The original purpose of a 'high leg' service was to supply motor loads and lighting from a single service. As posted above, motors are dumb. If the phase to phase voltage is in the motor's tolerance, they will run just fine.
What is the purpose of the high leg on a duct?
The high leg is simply part of the 3 phase network and useable in any 3 phase or single phase 240 volt equipment. The high leg is not used ever for 120v loads. yes and your also not suppost to make love to 480 v bus duct.
Is elevating your legs good for your health?
Because of this, it often feels good to kick back and relax once in a while. It’s even possible that you can gain some health benefits from putting your feet up and elevating your legs. In this article, we’ll take a closer look at the health benefits of elevating your legs, what conditions it may help, and the precautions to be aware of.
What does it mean when your legs are elevated?
Elevating your legs places them above the level of your heart. This means that gravity is now working in your favor. This may help improve blood flow in the veins in your legs. Swelling can happen due to the accumulation of excess fluid ( edema) or inflammation.
What are the health benefits of lying down with your legs elevated?
Sitting or lying down with your legs elevated can have several potential health benefits. Let’s explore them. Elevating your legs can help improve blood flow in your lower extremeties. How? The simple answer is gravity. Oxygen-depleted blood returns to your heart through your veins.
What is the point of a high leg?
In some ways, the high leg delta service provides the best of both worlds: a line-to-line voltage that is higher than the usual 208 V that most three-phase services have, and a line-to-neutral voltage (on two of the phases) sufficient for connecting appliances and lighting.
What phase is the high leg supposed to be?
B” phaseThe NEC Code requires that the high leg be identified by an orange color (it was often referred to as a red-leg delta) or by other effective means and is usually the “B” phase.
What voltage is the high leg?
approximately 208 voltsThe high leg voltage magnitude is approximately 208 volts with an angle of negative 30 degrees when a reference of zero degrees for the A Phase voltage (VAB) is used.Aug 26, 2019
What 3 phase system has a high leg?
What is High Leg Delta? High Leg Delta (also known as Power Leg or Wild Leg) is a three phase, four wire power distribution system used in commercial buildings in North America especially in rural and older installations.
What is a Delta breaker?
A Delta Breaker is a load-center breaker with 2 plug in stabs and a third wire from the third terminal that goes to the third leg of a transformer. This allowed you to use a single phase loadcenter and get three phase power by running a third wire back to the transformer.Jan 7, 2010
What is the difference between 208 and 240?
2:596:25How is 208 volts different than 230/240 volts? - YouTubeYouTubeStart of suggested clipEnd of suggested clipStandpoint when you're using 208 to power a motor or appliance. That's designed for 208 or 240. You'MoreStandpoint when you're using 208 to power a motor or appliance. That's designed for 208 or 240. You're generally not going to get the full capacity or the full output.
Can you run 208V on 240V?
In short, just because a 208v motor may be designed to run on 230v or 240v systems by using two power legs from the utility source, that doesn't mean that it will provide the same output efficiency. You will see differences in performance if you try to use 208v when 240v is typically required.Feb 16, 2021
Is 240V 3 phase?
240V power is used in the US and parts of the world. In the US 120 / 240V 1 Phase 3 Wire is the standard for homes and 240V 3 Phase Open Delta is the standard for small buildings with large loads. In parts of the world 240V Single Phase 2 Wire is the standard for homes.Jun 26, 2016
Does 3 phase 480V have a neutral?
480V 3 Phase Delta is a 3 Wire power configuration and does not include a neutral wire.Dec 4, 2017
How do you get 277 from 480?
So if you're wondering how we get numbers like 208, 277 you use 1.732 (because they're three-phase voltages). For example 480 / 1.732 = 277 volts, and 120 x 1.732 = 208 volts.
What does open delta mean?
Definition of open-delta connection : a usually temporary or emergency connection of a three-phase electrical circuit in which one of the three transformers is omitted and its load carried by the two transformers. — called also V-connection.
Why do you elevate your legs?
