Ans : The instrument transformers differ from the power transformers mainly by their volt-ampere rating. The instrument transformers have a very low rating of only a few tens of VA e.g 10VA, 50VA, 100VA etc. whereas the power transformers have high KVA rating e.g 25KVA, 200KVA, 500KVA, 1000KVA even up to 1000MVA.