You use a 3 phase rotary converter with a 5hp idler motor to run your 3 phase 5 hp table saw your idler motor get very hot is this normal?

If you are running an equalsized motor as the converter,it's doing a lot of workas a transformer. How is it cooled? Is it open drip proof,does it have a fan,or is it closed. what is the power factorand the grade of insulation? (F, H.) If you can hold your hand on it for several seconds without a burn,that should be about 145 degrees F. That's ok. Above 180 you should cool it. Try a fan, make some air openings and pump air thru it. I used a twin 575HP DCmotor in a Dyno setup by the hour,absorbingup to1500 HP,but we had 3 - 15HP squirrelcage blowers to cool it andthe air came out quite warm. Step 2: use another idler 3phase motor to reduce the load, and put some capacitors on the lines to balance the voltages.

Your application is severe, a table saw can load the motor pretty good, and you can't really expect the full 5 HP under these conditions. Changing to a 7.5 HP idler motor will stiffen up the supply to your saw quite a bit and will run cooler too.