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[bkenobi]

This is a bit of an odd one that might be better asked on another forum.  That said, you guys have really good ideas so I'll ask anyway and if you know of a better place to ask, I'll try there next.

Background (can skip):
In the NW USA it's dark in the morning and afternoon during the winter so I don't see my yard for a couple months outside of weekends.  I have dogs that need exercise that I can't logistically give them during these months by taking them for a run.  I was given a dog treadmill to help with conditioning.  It works great overall, but there are a couple things I was hoping to do to make it better.  I could buy one that does this type of thing, but these things are quite expensive so I'm inclined to either use this one as is or try to make a couple simple changes if possible.

Issues:
The design is straight out of the 1940's and is very robust.  The dog runs on a long belt (like any other human counterpart) and has a fence on one side and a bar above to attach a lead to.  It has two rollers on the ends and a single motor that drives one roller.  The speed is controlled by adjusting the belt with a hand crank.  The unit has an on/off switch and a 15 minute mechanical timer.  To use the treadmill, the timer must be set to 3+ minutes and the switch turned on.  When the timer runs out or the switch is turned off, the unit stops.

I have 2 issues that I was hoping to address if possible.

• Turn on with a speed ramp - Currently when the treadmill is turned on it immediately jolts to the running speed.  The minimum speed is a walk, but it's pretty jarring.  I was thinking that I could change the switch from an on/off to something with a dimmer so when I flip the switch it takes a bit longer to get moving.  I recall from my bathroom exhaust fan project that there are more than one type of motor and some cannot be controlled this way.  I tried to get a picture of the tag on the motor, but it wasn't cooperating this morning.  What should I look for to know if this is possible?
• Safety cuttoff - It would be nice if there was a way to add a safety cuttoff like what human treadmills have.  I never leave the dog unattended.  I do sometimes attach a lead to the overhead bar to help keep him in place.  If there were an issue, I could either jump up and pick him up or reach down to turn off the treadmill.  However, if the dog is running at a decent pace and went down somehow, he could potentially get a burn on the belt.  I was envisioning adding one of those orange plastic things or possibly some other method to kill things instantly.  This is potentially easy or complicated and, since I'm right next to the dog at all times is not as critical.

[HA Dave]

Some sort of rheostat on the motor? Maybe... that's above my skill level though.

Human treadmills have a dead-man switch. Just imagine a switch that is opened by removing a pin of sorts... breaking the connection. I'd guess you could make a suitable switch out of an old large-sized stereo headphone switch (or even a standard AC lamp plug).

With the prong (male) plug part internally shorted and isolated. Then being attached to the dogs lead. The current would pass from the female part through the male part... and back to the other-side of the female part and on to the treadmill.

If the dog fell... the plug would be pulled... the circuit broken and the motor would stop. And the dog would be free.

Another idea. I have enough lighting in my backyard.... to play a friendly game of baseball. I rarely need it. But once installed (15 years ago) it cost nothing to sit there in case I want it. With modern LED lighting... even using lighting on a large scale is pretty cheap. Maybe... you should light up that area.

[Brian H]

If you could somehow get some information from the motor it would help.

Correct my thoughts if I am incorrect.
The photos seem to show the speed control is a mechanical one. With the fixed speed motor running a intermediate stepped pulley with a belt and the second belt driving the ramp speed can be selected by which step on the intermediate pulley it is using. Changing the step down ratio.

If it is an AC motor it may not be easily changed in speed.
On the off chance it was a DC motor with a motor controller. It may have an acceleration pot and deceleration pot.

 

[bkenobi]

The motor is under the belt on a platform.  I can get to it with a camera if I lift it up, but it's so heavy I will have to get help as well as some jacks to keep from getting crushed.  I'll get the motor specs next chance I have that help.  The tag is partially visible from the easy end to access but it just shows the lower portion with the safety stuff.

That said, I assume it is an AC motor as everything is simply wire nutted together in the control area.  The motor controls appear to be a light switch and a fan timer in series connected directly to the incoming AC.  The speed control is that crank on the side.  Turn CCW and it pivots left and slows the belt.  Turn CW and it pivots to the right and speeds up.  The minimum speed is still a pretty good clip and too much for introducing a puppy especially with the large kick when it starts.

FWIW, I'm glad this was a hand-me-down as these things cost $$$$ new.  This is an older model, but they still don't give them away when you can find them.  I tried a human treadmill with my older dog and he decided it wasn't his thing.  He dug in and stopped the belt.  Smart dog!   

[Brian H]

Don't hurt yourself. Trying to get the motor information.

