Have a 12 lengths mechanical deep well, run by a 3HP US Motor. Wants to change the motor to a 1.5 HP to save on power. Tried this but the motor heats up. I presume I have to change the pulley size and or Flywheel, Right? What's the proper size?

single phase 240VAC. data late will have info. 3 phase usually has 12 leads.

yes it is

Please make sure to trip the breakers for your unit before touching any wires!
horse power (HP)
shaft length and diameter
RPM
Weather or not motor comes with fan and if your fan is removeable from your motor shaft
Voltage
Amperage
Most of this may be on a data plate on the motor itself.
Check this info out from RepairClinic.com
Fan Motor part number 51-21853-11
1/3hp 208-230v 1075 rpm 48 mtr
They didnt come up with your exact unit, but if your motor tag data is the same as this, you should be golden.
Please make sure to trip the breakers for your unit before touching any wires!
https://www.repairclinic.com/PartDetail/Fan-Motor/512185311/2638127

Your thought process is a little backwards. Have you tested the static pressure? If the ducts are too restrictive you DEFINITELY don't need a bigger motor. Obviously the slowest setting is best.

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You want delay fuse instead of fast-acting fuse. Look for delay on product description.
Since the motor has a high amp draw when first starting, then that means surge of heat traveling over wire.
Fuse trips when sensing heat.
Delay fuse will accept high heat for longer period of time before tripping.

You have 1 Hp 6K321 motor from WW Grainger. You can contact grainger.
http://www.grainger.com/Grainger/DAYTON-General-Purpose-Motor-6K321?Pid=search

I recommend that you use 12 gauge wire and 20 amp fuse. Over-sizing wire will save heat loss and prevent damage to motor, and heat damage fuse box.

If you use smaller 14 gauge wire and 15 amp fuse, the motor will heat the wire, especially if length of wire is longer than 100 feet from fuse.
The motor has thermal protection, so motor is not overheating.
The wire is overheating.
http://waterheatertimer.org/Color-codewire.html
http://waterheatertimer.org/See-inside-main-breaker-box.html

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G'day, As a general rule, for each one horsepower of motor size you get on average 4 cubic feet per minute. So 3hp motor = about 12-14 cfm.

Hope this was helpfull.
Regards Andrew Porrelli

Usually the reset for table saw is on the motor itself
Crawl under the table and check it out & check your motor name plate (use a digital camera to photograph the name plate so you can see it large on your computer and have a record of that information)
Look for oil caps at the bearing ends of motor, to see if your motor can be oiled using 3-in-1 oil

If your saw is shutting down, you may not have enough electricity for the motor
Look at motor name plate for volts amps or watts.
Now figure how much electricity your saw need using the formula Volts x Amps = Watts

Next, look at the circuit breaker and size wire
15Amp breaker = 1440+watts
You can figure the breaker load using V X A = W

Next look at your wire going to table saw
14 gauge wire for 15 amp breaker
12 gauge wire for 20 amp breaker
10 gauge wire for 30 amp breaker

You might benefit by running bigger wire to the saw. And adding some oil in the oil caps.
I oiled my table saw and then ran a dedicated 30Amp wire to it, and it runs real good for a 25-year-old craftsman.

yes there are brushes,, but there is also a shaft that goes thru the tube make sure it is not broke or bent,, it happens,, suggest to get a zoeller submersable pump its the best cast iron, float is attached to the unit, will fit in small pits, only 1 plug needed,, cost for pump 100

That information is usually on the data plate on the furnace and on the motor itself. All you need to know now is the HP. Other than that a universal consolidator motor is an easy fix too. It can handle 1/6-1/3HP.