Treadmill blowing main breaker

Thread Starter

PDM31

Joined Jun 29, 2020
7
Had my treadmill for 4 years from new. When using it a few weeks ago it went off. I reached down and the power cord felt loose so i pushed it in. The machine came on then blew the main breaker straight away. Treadmill is located in garage.

Anyway I've narrowed down the issue and it seems to be either the top console or the motor. I've had the motor control board tested by a treadmill engineer and he said it's fine. When i connect the console to the control board the treadmill powers on fine, without the motor connected.

When i disconnect the console and attach the motor to the board, it switches on fine and doesn't blow the breaker. I've also tested the motor using a drill battery and it started moving the belt fine.

However when the console and motor are both attached to the board the breaker blows.

The motor is under guarantee. Any help would be appreciated, is it the console or the motor?
 

Thread Starter

PDM31

Joined Jun 29, 2020
7
Or do you mean into the electricity socket i'm using for the treadmill?

I've tried plugging in a kettle and that worked fine.
 

MaxHeadRoom

Joined Jul 18, 2013
22,894
No, disconnect the motor and attache a 100w lamp to these two wires, it sounds as though the motor is being switched on full voltage instead of ramping up.
But with no command sent from the console, there should be no voltage on the motor wires.
Do you have a meter?
What is the number on the main motor board?
Max.
 

Thread Starter

PDM31

Joined Jun 29, 2020
7
Yes i think you're right Max.

How do i attach a lamp to those two wires though?

I can get a meter from my brother tomorrow. And i will take a picture of the main board and send it.
 

MaxHeadRoom

Joined Jul 18, 2013
22,894
I usually have a couple of lamp holders with pig-tails for testing etc, otherwise you you would need to find a way to hook them up to the motor wiring.
Max.
 

Thread Starter

PDM31

Joined Jun 29, 2020
7
What about if I attach the meter to the red and black connections on the board where the motor attaches and see what the reading is? Would that work or does there need to be an actual load connected.
 

Thread Starter

PDM31

Joined Jun 29, 2020
7
Ok so my Brother (who's a trainee Electrician) came around and brought a meter.

When we put the meter on the motor pins on the control unit and turn the treadmill on there's a reading of between 50v-120v on his meter. The meter doesn't have a specific reading just within a range.

That reading remains the same whether we've got the console unit attached to the Control board or not.

He seems to think because the RCB breaker is the one blowing that there is an earth fault in the motor. I'm curious though as to why there is 50v-120v going to the motor when the start button hasn't been pressed for it to move?

Also when i leave the motor unplugged and try on the console try to lift up the lncline the digital setting shows it going up but nothing is happening and as soon as let go of the button it goes back to zero. The incline has it's own motor doesn't it? Shouldn't that still work? We tested the pins on the control unit for that motor and it was showing as 24v.

Same with the speed, I'm obviously not expecting it to move but I thought by pressing the speed up it would show as going that speed on the console but it just goes straight to back to 0.00mph.
 

MaxHeadRoom

Joined Jul 18, 2013
22,894
It would have been preferable to place a small load on the motor leads, when reading with a high impedance meter, it can record stray currents etc.
Maybe there is carbon dust from the brushes causing a earth ground leakage?
You could lift the ground conductor temporarily so the RCD does not see any possible leakage.
Normally you should not be getting any voltage on the motor leads before a command is entered.
Max.
 

Thread Starter

PDM31

Joined Jun 29, 2020
7
Yes we did lift the ground conductor away from the bottom of the frame and tried it again but it still blew the breaker.

We we're wondering if the issue is that the wires are touching inside but with the motor still being under warranty we didn't fancy taking it apart.
 

MaxHeadRoom

Joined Jul 18, 2013
22,894
You can also spin the motor and see if it generates OK.
Also shorting the leads while spinning should cause a braking effect.
Resistance of leads to frame is also a test, (should show open).
Max.
 
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