Page 327 - Electronic Mechanic - TP - Volume - 2

ELECTRONICS MECHANIC - CITS

4 For field control method:-

• Stepnos.1,2 &3of armature voltage control method are repeated.
• The armature rheostat is varied such that the rated voltage is applied across the armature terminals.
• The field rheostat is gradually cut in steps so that the field current is varied in steps of 0.05A and the
corresponding value of speeds are noted.
• Step no.3 is repeated until the fieldrheo statis completely CUTIN.
• Step no.3 and 4 are repeated foranarmaturevoltageof200V.
• The field rheostat is brought back to CUT OUT ,the armature rheostat to CUT IN position and the supply
switch is opened.
Field control method
Table

Armature voltage =
Sl.No Field current In Volts Speed In rpm

310
CITS : E & H - Electronics Mechanic - Exercise 218&219