treadmill shuts off???

Can you put a small fan in a spot where it would keep the motor cool?  Sounds like the motor is over-loaded/over-heating.

That or you could slow down to Mach 1 instead of Mach 8. 

Odd. 
Mine shuts off when the timer hits 100.00 min.  Scared the heck out of me the first time it did that. 

What is the model number?  Maybe we can figure this thing out.

good point, i should have added that i tired this too.  i have a "squirrel cage" type blower that i put in front of it and aimed it directly on the motor housing and it may have lengthened the time i could go on it a little.....but it still shut off...

i normally run in it at 7.5-8.0
last night i set it at 7.0 and it didnt even make it 1/4 of a lap     i think it likes to go fast....

How old is that treadmill? Sounds like it is on its last legs.

its a ProForm 745 CS

Sent ya the manual.  They have a helpline on it you could try.
Page 22 is the only thing related to it shutting off during use.

This is a shot in the dark, but could you be accidentally catching your foot between the belt and the side?  That might cause the machine to think the belt was caught and automatically turn off as a safety measure.

The overheating thing seems more likely, though.

I have a proform also perhaps because its is in your garage it is collecting to much dust in the motor coil take the cover off and verify the vent holes are clear ,actually first unplug it , then if you have a air compressor blow air in the vent holes to clear it out , it worked for me , also vaccume any debri arount the motor also , and continue using the fan

Is there any reason to suspect a motor fault? I would start trouble shooting the interlocks that will cause a power trip to the motor. Most treadmils have a magnet-sensor that shuts the machine off if the magnet comes of. The sensor could be going wonky. Treadmill may have a ground-fault circuit interupt - could it be tripping on a short or leakage somewhere? Are there internal fuses?

To start with, I'd get a Fluke meter (or any other meter that measures current draw) and measure how much juice is going in as you're running. Ramp up the machine to a high speed and measure the current draw.  Current (Amps) x Voltage (probalby 120V /1phase service) = power (Watts).  741 Watts = 1 horsepower. What is your treadmill's maximum horsepower rating? Multiply it by 746, then divide it by 120 and you'll see what your max current draw should be.  If your current spikes up to above that then you have a short or motor problem.

hey, you could be on to something.  i do notice quite a large amount of static once i get hammering away. maybe i need to hang some chains off me like the ambulances have? 
i'll try to work on the static stuff....see if there's something to it and let you know!

I've never had a treadmill shut off while I was using it. I have to finish all my tedious and boring treadmill runs. Damn treadmill.

Most likely cause is a worn or non lubricated belt causing excessive work from the motor.

*sigh*

I quess it IS not far from the start of another season, so we might as well get the trash talking started.

Ok, let's go...

Well why don't you just get your behind outside and actually do some real running and leave the treadmill for your dog? A little snow too scary? You should have done the Jingle Bell run, by the way. All the fast people stayed home that day.

Is the motor actually hot when the OL switch kicks out? If it is, then you possibly could have some binding on the motor shaft/gear box that's putting an additional load on the motor.

Just wanted to get my Posts count over 700

you're right.  i didnt race that day!  

online tech support told me that i need a left-handed wind shifter to keep it from overheating. 

I was thinking the same thing. Most of these call for lubricating the deck under the belt on a regular basis. If you don't do this, there is excessive drag on the motor. Some of them specify to lubricate with silicone spray; mine is supposed to be waxed.

If the motor is getting hot, two things could account for this:
1) it's working too hard
2) whatever is supposed to cool the motor isn't

If it's not a deck/belt lubrication thing, I liked the idea above about dust/crud works blocking airflow. If you have an air compressor, it's an easy way to blow the dust out of things.

Sometimes the motors do wear out and need to be replaced.

I would also consider calling the manufacturer. I got some good help from the Vision treadmill people once that way.