Generator Size

FLA of name plates plus 50% and do not start them at the same time

Rule of thumb is 1 KVA per horsepower. For both motors you need at least an 84 KVA generator.

biggest motor, add the other FLA, then add 1/3 of that total.

therefore: 65 a x 2 = 130 a + 41 = 171 + 1/3 = 228 a

I ordered in a 175 KW generator to handle the job.

Dave :)

Bigger/more than you need is often better, but in this case you might be shooting yourself in the foot.

Rather than relying on "general or rules of thumb" to select your generator I would recommend you consult your generator supplier, and discuss your specific requirements. A competent purveyor of generators (especially of this size) will ask the necessary questions to ensure your needs will be met.

Some of the items that should be considered in determining the size need (in addition to the usual) are; will the motors be required to start simultaneously or can they be staged, type of fuel to be used - a liquid gas model converted to Natural/bottled gas will require derating, Diesel Generators need to be run at least 50% or greater load or they will likely develop a wet stack condition (do a goggle search) which could result in severe damage to the prime mover.

Relying on the "general" equations given you without knowledge of your specifics could be problematic, and result in a rather steep/painful learning curve. With the price you are going to pay I suspect a bit of discovery before the purchase is in order.

Louis--