Treadmill amperage spikes? 1

[43st]

We're having an issue with a small treadmill. We're using a 15amp DC motor and when someone is running on the treadmill we're getting current spikes that are faulting the system.

The treadmill is 4' wide, by maybe 5' long on the top, with 6" dia. rollers with a belt linkage to the motor gearbox.

What are your opinions on this? How do consumer treadmills deal with this? My inclination is that a mechanical absorber needs to be implemented on the belt stage to the rollers. Perhaps a flexible spider or helical beam style coupling?

 

[ScottyUK]

A couple of thoughts from the electrical world:

DC machines and drives are expensive compared to AC induction machines and drives. This is partly because DC machines are more complex, and partly because they are becoming a minority interest item with resultant higher costs per unit.

If you use an induction motor and an AC drive then you will have cheaper and more robust basic components. An AC drive running in V/Hz mode will allow the motor to slip a little as the load increases - indeed this is inherent in how an induction motor works - and that might give you some of the 'sponginess' which seems desirable in this application. By contrast with the simple V/Hz drive, a vector drive will almost match a servo drive in capability and produce a very stiff response. In either case, by using a slightly more sophisticated drive you have the option of regenerating into the supply so the exercise machine produces electricity.

If this thread goes too far in to electrickery for the mechanical area you might want to move over to forum237.



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If we learn from our mistakes I'm getting a great education!

 

[43st]

Small update... The clutch is installed and the motor is happy. No noticeable effect on the performer as well.

Thanks for all the helpful comments and ideas.