### Create an Account

Home / Questions / 1 In an ac machine the insulation of the windings is a critical part List the item below t...

# 1 In an ac machine the insulation of the windings is a critical part List the item below that does NOT affect the winding insulation The speed of the rotor magnetic field

1. In an ac machine, the insulation of the windings is a critical part. List the item below that does NOT affect the winding insulation.

The speed of the rotor magnetic field
Mechanical shock
Limiting the maximum power
Air circulation inside the motor
Following NEMA standards
Mechanical vibration

 2. (TCO 5) For synchronous machines, which item below is NOT true?
There are field and armature windings.
The armature windings have a very low resistance.
They can be generators or motors.
The brushes will have a voltage drop.
They will have slip rings or brushes.
They will have ac applied to both windings.
 3. What is the speed in RPMs for an 8-pole synchronous motor with an input frequency of 50 hertz?
 4. A three-phase, delta connected, 60-Hz, two-pole, synchronous machine has a stator with 2000 turns of wire per phase. What rotor flux would be required to produce a terminal (line-to-line) voltage of 2 kV?
 5. A 240-V, 50 Hz, eight-pole, synchronous motor draws 40 A from the line at unity power factor and full load. If the motor is lossless, what is the output torque of the motor in Nm?
 6. A three-phase, two-pole winding is installed in six slots on a stator. There are 50 turns of wire in each slot of the windings. All the coils in each phase are connected in series, and the three phases are connected in a delta. The flux per pole in the machine is 0.10 Wb, and the speed of rotation of the magnetic field is 3000 r/min. What is the frequency of the voltage produced in this winding?

Jul 27 2020 View more View Less