metal rectifier

mercury arc rectifier

solid state rectifier

tunger rectifier

it does not require any maintenance

the generated D.C. remains completely isolated from the A.C.

its efficiency is very high

none of these

single-phase type only

three-phase type only

single or three phase type

both single and three phase type

d.c. supply

a.c. supply

mechanical power

either of the above three

mercury vapour lamp

arc lamp

sodium vapour lamp

fluorescent lamp