Older NordicTrack EXP1000i (NTTL09900) - hot motor and speed control issue
1. Treadmill is old but low mileage. Burning smell - opened cover and motor was hot to touch.
2. Researched online - found TMD. Walking belt and deck have never been lubricated. I did not have the means to measure amperage at this point. Ordered silicone. Cleaned and lubricated belt/deck.
3. I also purchased a DC shunt resistor (50A=50mV) to try to measure motor amps. Unfortunately, my old analog multimeter lowest scale is 0-125mV so I could not discern measurements in the 0-10mV range. But it did seem to be high. I will borrow a better meter.
4. In testing the treadmill in the interim, I have noticed that at no load the speed stays consistent. When walking on it, the speed increases by .5 to 1 mph. Strange. I didn't find any discussions that addressed that specifically. We can probably live with this.
5. Also I was able to easily stall the motor by stepping on and holding the walk belt. Hoping all my issues were the motor brushes. I inspected and the brushes looked okay. The commutator was a little dirty so I cleaned it up. The torque is definitely better.
6. Now I have a better meter. At 2.5 mph: no load = 4A, load = 10A, full incline w/load = 6.5-7A
So. The brushes/commutator probably weren't my only problem. Do you think a new belt is indicated? It doesn't make sense that a worn belt would cause speed up under load.
Thanks.
2. Researched online - found TMD. Walking belt and deck have never been lubricated. I did not have the means to measure amperage at this point. Ordered silicone. Cleaned and lubricated belt/deck.
3. I also purchased a DC shunt resistor (50A=50mV) to try to measure motor amps. Unfortunately, my old analog multimeter lowest scale is 0-125mV so I could not discern measurements in the 0-10mV range. But it did seem to be high. I will borrow a better meter.
4. In testing the treadmill in the interim, I have noticed that at no load the speed stays consistent. When walking on it, the speed increases by .5 to 1 mph. Strange. I didn't find any discussions that addressed that specifically. We can probably live with this.
5. Also I was able to easily stall the motor by stepping on and holding the walk belt. Hoping all my issues were the motor brushes. I inspected and the brushes looked okay. The commutator was a little dirty so I cleaned it up. The torque is definitely better.
6. Now I have a better meter. At 2.5 mph: no load = 4A, load = 10A, full incline w/load = 6.5-7A
So. The brushes/commutator probably weren't my only problem. Do you think a new belt is indicated? It doesn't make sense that a worn belt would cause speed up under load.
Thanks.
Comments
I did add more silicone and ran the treadmill. The current draw seems about the same. I walked for a little while thinking maybe the silicone would work in and operation might normalize. I did have a brief moment when the speed was correct and the amperage was in the 6-8 range. But mostly it ran 1-1.5 mph over input speed of 2.5 and amperage was over 10.
Then....The speed dropped to 0.9 mph. When I unloaded the belt, speed returned to normal. Reloading the belt resumed typical operation of overspeed and overdraw. This drop to 0.9 continued to happen after a few minutes of walking.
So....It appears that you may be correct about the speed controller. Does it make sense that it can maintain consistent speed unloaded but not loaded? Incidentally, the QC label on the large white brick-shaped component on the board appears to have gotten a little "toasty". (Or maybe it's just the adhesive that browned with age?)
Therefore, I should purchase a control board and a belt? (Presuming this machine is worth the investment?)
Regards,
-Scott
Thanks for your help.
I installed the new walking belt and speed controller. The treadmill speed control appears to operate correctly.
However the current draw seems high: at 2.5 mph, unloaded = 5 A, loaded = 11 A.
My initial measurements after belt installation were more in the desired range, but increased to the above numbers as I tensioned the belt until it stopped slipping. (This also drew the belt up against the bottom of the deck sufficiently to keep it from riding on the ends of the belt guides.) Do you have any further recommendations?
The disassembly for the walking belt installation was a challenge with the one piece rear end cap and the retaining clips holding the rear roller shaft to it. The front roller had to come out first. The exploded parts diagram in my manual helped me to figure it all out.
Thank you.
-Scott
Additional lubricating did not seem to make a difference in the amperage draw.
I un-tensioned the drive belt a turn to see if I hadn't over tightened it trying to get rid of slippage. No difference in amps but more slippage.
I loosened the drive belt tension bolt to see if I hadn't over-tensioned the belt. With just the weight of the motor to tension the belt, a cyclic "jumping" of the motor was noticeable. Upon inspection, I could see that the grooving on the belt was deformed. So I will need to order a new one. Not sure if that could cause that much additional load on the motor?
I'd like to pick this thread back up from last spring. I moved the treadmill indoors from the garage in January for my wife. She didn't really try use it much since last spring.
The motor current draw at 2.5 mph is still high: 5A unloaded, 11A unloaded.
And the motor high temp limit opened when she used it for 20+ minutes at 3 mph.
Work done: new speed controller, new walking belt, new drive belt, lubrication, clean motor brushes/commutator/housing.
The walking belt is not hard to push around with my hand. I tensioned the walk belt just enough to prevent slipping and riding up on the edges of belt guide on the bottom of the deck. I don't hear any roller bearing noise and the belt is tracking fine.
There does seem to be some sort of imbalance in the walking belt system: When I turn the motor pulley by hand I can feel a difference in force required - feels kind of like turning a two pole permanent magnet electric motor. I removed the motor belt to feel that the motor spins smoothly. And again the walking belt moves easily by hand and I can't feel a difference in the force required. Not sure that this slight force difference can make the overall motor draw high?
Do you have suggestions for next steps? Perhaps remove the walking belt and inspect the rollers independently for smooth operation?
I have invested a considerable amount in this machine and would like to get it operational.
Thanks.
-Scott
Knoxville