Motor starting case studies

[maladili]

A motor starting case study for any given electrical network can be performed by reduced the network to a smaller equivalent network consisting of a source (generator / grid), the starting motor (largest motor), other large running motor and a lumped load.

This MS Excel based spread sheet is based on this concept and present a small model of electrical network that can be adapted for such motor starting case studies.

This is very helpful especially for quick checks as follows:

1. What is the largest motor size that can be started with a given generator rating
2. What should be the rating of the generator (or nos of generator operated in parallel) for a given load and largest motor size
3. Knowing voltage drop during starting conditions for given motor details and hence deciding the key parameter during design (say max allowable starting current)
4. Deciding the cable size / number of runs etc.

The spread sheet can be downloaded from HERE performs an iterative calculation based on pre-start load inputs and starting motor data. Detailed analysis may be performed with the help of available softwares.

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