DC motors are usually seen in applications where the motor speed needs to be externally controlled. AC motors work best in applications where power performance is sought for extended periods of time. All DC motors are single phase, but AC motors can be single phase or three phase.
AC and DC motors use the same principle of using an armature winding and magnetic field except with DC motors, the armature rotates while the magnetic field doesn’t rotate. In AC motors the armature does not rotate and the magnetic field continuously rotates.
In some applications today, DC electric motors are replaced by combining an AC electric motor with an electronic speed controller, known as variable frequency drives. DC electric motors are replaced with an AC electric motor and an electronic speed controller because it is a more economical and less expensive solution.
DC electric motors have many moving parts that are expensive to replace, and DC electric motor repair is usually more expensive than using a new AC electric motor with an electronic controller.
In our experience, combining an AC motor and drive proves to be the most cost effective solution for mostapplications. When servicing our customers in the field, we often recommend looking at the SMVector Series Variable Frequency Drive in combination with a three phase AC motor.
When it is has a probability value of 0.1587, it means
that 15.87% of the total sample is below z = -1 or there is a chance that the
selected sample has a 15.87% chance of being below z = -1. Actually all the
choices are telling the same thing in different way.
Answer:
E. All of the above
Answer:
Comprehensive trials have not been completed to support the company's claim.
Explanation:
But, even if there have been no medical trials there are some shreds of evidence from personal accounts.
Answer: Look at the explanation.
Explanation: An environmental consequence could be our land. The more land we use for agriculture results in loss of biodiversity. Slash-and-burn kills many trees and plant life. These trees are home to many small animals and now they are homeless and will die unless they adapt and find a new land. A social consequence could be food deserts. Food deserts are caused by and increase poverty and starvation. Nonexistent stores in rural areas do not help the population. People starve and barely have another way of getting healthy food. They rely on fast food chains which do not help with health.
Answer:
what does it need to be about?