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How do you fuse dry type transformers for an open delta system used to transform 480 Volt 3 phase to 120-240 Volt 3 phase 4 wire?
Wiki User
∙ 14y ago
one transformer is sized for 57.7% of the three phase load, the other carries 57.7 % of the three phase load plus all of the single phase load.
find out the kva of your loads
then size your Transformers
find the rated FLA of the transformers on the primary and secondary with Watt's law
add the individual currents with vectors to find the phase currents primary and secondary
then apply NEC 430.3(B)
Wire is sized to carry the load and be protected by OCPD
make sure the wire is protected via 240.21 (B) or (C) tap rules.
There are too many possible combinations of primary/secondary protection and tap rules to give a complete answer, your solution will vary based on distance between overcurrent devices and the transformers and also with your choices in regards to transformer KVA sizing. A simpler solution that is lighter, off the shelf, simpler to install and probably cheaper is to use a single three phase transformer with a 240 wye/delta connection. I think that would also gain you some noise isolation.
Wiki User
∙ 14y ago
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What is open delta?
USE FOR 3 PHASE SUPPLY REQUIREMENT BUT WITH ENGINEERING ECONOMICS BACKGROUND. FOR EXAMPLE YOUR REQUIREMENT IS ONLY 500 KVA AT THE MOMENT BUT HAVE PLANS FOR EXPANSION IN THE FUTURE THEN YOU HAVE TO INVEST ONLY FOR 2 NOS. OF 333 KVA TRANSFORMER CONNECTED LIKE REMOVING ONE LEG OF DELTA SHAPE. YOU WILL HAVE A CAPACITY OF 3 X 333KVA DIVIDED BY SQUARE ROOT OF 3 = 577 KVA(57.7% OF CLOSED DELTA) WHICH SATISFY YOUR PRESENT REQUIREMENT. IN THE TIME YOU WANT TO EXPAND LOAD - JUST ADD ONE UNIT 333 KVA TO BE A CLOSED DELTA IT WILL GIVE YOU 999=1000KVA CAPACITY(42.3% MORE).
Can you bank three single phase transformers in a delta to grounded wye with one transformer having a different impedance?
yes
Can you hook up a delta to delta transformer to be a delta to wye transformer?
The open Delta or V-Connection transformer is an improvement of the 1 three-phase transformer. The open Delta transformer can restore power in a Delta-Delta three-phase bank when one of the three single-phase transformers, which can be individually disconnected and replaced in case of failure, breaks down. The open Delta transformer then allows functionality to be restored, but at a reduced power of 57.7 of the original power.
The speed of an electric motor can be controlled by?
By using the star- delta starting methodBy using variable rhoestatsBy using auto transformers
What is the difference between an open delta and an open wye connection?
An open delta connection is a delta connection with one phase removed, but still supplied with three line conductors. An open wye is a wye connection with one phase removed, supplying a three line conductors and a neutral conductor. An open-delta/open-wye is a method of providing a reduced-load three-phase supply using just two single-phase transformers, rather than the preferred method of using three single-phase transformers.
What is the laplace transform of a unit step function?
a pulse (dirac's delta).
What is Dy transformer step up or step down?
Theoretically, a delta-wye transformer can step up or step down. In Europe, tertiary distribution transformers are step-down delta-wye transformers, so that the secondary side offers a three-phase, four-wire, system offering 400 V line-to-line and 230 V line-to-neutral.
What are the Laplace transform of unit doublet function?
The Dirac delta function.
Why would two 240 volt transformers on different primary phases have their secondary windings wired in series?
What you are probably looking at is a 240 volt three phase system with the secondaries wired in an open delta configuration.
What is open delta?
USE FOR 3 PHASE SUPPLY REQUIREMENT BUT WITH ENGINEERING ECONOMICS BACKGROUND. FOR EXAMPLE YOUR REQUIREMENT IS ONLY 500 KVA AT THE MOMENT BUT HAVE PLANS FOR EXPANSION IN THE FUTURE THEN YOU HAVE TO INVEST ONLY FOR 2 NOS. OF 333 KVA TRANSFORMER CONNECTED LIKE REMOVING ONE LEG OF DELTA SHAPE. YOU WILL HAVE A CAPACITY OF 3 X 333KVA DIVIDED BY SQUARE ROOT OF 3 = 577 KVA(57.7% OF CLOSED DELTA) WHICH SATISFY YOUR PRESENT REQUIREMENT. IN THE TIME YOU WANT TO EXPAND LOAD - JUST ADD ONE UNIT 333 KVA TO BE A CLOSED DELTA IT WILL GIVE YOU 999=1000KVA CAPACITY(42.3% MORE).
Can you bank three single phase transformers in a delta to grounded wye with one transformer having a different impedance?
yes
Can you join two of single phase to two phase power system?
This is a rubbish questionTwo single phase transformers can be combined together to make a three phase system. It does not become a two phase system. Look up information of an open delta wired distribution system to see how they are tied together.See related links below.
How do you change 3 1phase transformer in to 3 phase?
Three-phase transformation can be obtained using two Transformers, by connecting them in what is known as an 'open delta' connection.
How do you find angular displacement of transformer?
Angular displacement (sometimes called phase displacement) applies to three-phase transformers, whether a single three-phase transformer, or three single-phase transformers connected as three phase transformer bank. It is, to a three-phase transformer what additive/subtractive polarities are to a single-phase transformer.Angular displacement is one of a number of conditions that must be the same before two three-phase transformers (or transformer banks) are paralleled.'Angular displacement' is the angle by which the secondary line-to-line voltage lags the primary line-to-line voltage.Angular displacements for common connections are as follows:delta/delta transformers have an angular displacement of 0o or 180owye/wye transformers have an angular displacement of 0o or 180odelta/wye transformers have an angular displacement of 30o or 210owye/delta transformers have an angular displacement of 30o or 210oSo, for example, it is impossible to parallel a delta/delta or wye/wye transformer with a delta/wye or wye/delta transformer, as their angular displacements are different.Determining the angular displacement of a particular transformer configuration (wye-delta, etc.) can be done by drawing the phasor diagram for the complete transformer as follows:draw the primary phase voltagesdraw the primary line voltagesdraw the secondary phase voltagesdraw the secondary line voltagesmeasure the (angular displacement) between a secondary line voltage and its corresponding primary line voltage
Can you hook up a delta to delta transformer to be a delta to wye transformer?
The open Delta or V-Connection transformer is an improvement of the 1 three-phase transformer. The open Delta transformer can restore power in a Delta-Delta three-phase bank when one of the three single-phase transformers, which can be individually disconnected and replaced in case of failure, breaks down. The open Delta transformer then allows functionality to be restored, but at a reduced power of 57.7 of the original power.
The speed of an electric motor can be controlled by?
By using the star- delta starting methodBy using variable rhoestatsBy using auto transformers
What is the difference between an open delta and an open wye connection?
An open delta connection is a delta connection with one phase removed, but still supplied with three line conductors. An open wye is a wye connection with one phase removed, supplying a three line conductors and a neutral conductor. An open-delta/open-wye is a method of providing a reduced-load three-phase supply using just two single-phase transformers, rather than the preferred method of using three single-phase transformers.
