Transformer, Motor, Busbar Overload Standart

Yes, usually the manufacturers go to great extents to make sure their customers know what they have purchased. Generally the standard load is expressed as Full Load Amps (FLA). Different motors have different overload ratings due to start current requirements and possibly other factors.

A transformer overload causes distorted wave shapes and severe heat damage. A busbar overload is generally catastrophic so it could only be for a very short time if at all. But everything has its limits. To give you an understanding about this, consider the following image relating to both overload and underload limits for a computer power supply. Time is a very big factor in the overall consideration.

If you have a transformer rated at 200KVA, then it is overloaded at 200.001KVA. Most people use a standard of 80% of full load as a maximum load just because you have to leave a little room for unexpected events such as start ups of big motors, etc.

A motor, transformer, and busbar are three very different kinds of items. Decisions of how to use them will determine how quickly they fail. The user is generally not the expert on these matters. The manufacturer is responsible for doing the testing on his product. Therefore, the manufacturer is probably going to be the most qualified to answer your question, or they will probably only be in business for a very short time.

Pl. refer to application guides on transformers, motors & protective relays.