I’ve just had the following email correspondence below with a guy in the USA – this may be useful if you are also having treadmill motor issues.
Please get in touch if you’ve had similar experiences!
ENQUIRY: Treadmill question
I just found your article about treadmill motor. I have an older Nordic Track treadmill model EXP1000 XL (I am in the USA) and everything worked EXCEPT that it keeps tripping the circuit breaker when in use, usually within 1 minute of startup. It would run continuously at any speed when no load is on the belt. Suspecting that I have a "weak" circuit breaker, I temporarily replace it with a15A automotive fuse, and it acted just as before. The fuse opened up within a minute of running under load. How do I determine that it is the motor that is bad, perhaps a few shorted winding? If it is the motor drawing excessive current, can it be repaired?
Thanks for your email. I find the best way to test a motor is on the machine using an industrial DC motor drive. In this scenario, you are able to test the motor using a known-good drive and you can stand on the running belt and load the motor as in real-life. You will quickly be able to isolate the problem if the fuse blows again in the known-good drive or if the motor arcs and burns excessively whilst accelerating. I appreciate that you will probably not have access to an industrial DC motor drive unit but your local motor rewind specialist may have such a device you can borrow. You don’t get the same loading effect by bench testing a motor or by using a DC battery so my advice is not to bother with these test methods (which seem popular on the internet!).
From what you have told me already and based on my knowledge of the EXP1000 on Europe, I think it is the motor. The only other possibility is the choke which looks like a transformer and is usually screwed to the machine frame near the motor. These often get hot in use and the red insulation on the windings discolours to dark brown if too much current is being drawn which is another symptom of a failing motor. The heating of the choke can cause its insulation to break down which could also pop the fuse. I think the MCB is ok as the machine seems to run fine off-load.
With regard to repairing your motor, my advice is to replace with new. Over here, the price to rewind a motor is about the same as to buy new. The major disadvantage with rewinding a treadmill DC motor is that they have permanent magnets inside which will not normally be replaced as part of a rewind. I have spent good money before on rewinding such motors only to discover that they quickly fail again because the magnets have de-magnetised!
Hope this helps!
REPLY: Dear Treadmill Engineer,
An update: just to test the system, I went ahead and replace the resettable circuit breaker with a 15A fuse (same rating as the CB), and it pops. I then tried a 20 Amp fuse, and the system ran fine under load. I tried all the speeds available while loading it, and the fuse stayed intact. So I did a little research and got curious because in my search I found out that the 2.5HP motor is rated at 18A (1.5HP continuous at 95VDC). So it seemed that the protection circuit is at best marginally designed, thus as the system aged and the motor sees more loading due to age, friction and wear, the CB is probably just nearing its trip point. What do you think?
Yes, I agree. I think Icon do tend to design their products without any safety margins.
Let me know how it goes!