Treadmill sometimes breaks circuit and gives shock

[playman]

I have a treadmill at my gym where I work.
Some times it can be used, but most of the time it breaks the circuit in the Circuit Breaker Box, so you have to go and switch it on again.

some have said that they have had shock from it, I havent tested it but
I belive it is alittle more then normal static charge.

So I belive that there is some leakage some where in it.

what would be the best thing to do, to narrow it down to the problem source.

Please bear in mind i'm a begginer and I've had no school or lessons in electronic repairing,
But I've been doing some hacking and self learning, so my knowledge is limited

[smason]

Re: Treadmill sometimes breaks circuit and gives shock

The first thing I'd check is where the power cable goes in to the unit. Could be frayed, or a loose wire that occasionally shorts to ground blowing the breaker, and possibly zapping people.

[kaboom]

Re: Treadmill sometimes breaks circuit and gives shock

There's probably a triac to control the motor speed. If it 'half shorts,' it'll put DC into the induction motor. There are some newer 'mills that use a DC motor fed from a big switcher, controlled by the front panel.

Is this tripping on ground fault or overcurrent? If it's going out on GF, look at the EMI filter and if DC or brushes in motor, check for carbon brush dust around brush holders creating a leakage path to GND.

If OC trip, check for frayed wires, esp where the line cord goes into the unit. A half-shorted triac on an induction motor will also trip the ckt on OC.

-Paul