add up to much.
If the transformer starts with power at 240V, then it isn't going to have to raise the voltage as much as it would if starting from 120V. Thus a 240V ballast could be designed to be more efficient than than a 120V ballast. The key word here is "could." I suspect one would need to design the ballast to take advantage of the higher input voltage in order to have a significant savings.
How much power could be saved? Well, first you have to look at how much power the ballast is eating in the first place. I understand the old magnetic coil ballasts would use about 1,200 W to run a 1,000 W HID lamp. The lamp itself is going to always use 1,000 W, regardless of ballast type, so any power savings is going to come out of the 200 W the ballast is wasting. With digital ballasts, this wasted electricity has already been substantially reduced anyway. So I suspect a specifically designed 240V ballast could only save a few percent on the power bill.
That being said, I've read forum reports on the new Lumatek 1,000 W ballast that indicate the 240V ballast runs noticeably cooler than the 120V ballast. Cooler operation usually equals less wasted electricity. So it would seem that Lumatek took advantage of the higher voltage to make the 240V-only ballast a bit more efficient.
Personally, I would doubt that the power savings really add up to much.
The 240V model runs cooler because it draws half the amps. Current + resistance equals heat which is waste (as well as noise, or hum). Less heat also equals increased life of electronic components.
No doubt it helps to have the voltage higher when driving a high resistance circuit like an HID (tube arc gap)or a stove (elements). You run into different concerns with higher voltage like safety issues, insulation and such.
When you have twice the electromotive force you only need half the current to do the same work.
No doubt it helps to have the voltage higher when driving a high resistance circuit like an HID (tube arc gap)or a stove (elements). You run into different concerns with higher voltage like safety issues, insulation and such.
When you have twice the electromotive force you only need half the current to do the same work.
Joe A. Grower
Active member
HeadyPete said:
Actually the formula you are looking for is P = I^2 * R where P is the power lost to heat, I is the current, and R is the resistance in the power line. By doubling the voltage, you halve the current, and reduce line loss by a factor of four.
However, I doubt the difference in resistive heating from the internal wiring of the ballast is responsible for causing a ballast to run hotter or cooler. The wiring distances involved inside the ballast are VERY short (a few inches at most), so the value for R in the above equation would be very low. The heat a ballast gives off during operation is most likely due to the transformer that is stepping up the voltage to the internal operating level.
sonoma said:
I used to run a 9 kW grow for living. Maybe that isn't the biggest show in the world, but I think it qualifies me as a "pro." I could have just as easily wired my subpanel 240V as 120V, but I chose to go with 120V. By using 120V I could put each light on its own breaker, and use cheap, readily available mechanical timers to control my lights. If I had gone with 240V, I would have had to run multiple lights off a single breaker (to save space in the subpanel) and use a more expensive hotub timer, or wire my own relays, or some other tiresome bullshit. The wiring runs from my panel to the timers were less than 15', so line losses were very low. Going from 120V to 240V would have gained me nothing and would have complicated my life for no good reason.
In the end, going 120V made my light timing solution this simple:
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Thanks for the great info, Joe.
So the electronic stepping up of the voltage must run cooler than the old mag transformer stepping it up.
Power supplies have come a great distance lately. My expertise, pro audio, shows this where the new digital power amps can put out more power, with less heat weight and space in the rack. A two space rack unit can do 4 channels of audio whereas the old Crest 10004 was like 5-6 spaces and weighed well over a hundred pounds. Break your back getting out of the rack and shipped for servicing.
Cheers and great discussion...thanks!
So the electronic stepping up of the voltage must run cooler than the old mag transformer stepping it up.
Power supplies have come a great distance lately. My expertise, pro audio, shows this where the new digital power amps can put out more power, with less heat weight and space in the rack. A two space rack unit can do 4 channels of audio whereas the old Crest 10004 was like 5-6 spaces and weighed well over a hundred pounds. Break your back getting out of the rack and shipped for servicing.
Cheers and great discussion...thanks!
HeadyPete said:
they don't alternate, each hot leg at 220v will draw 4.5a continuously while it's running.
if you clamped an ammeter on it during operation, the number wouldn't deviate much from 4.5a
