Fuse hot all times

Somewhere, probably in the ignition switch circuit there is a short circuit - otherwise the fuse would not blow. You'll need to take a test meter to each circuit in turn to isolate the circuit and then find the short. Be logical and patient!

The John Deere F525, a front cutting machine, has 3 fuses.
20 Amp
15 Amp
10 Amp

Check the 15 amp fuse. I believe this supports the PTO clutch. If you replace the fuse and it blows again, check the electric clutch. You will likely find burnt or melted wires. The bearings do go out on these clutches causing them to run hot and eventually burn up.

PTO Clutch will not engage: There is a very fine one page discussion on evaluating electric clutches at this site:

http://www.messicks.com/Articles/FixingElectricClutch.aspx

My JD tech manual, which covers the entire LA 100 series, agrees with the electrical specifications. It states that the Electric PTO Clutch should show the following:

Resistance 3.7 ohms
Current Draw 3.25 amps
It does not give the air gap.

It does include a note to check the PTO Clutch Key for damage or if missing. So there is a drive key between the PTO Clutch and the shaft. Additionally, it recommends checking the tightness of the cap screw. That's the screw or bolt that holds the clutch on the shaft.
Cap Screw torque 55 lb-ft (75 N.m).

If the fuse blows, I recommend you check the resistance of the clutch. If the clutch is shorting to ground it will show zero resistance when you ohms the connector wire to a ground position. In which case, you will have to replace the clutch.

Fixing Electric Clutches

Other possibilities.
On the F525 there is a cut-off switch in the hydraulic system. It is a low pressure cut off. If you were running the mower and deck and then it suddenly stopped, it may be low pressure in the hydraulics. It will not automatically reset as you are using the same volume for the drive pumps. Once the oil gets low enough it cuts out the deck drive 1st, then the drive pumps.

There is a distinct possibility that this tractor was originally equipped with a 6 volt system. If it has been upgraded to a 12 volt starter, the ignition will need to have a resistor installed to bring it back to 6 volts.
I could be all wrong on this but it's worth checking.

have some one activate it while you feel it if you feel a click or movement its working if not its bad then get a volt meter set to 12 volts ceck the voltage going to it 1 ground 1 hot if its grounded to frame it may have only 1 hot wire when its activated

It has to have a short either at the starter or the ign. switch just check the wires that carry power and make sure none are earthing out.

Probably the pto switch. Find the 2 wire 'T' plug from the PTO clutch and disconnect. With a voltmeter across the the 2 spades on the tractor side of the plug you should get 12 volts DC with the PTO switch on ( you may need to sit in the seat ). If you get 12 volts at the plug its probably the PTO clutch. If no power then its a fuse or the PTO switch

unplug the clutch and see try it if the fuse doesn't blow then look at the wires going to the clutch make sure they didn't rub on something

look where the wires go threw the frame to the clutch and unplug the connector and try a new fuse if it still blows remove the clutch and inspect the wires they do rub on metal and short of the power

one of the safety switches could be shorted out internally

GO ON LINE TO JOHN DEERE PARTS YOU CAN DOWN LOAD PARTS DIAGRAMS AND WIRING DIAGRAMS ALSO. CHECK THE PLUGS AN THE WIRING HARNESS AND MAKE SURE THEY ARE CLEAN. WITH A VOLT METER YOU CAN CHECK AND SEE WHAT VOLTAGE YOU ARE GETTING TO THAT RELAY. I DON'T HAVE A DIAGRAM TO LOOK AT BUT IF I CAN FIND ONE ONLINE I'LL LET YOU KNOW. HAVE YOU CHECKED FOR A SECOND RELAY