Week 10

Question 1

Maximum voltage drop for motors?
How much does the motor need to perform satisfactory?
What will the voltage drop cause?

Answer 1

8% can lead to problems in motors
Needs +_5%
The voltage drop of 8% will cause a drop of 40% or more during start up, so the motor will either:
1- stall (remain stationary due to insufficient torque) with overheating or trip out
2- accelerate very slowly so the start up current will continue beyond the normal start up period
+
Power loss (waste of energy)

Question 2

Impedance of circuits is low but not negligible, when carrying load current there is voltage drop between:

Answer 2

The origin of the circuit and the load terminals

Question 3

Correct operation of a load depends on

Answer 3

The voltage_at it’s terminals being maintained at a value close to its rated value, so it is important to determine the conductors that in full load current the load terminal voltage within required limits