Some of the key benefits include improved blood flow, reduced inflammation, and lower pressure in the veins in your legs. You can use leg elevation to help ease symptoms from varicose veins and to reduce swelling during pregnancy. It may also be a helpful way to prevent blood clots ...
Why do you have to elevate your legs to get blood to your heart?
When you’re sitting or standing, oxygen-depleted blood in your legs must also work against gravity in order to return to your heart. Elevating your legs places them above the level of your heart. This means that gravity is now working in your favor. This may help improve blood flow in the veins in your legs.
What is a DVT in the leg?
DVT is when a blood clot forms in one of the deep veins of your leg. These clots can block blood flow, leading to leg swelling or pain. This clot can also move to your lungs, causing a pulmonary embolism. Varicose veins.
What is the name of the blood clot under your skin?
Superficial thrombophlebitis is a blood clot in a vein just under your skin that can cause swelling and tenderness. While some are low-risk, others may be associated with deep vein thrombosis. Deep vein thrombosis (DVT). DVT is when a blood clot forms in one of the deep veins of your leg.
Why do my legs swell up?
Swelling can happen due to the accumulation of excess fluid ( edema) or inflammation. It’s possible that injuries or certain health conditions may cause swelling to occur in your legs. In the same way that it helps improve blood flow, elevating your legs above the level of your heart may help excess fluid to drain away more effectively.
How to lower pressure in legs?
Elevating your legs can help lower the pressure in your legs by allowing blood that has pooled to drain away. If you’ve been standing for a while, sitting down with your legs raised can also help ease pressure and tenderness of tired feet.
What causes blood to pool in legs?
Chronic venous insufficiency (CVI). CVI happens when blood can’t effectively return to your heart, which causes it to pool in your legs. It can cause a variety of symptoms in your legs, including pain, swelling, and varicose veins.
Overview
High-leg delta (also known as wild-leg, stinger leg, bastard leg, high-leg, orange-leg, red-leg, dog-leg delta) is a type of electrical service connection for three-phase electric power installations. It is used when both single and three-phase power is desired to be supplied from a three phase transformer (or transformer bank). The three-phase power is connected in the delta configuration, and the …
Supply
High-leg delta service is supplied in one of two ways. One is by a 3-phase transformer (or three single-phase transformers), having four wires coming out of the secondary, the three phases, plus a neutral connected as a center-tap on one of the windings. Another method (the open delta configuration) requires two transformers. One transformer is connected to one phase of the overhea…
Explanation
Consider the low-voltage side of a 120/240 V high leg delta connected transformer, where the 'b' phase is the 'high' leg. The line-to-line voltage magnitudes are all the same:
Because the winding between the 'a' and 'c' phases is center-tapped, the line-to-neutral voltages for these phases are as follows:
Advantages
If the "high leg" is not used, the system acts like a split single-phase system, which is a common supply configuration in the United States.
Both three-phase and single split-phase power can be supplied from a single transformer bank.
Where the three-phase load is small relative to the total load, two individual transformers may be used instead of the three for a "full delta" or a three-phase transformer, thus providing a variety o…
Disadvantages
In cases where the single-phase load is much greater than the three-phase load, load balancing will be poor. Generally, these cases are identified by three transformers supplying the service, two of which are sized significantly smaller than the third, and the third larger transformer will be center tap grounded.
One of the phase-to-neutral voltage (usually phase "B") is higher than the other two. The hazard o…
Applications
It is often found in older and rural installations. This type of service is usually supplied using 240 V line-to-line and 120 V line-to-neutral. In some ways, the high leg delta service provides the best of both worlds: a line-to-line voltage that is higher than the usual 208 V that most three-phase services have, and a line-to-neutral voltage (on two of the phases) sufficient for connecting appliances and lighting. Thus, large pieces of equipment will draw less current than with 208 V, r…
See also
• Transformer
• Three-phase electric power
• Electric power distribution
• Mains electricity
• Mains electricity by country