Monday, 6 April 2015

Newly replaced treadmill motors smells of burnt. How to solve the issue

Question:
I sold a new motor (8 cm diameter) to one customer. First he told me the motor was too hot and finally it was damaged (burnt). After that he told me he through away the complete treadmill...

Which tests and maintenance can they do on these cases? It seems the treadmill has some kind of resistence which overload the motor, isn´t it? I only can say running belt and drive belt, is any other thing which can overload the motor?



Answer

90% is a running belt problem (too much friction = belt to be replaced).
10% is too much tension on belt (drive or running), damaged (scracthed) deck (running board), damaged rollers (quite uncommon).

Basic tests for treadmills - standard current values



The ideal test is to use a multimeter connected in A-DC and check how much current consumption in different situations.
If the current consumption is high, motor becomes hot, so the problem should be evident.

I'd suggest anyway when there are problems to make sure the customer checks with amperometer how much current to the motor. The reason is that in this way it's quite precise and they can improve and see by themself the improvement.

I usually suggest to measure A-DC (direct current) with no load (for 180V motor this should be below 1,5/1,7A) and with load (for 180V motor this should be below 6/7A), then to remove tension to belt and check again (it must be lower), another test is to walk on the edges (left&right) of the belt. If there is much difference walking on the edges and in the middle, it's because the belt is more damaged in the middle -> so replace belt.

If the A w/o load is high, it worths checking with less tension on drive belt.
If the A reading seems wrong, please double check. The value should be taken on RED or BLACK cables going to motor. As the tension is regulated by PWM high frequency, some multimeters could fail in reading the values.

130V motors usually have a current consumption up to 50% higher than 180V motors.

Why lubricating is not always the final solution?



Let's say the most common problem is the running belt. Until now as a final solution I always found the replacement of the belt (except some cases with evident problems in the mechanics). Some people use lube and the situation becomes little better, but if the belt is old this effect doesn't last much, as the running belt becomes less flexible over time and this has some effect on friction and motor load.

Too smooth rollers causing excessive tension on treadmill running belt






Another mechanical issue is sometimes the roller is too smooth because of long usage. The roller must make friction on the belt, but sometimes it becomes slippery. In this case, the belt has to be tensioned much (otherwise it slips on the roller) and this brings additional load to the motor (and to the rollers bearings). Usually replacing the belts solves the problem because the new belt has better grip on the roller and less friction on the deck (because it's more flexible), while the final solution in case of slippery rollers is lathe machine.

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