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It does not matter to the motor, just as long as the three phase voltage is what the motor specification requires.
HOWEVER..... While the motor will run in either star or delta, it will draw 3 times as much current in delta as it does in star, and will develop 3 times more torque (and power) in delta compared to star.
3 phase motors are often started in star, as it draws less current and is less likely to blow fuses, damage contacts and upset the supply system due to voltage drops. When the motor is near full speed, the motor is switched to delta connection for full power. This is called star-delta starting, and is suitable for light, low inertia loads such as fans or pumps. Because of the motor's reduced startup torque, it shouldn't be used for compressors, machines with heavy flywheels, or machines that come onto load before they reach full speed. Motors designed for star-delta starting will have 6 live terminals in their connection box.
Let's get a little bit technical. In star, each winding has L-N voltage across it (about 58% of the L-L voltage applied when in delta) - in Australia, our voltage from the active (live wire) to the neutral (return wire) is 230 volts, and the voltage from one active to another active is 400 volts. (230 / 400 is about 0.58, or 58%. and 400 / 230 is 1.73 or 173%). Connecting a motor in star puts 230 volts across each winding, and connects ONE winding to each supply phase. when running, it draws (say) 10 amps, and develops about 6 kW / 8HP. In delta, each winding has 400 volts across it, and each supply line powers 2 windings, so the current increases by 1.73 (400 volts compared to 230 volts) and again by 1.73 (2 windings on a 3 phase system draw 1.73 times more current than one winding.) 1.73 squared is 3 - so in delta, the motor draws 3 times more current (30 amps), and delivers 3 times more power (18kW / 24HP).
Some motors are designed to be operated ONLY in star - they may have a label advising you of this, or they may have only one value of voltage and current on the nameplate. They will also usually have only 3 terminals inside the connection box. If you suspect that the motor is 'star only', but want to make sure, connect the motor in delta, and check the running current as soon as the motor is up to speed; if it is drawing more than the nameplate current, or the motor is noisy in delta, but not in star, stop the motor immediately and reconnect it in star, or the motor WILL burn out very quickly.
Not really because the voltage across the winding coils are at a lower value than when running. The voltage is reduced by the inverse of the square root of 3 or 57.7% of full voltage. On a 480 volt motor the wye voltage will be 277 volts. The amperage will be reduced by 57.7 percent and the starting torque will be reduced by 33 percent while in the star configuration.
The timer should be set to change to the delta configuration as soon as the motor's RPM is going as fast as it can in the star configuration. You have to remember, the connected load is based on the motor operating in the delta configuration to develop it rated horsepower.
With the new technology today many of these types of starters are being replaced with soft start controllers.
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Can you run a star motor in delta?
Delta motors should have more starting current than Wye (Star) motors because Delta motors have two windings to take current per phase -- they are wired Phase to Phase. Star motors have only one winding per phase -- they are wired Phase to Neutral.
How star delta helping motor from overheat?
star delta motors start as a Y for 3 phase so the windings that normally see 480 volts see 277V a relay switches to delta then it runs as a normal delta motor the reduces the starting current by about 60% for 3 phase
Are contactor points and bimetallic strip connected to the star delta starter of 3 phase induction motor?
yes
What device may be wired into the starting circuit of a motor to improve the starting torque?
I assume a 3 phase, AC induction motor. A star delta starter or a soft starter can be used. A soft starter is better compared to a star delta starter, but it is more expensive.
When is a motor in star or delta connection?
Star (or wye) connection is where each of the three phases has a fourth conductor, neutral, as its current return. Current flow in this configuration is phase to neutral, which is also grounded back at the distribution center. There will be five total connections, phase A, B, and C, neutral, and (protective earth) ground. Delta connection is where each of the three phases uses the prior phase as its current return. Current flow in this configuration is phase to phase, and there is no neutral, though there is still a ground. There will be four total connections, phase A, B, and C, and (protective earth) ground.
Can you run a star motor in delta?
Delta motors should have more starting current than Wye (Star) motors because Delta motors have two windings to take current per phase -- they are wired Phase to Phase. Star motors have only one winding per phase -- they are wired Phase to Neutral.
In a star-delta starter what could be the problem if the motor does not rotate in star but rotates in delta?
One of the three phase contacts in the star contactor could be burned open or just open not allowing the motor to start because of a single phase condition. The time interval between star and delta connections could be small enough that the motor heaters will not catch the single phase condition and trip. When the motor goes into delta (which is now across the line starting) all of the three phase contacts in the contactor close and the motor starts.
Star delta starter for 3 phase induction motor?
A star-delta starter is a method used to reduce the starting current drawn by a 3-phase induction motor. It involves initially connecting the motor windings in a star configuration for starting, and then switching to a delta configuration for running. This helps to minimize voltage drops and prevents excessive current flow during start-up.
How do you wire a three phase motor with two speed?
Star and delta connection
How star delta helping motor from overheat?
star delta motors start as a Y for 3 phase so the windings that normally see 480 volts see 277V a relay switches to delta then it runs as a normal delta motor the reduces the starting current by about 60% for 3 phase
Should a star-delta motor be supplied wye or delta power?
A star-delta motor should be supplied star-delta.Wye is simply another name for star. Star-delta motors use a star or wye configuration to start, and a delta configuration to run. This reduces the voltage on the windings during the high current starting time.
IWant to see the connection of the daigram Star and Delta connections?
Google star delta motor connections. If a motor is wired in star-delta (Yd), it starts up with lots of torque and then switches over to delta for normal "running". This is because the start-up current per phase when delta connected is much larger than star.
How does a star winding shifts to a delta winding in a three phase motor?
To shift from a star winding to a delta winding in a three-phase motor, the connections between the windings need to be rearranged. In a star winding, the ends of the windings are connected to a common point (neutral), while in a delta winding, each winding end is connected to the start of the next winding. By physically switching the connections, the motor can be reconfigured from star to delta winding.
What can be done with the help of star and delta conversions?
Using star delta method of wiring you can run high rated motor with out any high starting current. Star connection can provide 3 phase power as well as single phase load
How can you include phase failure relay in your star delta motor starter circuit?
The star delta motor starter circuit has to have a control voltage to energize the motor magnetic contractors. A phase failure relay monitors all three phases of the incoming supply lines. The phase failure relay also has auxiliary contacts on it. There are usually two sets of "C" form contacts. The control voltage for the starter circuit must be connected across the normally open (N.O.) contacts of one of these two sets. When the phase monitor is energized these N.O. contacts close supplying the control voltage to the circuitry of the star delta starters. If there is a phase interruption, phase reversal or phase loss, the phase failure relay will de-energize and the N.O. contacts will go back to their de-energized state. If the star delta motor starter is in use at the time, its control circuitry voltage will be lost and the delta motor magnetic contactor will open. The opening of this contactor will disconnect the motor from the failed three phase supply.
Are contactor points and bimetallic strip connected to the star delta starter of 3 phase induction motor?
yes
What is the star delta working principle?
when starting a 3 phase induction motor,first start with star connection,because reduced current is being applied and after start change it to delta connection then. full line current is applied to the motor.
