Wow this is a great site, wish I had found it sooner.
As a fun project I took apart my older treadmill hoping to figure out a way to make it quieter at low speeds as it hums fairly loudly under load. It has a DC motor which is supplied by a choke which runs off a PC board power supply, not sure what kind of supply it is exactly. I don't see a rectifier or any filter capacitors on the board, just a wire directly to the motor from the board and then one from the board to the choke, then to the motor.
I did check the brushes and cleaned up the commutator but that didn't make any difference. Researching this, it seems like the hum might be from the power to the motor not being pure DC. I am wondering if there is something I could do, like adding a rectifier or filter capacitor to the output of the supply to clean it up and make the motor quieter. The voltage supplied to the motor appears to peak at around 37, under load. I was not able to check the current.
Thanks for any input!
As a fun project I took apart my older treadmill hoping to figure out a way to make it quieter at low speeds as it hums fairly loudly under load. It has a DC motor which is supplied by a choke which runs off a PC board power supply, not sure what kind of supply it is exactly. I don't see a rectifier or any filter capacitors on the board, just a wire directly to the motor from the board and then one from the board to the choke, then to the motor.
I did check the brushes and cleaned up the commutator but that didn't make any difference. Researching this, it seems like the hum might be from the power to the motor not being pure DC. I am wondering if there is something I could do, like adding a rectifier or filter capacitor to the output of the supply to clean it up and make the motor quieter. The voltage supplied to the motor appears to peak at around 37, under load. I was not able to check the current.
Thanks for any input!