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 = Kn⁄R
b) Ratio error = Kn – R⁄R
c) Ratio error = Kn – 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