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Why does a 120V-240V dual voltage single phase table saw motor produce 4 times more torque at 240V than at 120V?
Wiki User
∙ 15y ago
I believe it has to do with the windings in the motor. When wired to 120V, half the motor has a positive polarity and the other half has a negative polarity. Then as the current alternates (60 hertz AC) the polarity flips, the magnetic poles oppose each other and cause the motor to spin. I think in a 240v winding the motor is in quadrants instead of halves. So it would be like have 4 magnets opposing each other instead of two and you have double the voltage. The calculation for electrical power (which is converted to torque) is voltage-squared divided by the resistance. If the voltage is doubled, the power is increase by 2-squared, or quadrupled. In reality, the torque produced will be slightly less than 4 times more (because some of the power is lost as heat), but it should be pretty close. -- The second answer is the best answer. The first answer could suggest several things, depending on how you read it. Nonetheless, they are all incorrect. The power calculation (in Watts) is really all you need to do. Voltage squared, divided by resistance. Resistance stays the same, so power quadruples when voltage doubles. If the motor spins at the same speed, then torque should effectively be linear with power, aside from the extra heat created in the components from the higher current.
Wiki User
∙ 15y ago
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Who to increase torque of ac motors?
ac voltage
What type of rotor is used in a capacitor-start motor?
Types of MotorsThere are different types of Capacitor-start motors designed and used in various fields. They are as follows:Single-voltage, externally reversible type,Single-voltage, non-reversible type,Single-voltage reversible and with thermostat type,Single-voltage, non-reversible with magnetic switch type,Two-voltage, non-reversible type,Two-voltage, reversible type,Single-voltage, three-lead reversible type,Single-voltage, instantly-reversible type,Two speed type, andTwo-speed with two-capacitor type.These motors can be used for various purposes depending upon the need of the user. The starting, speed/torque characteristics of each of the above motors can be analyzed before employing them in work.
Performance curve of a single phase induction motor?
The performance curve can be a graph of torque versus speed. The torque is zero at zero speed and also at the synchronous speed. Normally an induction motor operates at 90-97% of the synchronous speed, where the slip is between 10% and 3%. In this region the torque is proportional to the slip. As the torque is increased the speed falls until the motor stalls and the speed drops to zero. Below the stalling speed the torque rises between zero speed and the stalling speed. Because the torque is 0 at 0, a single-phase induction motor needs a separate starting winding fed by a starting capacitor to produce a little positive torque that starts the motor.
What is motor rated torque?
It is the twisting force that a motor can produce when it is running.
Calibrated torque wrench method?
the most accurate calibrated torque wrench was using the TWT torque wrench tester products that produce by Stahlwille. Its also called transducer.
Can a torque be balanced by a single force?
The effect of a torque is to produce angular acceleration and that of the force is to produce linear acceleration. Since the effects of both torque and force are entirely different, therefore, a torque cannot be balanced by a single force.
A torque acting on an object tends to produce what?
A torque acting on an object tends to produce rotation.
Who to increase torque of ac motors?
ac voltage
How floating condition of synchronous motor occurs?
at the time of starting when syncchronous torque is zero , i.e. when the motor starts with the help of starting torque , the armature current required to produce sync. torque is zero. If V = E(b) i.e. When back emf E(b) equals supply voltage.
Why does a three phase system provide constant torque?
It doesn't. A 3-phase motor will provides constant torque because the three alternating fields produce exactly the same effect as a single rotating field.
Why a three phase system provides constant torque?
It doesn't. A 3-phase motor will provides constant torque because the three alternating fields produce exactly the same effect as a single rotating field.
What type of rotor is used in a capacitor-start motor?
Types of MotorsThere are different types of Capacitor-start motors designed and used in various fields. They are as follows:Single-voltage, externally reversible type,Single-voltage, non-reversible type,Single-voltage reversible and with thermostat type,Single-voltage, non-reversible with magnetic switch type,Two-voltage, non-reversible type,Two-voltage, reversible type,Single-voltage, three-lead reversible type,Single-voltage, instantly-reversible type,Two speed type, andTwo-speed with two-capacitor type.These motors can be used for various purposes depending upon the need of the user. The starting, speed/torque characteristics of each of the above motors can be analyzed before employing them in work.
Is torque directly proportional to applied voltage?
Current is directly proportional to applied voltage. Ohm's law.
How does a large force produce a small torque and it is possible for a small force to produce a large torque?
Torque is the product of (force) x (distance from the center of rotation).So with a distance from the center that's large enough or small enough,any force can produce as much or as little torque as you want.
What human body part may produce torque?
Any time there is a force, there can be torque.
What is the purpose of capacitor in a single phase motor?
the purpose of the capacitor is to create a phase difference between main winding current and axillary winding. this would produce a rotating constant magnetic field which is required to produce the torque.
What is relation between speed of generator and its voltage and torque on generator shaft and current produced by generator?
power = torque * rpm
