- With reference to a 440 Volt, 3-phase motor supplied with six terminal connection in the terminal box:
(a) sketch a Delta connection, showing the relationship between phase and line voltages;
(b) sketch a Star connection, showing the relationship between phase and line voltages;(2)
(c) state the relative speed of both connections;(2)
(d) sketch and label the terminal link connections so the motor will run in permanent Delta mode.(4)
- With reference to induction motor starters:
(a) state when a STAR/DELTA starter may be required;
(b) describe the operation of a STAR/DELTA starter;
(c) explain why the motor configuration is changed from STAR to DELTA.
4.(a) Using Worksheet, sketch how an a.c. motor would be connected in EACH of the following:
(i) Star;(3)
(ii) Delta.(3)
(b) State the probable consequences of connecting a motor in star instead of delta.(4)
Question 3.
Although all can show a triangle and star shape many are unable to transfer this to a terminal box layout. Few consider the effect on the distribution system od a large motor starting.