Errors in Current Transformers

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Errors in Current Transformers”.

1. Errors are introduced in Current Transformers.
a) True
b) False

2. Ratio error is defined as ___________
a) Ratio error = ^K_n⁄_R
b) Ratio error = ^{K_n – R}⁄_R
c) Ratio error = K_n – R
d) Ratio error = ¹⁄_R

3. Phase angle in a C.T. is defined as ____________
a) 180π[ImcosδnIs] degrees
b) 180π[IcsinδnIs] degrees
c) 180π[Imcosδ–IcsinδnIs] degrees
d) 180π[Imsinδ–IccosδnIs] degrees

4. Phase angle error is given by ____________
a) 180π[1nIs] degrees
b) 180π[ImIs] degrees
c) 180π[Imn]degrees
d) 180π[ImnIs] degrees

5. Ratio error is due to _________
a) iron loss
b) C.T.
c) magnetising component
d) supply voltage

6. Phase angle error is due to _________
a) C.T.
b) magnetising component
c) iron loss
d) supply voltage

7. In power measurements 180° phase shift is required.
a) True
b) False

8. Errors in a C.T. can be minimised by _________
a) making use of laminations
b) having low reactance
c) increasing the secondary winding turns
d) decreasing the primary winding turns