As your description points to a a single speed AC motor.
With a master Power On Off switch and a timer switch to control the motor.
 
Some I have seen like to surge to full speed in a very short time. Especially if they are a capacitor start or have a start winding in them. Right now I don't have any ideas on slowing down the start up speed surge.

[dave w]

I agree with Brian. I think it is just a AC squirrel cage motor. You would need to find out if it is a capacitor start. If it is NOT a capacitor start, you might be able to use a PWM speed control. But these ain't cheap either.

Although it is very Rube Goldberg you could wire some high wattage INCANDESCENT light bulbs in series with the motor with a shorting switch across each lightbulb socket. I would try a couple 100 watt bulbs to start. Guessing perhaps a 1/2 horse motor, both bulbs should drop it to around half speed IF it can start the belt running (the bulbs will really knock down starting current.) Then close the switches one by one and the motor will speed up as each bulb is shorted across. with out knowing the wattage draw of the motor (a 1 horse AC motor will draw around 750 watts) you may have to compensate with more or less bulbs

[bkenobi]

What type of motor would a router or table saw use?  Harbor freight has a speed controller that seems like an obvious option, but I don't know what I should be checking for to see if it's OK to try.

http://m.harborfreight.com/router-speed-control-43060.html

[HA Dave]

Wait.... we've all seen this before. https://youtu.be/5DxDEoDojJ4

[bkenobi]

Except for the slight drop off difference, it does look pretty close!

This is the motor:
https://www.grainger.com/product/DAYTON-1-HP-Belt-Drive-Motor-6K321

The one on the treadmill is actually 6K321L, but I'm pretty sure it's the same motor.

[Brian H]

What type of motor would a router or table saw use?  Harbor freight has a speed controller that seems like an obvious option, but I don't know what I should be checking for to see if it's OK to try.

http://m.harborfreight.com/router-speed-control-43060.html

That speed control is for a universal AC/DC motor with brushes.
It will not work with your 1Hp AC Capacitor Start Motor.

The L on the end of the motor part number may indicate a different shaft length or maybe mounting arrangement.
 

[bkenobi]

The L on the end of the motor part number may indicate a different shaft length or maybe mounting arrangement.

That's what I figured.  I was assuming it was either the type of shaft (spline etc), length, mounting style, etc.  If I really wanted to get into it, I guess I could swap the motor for another 1HP drive (maybe from a CL human treadmill).  I think I'll just use it as is for now though.  Since I set next to the machine when it's running, the safety issue is not significant.  The slowest speed isn't really that fast, it's just a bit noisy and jerky on startup.  Maybe I'm just trying to find a problem to solve.   

[HA Dave]

I know it can be done... I saw it on YouTube.

[bkenobi]

I swapped out the timer for a 60 minute variant HD sells under the "Defiant" name.  When I opened it, I found that it's actually a GE OEM product and is virtually identical to the one in the treadmill.  I guess HD and Lowes sell GE and Cooper products under cheap name brands for some reason though they are the same as the better quality names.  Peculiar...

One other question that may not be answerable here.  On the 2nd and 3rd pictures there is a dial to adjust the speed of the belt.  Right above that is an indicator for where it's currently set.  This actually has dual purpose as it also is a lubrication port.  If the cap on the top of the indicator is flipped up, there is a very small reservoir that leads down the shaft can be seen.  I know this isn't intended to use axle grease applied via a grease gun, but I'm not sure what it's lubricating nor what type of oil would be used.  I felt it last night after running for 30 minutes and the indicator/lubricator is warm to the touch.  If you look on the 3rd picture, there is a pulley in the center of the two belts.  This pulley floats so it can't be what is being lubricated I don't think.  There appears to be another pulley mostly hidden in this picture (towards the top) but I don't see what it does nor how that would benefit from lubrication.  Anyone have any thoughts?  It's a mystery!

[HA Dave]

........ there is a pulley in the center of the two belts.  This pulley floats so it can't be what is being lubricated I don't think.  There appears to be another pulley mostly hidden in this picture (towards the top) but I don't see what it does nor how that would benefit from lubrication.  Anyone have any thoughts?  It's a mystery!

If this is a speed control... is the floating pulley used to move the belt to the "mostly hidden" pulley... to change the gear ratio/speed?

Everything that spins requires a little lube. A drop or two of household oil or 3-in-one oil should work.

[bkenobi]

It doesn't change pulleys, it pivots and somehow that changes the "gearing".  It was making a little more noise last night, so I suspect whatever keeps the pulley in position on the shafts (clip/snap ring/collar) may have shifted. When I lube it, I'll check on that too.