Frictional , rotating losses are not common to Transformers and rotating machines. these are specific to rotating machines.
The transformer you describe is being used as a step-down transformer, and is classified as an electrical machine. The transformer could either be a mutual transformer, consisting of two, electrically-isolated coils, or an auto-transformer which uses a common coil between its primary and secondary circuits.
It depends on the design of the transformer but 1 MVA is a common size for an 11 kV / 415 v three-phase transformer.
Neither of these terms is normally applied to a transformer. You may be thinking of a 'mutual tranformer' and an 'autotransformer'. If so, then a 'mutual transformer' is a transformer which has electrically-isolated primary and secondary windings, whereas an 'autotranformer' (the term, 'auto', is misleading and has nothing to do with the transformer being 'automatic'!) has a common and series winding, meaning that the primary and secondary sides are electrically connected to each other.
They all have a rotating commutator in the centre and a coil surrounding it.
It's common to put arcing horns on the HV side of a power transformer to short out voltage spikes arriving from lightning strikes along the line.
These terms appear in the calculation of fault currents. Common sources of fault currents are rotating machines, i.e., motors and generators.
A commutator is an electrical switch that periodically reverses the current direction in an electric motor or electrical generator. A commutator is a common feature of direct current rotating machines.
The transformer you describe is being used as a step-down transformer, and is classified as an electrical machine. The transformer could either be a mutual transformer, consisting of two, electrically-isolated coils, or an auto-transformer which uses a common coil between its primary and secondary circuits.
An auto transformer has one winding with the output being tapped at some point and therefore has no isolation between primary and secondary. This may make it unsafe or illegal in some applications. A common power transformer has separate windings.
a step down transformer is used to lower the voltage from the powerlines into your home. a common slang term for this type of transformer is a pole pig.
It depends on the design of the transformer but 1 MVA is a common size for an 11 kV / 415 v three-phase transformer.
Group III machines
Transformer utilization factor is the ration of power delivered to the load and ac rating of the transformer secondary.
If question is about a transformer's tapped coil then the taps are a way of getting different voltages from one transformer. The end of the transformer's coil is the common point and the taps to this common point will give different voltages depending on where in the coil the taps are taken from.
The most common tattoo machines in use are electromagnetic
Group III machines
An autotransformer is a transformer with at least two windings where a part of one winding (the common winding) is shared between both primary and secondary outputs.